JP2006129039A - Transmitter, temperature compensation method of rf signal, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter with a temperature compensation function that is downsized more and smaller in the power consumption than prior arts. <P>SOLUTION: A temperature compensation processing section 40 directly applies digital signal processing to a digital modulation signal being an output of a modulation signal generating circuit 30 in response to a temperature detected by a temperature detector 10 to carry out temperature compensation. Since the processed digital modulation signal passes through a D/A conversion circuit 50 after the temperature compensation processing, the required number of D/A conversion circuits 50 can be decreased by one in comparison with prior arts and downsizing and furthermore energy saving can be attained attended with above. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transmitter that performs temperature compensation of a transmission output level.

  In the transmitter, the transmission output level of the output signal may fluctuate due to various external and internal factors such as the ambient temperature. Therefore, many transmitters capable of compensating the transmission output level have been proposed.

  An example of such a transmitter is shown in FIG. 5 (conventional example 1). In the transmitter of Conventional Example 1, the digital modulation signal generated by the modulation signal generation circuit 140 is D / A converted by the D / A conversion circuit 141 to generate an IF signal. The generated IF signal and the output of the local oscillator 142 are mixed by the mixer 143 and then amplified by an AGC (Automatic Gain Control) amplifier 144 and an amplifier 145. After amplification, the signal is transmitted as RF signal from the antenna 148 via the coupler 146 and the filter 147.

  As described above, the transmission output level of the RF signal may change under the influence of the ambient temperature of the transmitter. In Conventional Example 1, the transmission output level is compensated by feedback control in order to keep the transmission output level constant.

  In the feedback control, first, the output of the amplifier 145 having a level substantially equal to the transmission output level is detected by the diode detection unit 149 via the coupler 146. Next, the detection output is converted into a digital signal by the A / D conversion circuit 150. This digital signal is compared with the transmission output initial value stored in the memory 151 in the comparator 152. Here, the transmission output initial value indicates a desired transmission output level. The transmitter is configured to transmit an RF signal having a transmission output level corresponding to a transmission output initial value at a reference temperature (for example, normal temperature: 25 ° C.). Therefore, the output of the comparator 152 represents the variation of the transmission output level corresponding to the temperature change. The arithmetic / correction processing circuit 153 receives the output of the comparator 152, calculates how many dB should be adjusted, and generates a gain control digital signal representing the calculation result. The gain control digital signal is D / A converted by the D / A conversion circuit 154 and supplied to the AGC amplifier 144 as a gain control signal. The AGC amplifier 144 adjusts the gain by this gain control signal and compensates the temperature of the RF signal.

  Conventional example 1 is an example in which the temperature compensation of the transmission output level is performed by feedback control (closed loop control), but as shown in FIG. 6, the temperature compensation of the transmission output level is performed by feedforward control (open loop control). There is also a transmitter to perform (refer to Conventional Example 2: Patent Document 1). Of the constituent elements of the transmitter of the conventional example 2 shown in FIG. 6, the same constituent elements as those shown in FIG.

  In the transmitter of Conventional Example 2, instead of detecting the output of the amplifier 145 as in the transmitter of Conventional Example 1, the ambient temperature of the transmitter is detected by the temperature detector 155, and the gain corresponding to the detected temperature is obtained. A control signal is generated, and with this, the gain in the AGC amplifier 144 is controlled.

  The temperature detector 155 includes, for example, a thyristor and outputs a voltage signal corresponding to a temperature change. The output of the temperature detector 155 is A / D converted by the A / D conversion circuit 150 and input to the calculation / correction processing circuit 156. When the output of the temperature detector 155 is received via the A / D conversion circuit 150, the arithmetic / correction processing circuit 156 refers to the temperature correction value stored in advance in the memory 157 and performs an AGC amplifier 144 for temperature compensation. A gain control digital signal for controlling the gain of the signal is generated. The gain control digital signal is D / A converted by the D / A conversion circuit 154 and supplied to the AGC amplifier 144 as a gain control signal, as in the case of the first conventional example. The gain of the AGC amplifier 144 is adjusted by the gain control signal, and the transmission output level of the RF signal is temperature compensated.

JP 2000-165261 A

  In the feedback control by the transmitter of Conventional Example 1, detection by the diode detection unit 149 becomes important in correcting the transmission output level. However, it is difficult to detect weak radio waves with diode detection. For example, some radio waves from a radio station that do not require a license have a weak amplitude of 500 uV / m at a distance of 3 m, but it is difficult to detect such radio waves using the diode detection method. In this case, even if the transmission output level is corrected according to the result of the diode detection, the level cannot be compensated.

  In contrast, in the case of the transmitter of Conventional Example 2, the ambient temperature of the transmitter is detected using a temperature detector 155 with high reproducibility such as a thyristor, and the transmission output level is controlled according to the detected temperature. Therefore, the problem that the transmitter of the conventional example 1 has does not occur.

  However, as is apparent from FIG. 6, in the case of the transmitter of Conventional Example 2, two D / A conversion circuits 141 and 154 are necessary. The D / A conversion circuit is one of relatively large hardware components and consumes a large amount of power. However, the D / A conversion circuit 141 used for analog conversion of a digital modulation signal is used in the configuration of the second conventional example. The D / A conversion circuit 154 used for analog conversion of the output of the arithmetic / correction processing circuit 156 must be separated. For this reason, the transmitter of Conventional Example 2 has a limit in miniaturization, and there is a limit in reducing the power consumption of the transmitter.

  The present invention provides a transmitter having a temperature compensation function that relaxes the limitations on miniaturization and lower power consumption of the conventional example 2, and has a smaller size and lower power consumption than the conventional transmitter. This is the issue.

  The transmitter of the present invention that solves the above-mentioned problems is a transmitter in which the transmission output level of the RF signal fluctuates according to a change in ambient temperature, detects the temperature of the own device, and generates a detection signal indicating the detected temperature. The first means for generating, the modulation signal generating means for generating the digital modulation signal converted into the RF signal, the correction amount of the transmission output level corresponding to the temperature are stored, and the temperature indicated by the detection signal is stored. Temperature compensation processing means for performing temperature compensation of the transmission output level of the RF signal based on the digital modulation signal after digital signal processing by digital signal processing of the digital signal based on the corresponding correction amount and the digital modulation signal; Second means for generating the RF signal based on a digital modulation signal subjected to digital signal processing for temperature compensation of the transmission output level.

The digital modulation signal is directly subjected to temperature compensation processing. That is, the processing for temperature compensation conventionally performed by analog processing by the AGC amplifier is performed by digital processing. Therefore, conventionally, two D / A conversion circuits for the digital modulation signal and the control signal for the AGC amplifier are required for the digital modulation signal after temperature compensation. As a result, the transmitter itself can be reduced in size and power consumption.
Since such a transmitter does not perform feedback control and performs temperature compensation by feedforward control, it is useful as a transmitter that handles weak radio waves of a wireless station that does not require a license, for example.

  In such a transmitter, the temperature compensation processing means can generate a digital signal with the following configuration, for example. For example, the temperature compensation processing means stores the correction amount in association with the corresponding temperature and stores the transmission output temperature correction storage means, and the correction amount corresponding to the temperature represented by the detection signal from the transmission output temperature correction storage means. A correction value selection means to select; an initial value holding means for holding a value of a transmission output level at a predetermined reference temperature; a correction amount selected by the correction value selection means; and the value held by the initial value holding means And means for generating the digital signal. In such a configuration, referring to the transmission output temperature correction storage means, the correction amount can be readily known, so that a digital signal can be easily generated.

  Further, the temperature compensation processing means, a temperature determination value storage means for storing a plurality of temperature ranges in association with representative values representing each temperature range, and a temperature represented by the detection signal generated by the first means, It is determined which temperature range of the temperature determination value storage means belongs, temperature specifying means for specifying a representative value of the temperature range, and the correction amount corresponding to each representative value is associated with the representative value. Transmission output temperature correction storage means for storing the correction value, correction value selection means for selecting a correction amount corresponding to the representative value specified by the temperature specifying means from the transmission output temperature correction storage means, and transmission output at a predetermined reference temperature Initial value holding means for holding a level value; means for generating the digital signal from the correction amount selected by the correction value selection means and the value held by the initial value holding means; It may be configured to include. In this case, since the correction amount is determined by the representative value of temperature, the storage capacity of the transmission output temperature correction storage means can be reduced. Further, the representative value can be easily specified only by referring to the temperature judgment value storage means.

  If the temperature determination value storage means is configured to hold, for example, a threshold temperature that represents the boundary of each temperature range, the temperature specifying means sequentially compares the temperature represented by the detection signal with the threshold temperature to determine the temperature. By configuring so as to determine the temperature range to which it belongs, it is possible to easily know which temperature range the detected temperature belongs to, and it becomes easy to specify the representative value.

  Assuming that each storage means of the temperature compensation processing means as described above is rewritable, even if the transmitter is used in various environments, it is only necessary to rewrite the contents of each storage means. Quantity can be provided. Therefore, it becomes easy to stabilize the transmission output level of the RF signal of the transmitter in any use environment.

  An example of digital signal processing is multiplication processing. In this case, for example, the temperature compensation processing means may be configured to perform temperature compensation of the transmission output level by multiplying the digital signal and the digital modulation signal.

  In the transmitter according to the present invention as described above, the first means can be configured using a diode or a thyristor. When these are used, the temperature detection means can be configured to generate the detection signal based on a forward voltage that changes depending on the temperature dependency of the diode or a voltage that changes depending on the temperature dependency of the thyristor.

  The RF signal temperature compensation method of the present invention detects a temperature of the own device, generates a detection signal representing the detected temperature, a means for generating a digital modulation signal converted into an RF signal, and a temperature The amount of correction of the transmission output level of the RF signal corresponding to is stored, processing means for performing temperature compensation of the transmission output level, and RF output from a predetermined antenna based on the corrected digital modulation signal And means for generating a signal. The processing means selects a correction amount according to the temperature represented by the detection signal, generates a digital signal according to the selected correction amount, and digitally generates the generated digital signal and the digital modulation signal. And performing temperature compensation of the RF signal transmission output level based on the digital modulation signal after the digital signal processing by performing the signal processing.

  The computer program of the present invention detects the temperature of its own device and generates a detection signal representing the detected temperature in a computer having a transmitter in which the transmission output level of the RF signal fluctuates according to a change in ambient temperature. Means for generating a digital modulation signal converted into the RF signal, storing a correction amount of the transmission output level corresponding to the temperature, and a digital signal based on the correction amount corresponding to the temperature represented by the detection signal; Means for performing digital signal processing on the digital modulation signal to perform temperature compensation of the transmission output level of the RF signal based on the digital modulation signal after the digital signal processing, and digital signal processing for temperature compensation of the transmission output level. A computer program for forming means for generating an RF signal based on a digital modulation signal made.

  According to the transmitter of the present invention, the digital modulation signal is directly corrected in accordance with the temperature detected by the temperature detection means to perform temperature compensation, and then D / A conversion is performed by the D / A conversion means. The required number of / A conversion means can be reduced by one. Accordingly, size reduction and further reduction in power consumption are possible.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a transmitter according to the present invention. This transmitter performs temperature correction of the transmission output level of the RF signal according to the temperature of the own device. The transmitter includes a temperature detector 10, an A / D conversion circuit 20, a modulation signal generation circuit 30, a temperature compensation processing unit 40, a D / A conversion circuit 50, an RF signal generation unit 60, and an antenna 70. The modulation signal generation circuit 30 and the temperature compensation processing unit 40 are components for performing digital signal processing, and may be provided as an integral part. Further, the modulation signal generation circuit 30 and the temperature compensation processing unit 40 may be realized by causing a processing device such as a general-purpose CPU or DSP to execute the computer program of the present invention.

  The temperature detector 10 detects a temperature around the transmitter and generates a detection voltage signal representing the temperature. The detected voltage signal is an analog signal that changes according to the detected temperature. The temperature detector 10 includes, for example, a diode, and can detect a change in ambient temperature as a voltage change using the temperature dependence of the forward voltage of the diode. For example, when the forward current is kept constant, the temperature dependence of the Si diode or Ge diode is −2 mV / ° C. Using this, the voltage change that responds linearly to the temperature change can be reproduced with high reproducibility. Obtainable. In addition to the above-described configuration, the temperature detector 10 can also be configured using the temperature dependence of a thyristor as in the related art.

  The A / D conversion circuit 20 A / D converts the detection voltage signal input from the temperature detector 10 to generate a digitized detection voltage signal, that is, a detection digital signal. The generated detection digital signal is input to the temperature compensation processing unit 40.

  The modulation signal generation circuit 30 has the same function as the modulation signal generation circuit 140 of the prior art, and generates a digital modulation signal. Since it is the same as that of the prior art, the description is omitted here. The digital modulation signal is an RF signal output from the transmitter after digital signal processing for temperature compensation is performed.

  The temperature compensation processing unit 40 performs digital signal processing corresponding to the detected digital signal on the digital modulation signal generated by the modulation signal generation circuit 30, and generates a temperature compensated digital modulation signal as a result. is there. The generated temperature-compensated digital modulation signal is input to the D / A conversion circuit 50. The temperature compensation processing unit 40 generates a temperature compensation signal that is a digital signal representing the correction amount of the transmission output level according to the detected digital signal, and performs digital signal processing using the temperature compensation signal and the digital modulation signal. Thus, temperature compensation of the transmission output level when the digital modulation signal is converted into an RF signal and output is performed.

  The D / A conversion circuit 50 performs D / A conversion on the temperature-compensated digital modulation signal input from the temperature compensation processing unit 40, and generates a temperature-compensated IF signal that is an analog signal corresponding to the temperature-compensated digital modulation signal. Is to be generated. The generated temperature compensated IF signal is input to the RF signal generator 60.

  The RF signal generation unit 60 performs predetermined analog processing on the temperature compensated IF signal to generate an RF signal, and transmits the RF signal to the outside of the transmitter via the antenna 70. The RF signal generation unit 60 is provided in a local oscillator 61, a mixer 62 that mixes the output of the local oscillator 61 and the temperature compensated IF signal, an amplifier 63 provided in the subsequent stage of the mixer 62, and a subsequent stage of the amplifier 63. And a filter 64 that sends out an RF signal to the antenna 70. The local oscillator 61, the mixer 62, the amplifier 63, and the filter 64 are the same as the local oscillator 142, the mixer 143, the amplifier 145, and the filter 147 of the related art, respectively, and have the same functions as the conventional one. . Therefore, description is abbreviate | omitted here. Note that an AGC amplifier may be provided between the mixer 62 and the amplifier 63. By providing the AGC amplifier, the gain can be adjusted when the transmission output level is corrected for reasons other than temperature compensation.

  The temperature compensation processing unit 40 will be described in detail. The temperature compensation processing unit 40 includes a temperature determination value table 41, a temperature specifying unit 42, a transmission output temperature correction table 43, a correction value selection circuit 44, an initial value holding unit 45 for holding a transmission output initial value, a first multiplier 46, And a second multiplier 47. The temperature judgment value table 41 and the transmission output temperature correction table 43 are logically separate bodies, but physically may be stored in the same rewritable memory.

  The temperature judgment value table 41 has contents as shown in FIG. 2, for example. This table is a table that stores a plurality of temperature ranges in association with representative values (for example, center values) that represent the respective temperature ranges. In this embodiment, the temperature ranges detectable by the temperature detector 10 are L1 (to t1), L2 (t1 to t2), M1 (t2 to t3), M2 (t3 to t4), M3 (t4 to t5). , H1 (t5 to t6), and H2 (t6 to), the representative values are l1, l2, m1, m2, m3, h1, and h2. Among these, m2 which is a representative value of M2 is a reference temperature. Each temperature range L1 (to t1), L2 (t1 to t2), M1 (t2 to t3), M2 (t3 to t4), M3 (t4 to t5), H1 (t5 to t6), H2 (t6 to) The representative values l1, l2, m1, m2, m3, h1, and h2 take discrete values.

  The temperature determination value table 41 holds a threshold temperature that is a boundary between two adjacent temperature ranges. For example, since the threshold temperature serving as the boundary between the temperature range L1 and the temperature range L2 is t1, the threshold temperature t1 is stored in association with the combination of the temperature range L1 and the temperature range L2. Similarly, the threshold temperature t2 for the combination of the temperature range L2 and the temperature range M1, the threshold temperature t3 for the combination of the temperature range M1 and the temperature range M2, and the combination of the temperature range M2 and the temperature range M3. The threshold temperature t4 is associated with the threshold temperature t5 for the combination of the temperature range M3 and the temperature range H1, and the threshold temperature t6 for the combination of the temperature range H1 and the temperature range H2.

  The temperature specifying unit 42 determines which temperature range of the temperature determination value table 41 the temperature detected by the temperature detector 10 belongs to, and specifies the representative value. When the detection digital signal is input from the A / D conversion circuit 20, the temperature specifying unit 42 detects the temperature indicated by the detection digital signal within the temperature ranges L1, L2, M1, M2, M3, H1, and H2. A representative value of the temperature range is specified by determining which one belongs. The identified representative value (temperature) is input to the correction value selection circuit 44.

  Since the temperature determination value table 41 has the contents as shown in FIG. 2, the temperature specifying unit 42 can easily specify the representative value mainly only by the comparison process. For example, when the detected temperature tx detected by the temperature detector 10 belongs to the temperature range M1, the representative value is specified by the following comparison process. First, the temperature specifying unit 42 compares the detected temperature tx with the threshold temperature t1, and determines that the detected temperature tx is higher. Since the detected temperature tx is higher than the threshold temperature t1, the temperature specifying unit 42 next compares the detected temperature tx with the threshold temperature t2. Since the temperature specifying unit 42 determines that the detected temperature tx is higher than the threshold temperature t2, next, the detected temperature tx is compared with the threshold temperature t3. Since the temperature specifying unit 42 determines that the threshold temperature t3 is higher than the detected temperature tx, it can be seen that the detected temperature tx is between the threshold temperature t2 and the threshold temperature t3. As a result, the temperature specifying unit 42 knows that the detected temperature tx belongs to the temperature range M1.

  The transmission output temperature correction table 43 is a table that stores a representative value of temperature and a correction value corresponding to the representative value in association with each other. The correction value is determined in advance by the temperature difference between the corresponding representative value and the reference temperature (m2), and this determines the final output correction amount. In the case of the reference temperature, the temperature difference is 0 and there is no need for temperature compensation, so the correction value is “0”.

  The correction value selection circuit 44 refers to the transmission output temperature correction table 43 and selects a correction value corresponding to the detected temperature. The correction value selection circuit 44 receives a representative value from the temperature specifying unit 42 and selects a correction value by referring to the transmission output temperature correction table 43 based on this representative value. Yes. The selected correction value is input to the first multiplier 46.

  The initial value holding unit 45 holds a digital signal representing the value of the transmission output level (transmission output initial value) at the reference temperature of the RF signal. The initial value holding unit 45 may be rewritable. In this case, the initial value holding unit 45 can cope with a change in the transmission output level at the reference temperature of the RF signal.

  The first multiplier 46 generates a temperature compensation signal from the correction value selected by the correction value selection circuit 44 and the transmission output initial value held in the initial value holding unit 45. The generated temperature compensation signal is input to the second multiplier 47. The temperature compensation signal is a digital signal for performing temperature compensation on the digital modulation signal, and is a signal for compensating a transmission output level when the digital modulation signal is converted into an RF signal. Here, the first multiplier 46 multiplies the transmission output initial value and the correction value to generate the temperature compensation signal. However, the present invention is not limited to this, and the transmission output initial value and the correction value May be generated by performing some other calculation.

  The second multiplier 47 generates a temperature-compensated digital modulation signal from the digital modulation signal and the temperature compensation signal. When the temperature-compensated digital modulation signal is converted into an RF signal, its transmission output level is compensated for the ambient temperature. Here, the temperature-compensated digital modulation signal is generated by multiplying the digital modulation signal and the temperature compensation signal by the second multiplier 47, but the present invention is not limited to this, and the digital modulation signal and the temperature You may make it produce | generate by performing some other calculation from a compensation signal.

  By performing the following processing by the transmitter as described above, an RF signal that is temperature-compensated for the transmission output level is output. FIG. 4 is a diagram showing the flow of such processing.

  First, before the transmitter outputs an RF signal, the temperature detector 10 detects the temperature around the transmitter (step S10). The temperature detector 10 generates a detected temperature signal representing a voltage corresponding to the detected temperature. The generated detected temperature signal is sent from the temperature detector 10 to the A / D conversion circuit 20. The A / D conversion circuit 20 A / D converts the detection voltage signal sent from the temperature detector 20 to generate a detection digital signal (step S20). The detected digital signal represents the detected temperature as a digital signal. For example, an analog signal having a voltage corresponding to the detected temperature is output from the temperature detector 10, and this analog signal is a detected voltage signal. The A / D conversion circuit 20 A / D converts the detection voltage signal that is an analog signal to generate a detection digital signal that is a digital signal. As a result, the detected temperature is represented by a digital signal.

  The detected digital signal is sent from the A / D conversion circuit 20 to the temperature specifying unit 42 of the temperature compensation processing unit 40. The temperature specifying unit refers to the temperature determination value table 41, confirms in which temperature range the detected temperature represented by the detected digital signal is, and specifies a representative value (step S30). The temperature specifying unit 42 checks the temperature range of the detected temperature represented by the detected digital signal, for example, by the above-described comparison process. When the temperature range of the detected temperature is confirmed as a result of the comparison process, the temperature specifying unit 42 sends a representative value of the temperature range to the correction value selection circuit 44.

  The correction value selection circuit 44 refers to the transmission output temperature correction table 43 and selects a correction value corresponding to the representative value sent from the temperature specifying unit 44 (step S40). In the transmission output temperature correction table 43, correction values are determined corresponding to the representative values. For this purpose, the correction value selection circuit 44 only needs to read the correction value corresponding to the representative value sent from the temperature correction specifying unit 42 from the transmission output temperature correction table 43. The read correction value is sent from the correction value selection circuit 44 to the first multiplier 46.

The first multiplier 46 generates a temperature compensation signal in accordance with the correction value sent from the correction value selection circuit 44. The first multiplier 46 reads out the transmission output initial value stored in the initial value holding unit 45 and multiplies the initial value by the correction value to generate a temperature compensation signal. The temperature compensation signal is sent to the second multiplier 47.
The second multiplier 47 multiplies the digital modulation signal sent from the modulation signal generation circuit 30 and the temperature compensation signal sent from the first multiplier to generate a temperature compensated digital modulation signal (step S50). Thereby, temperature compensation of the transmission output level of the RF signal is performed. The generated temperature-compensated digital modulation signal is sent from the second multiplier to the D / A conversion circuit 50.

The D / A conversion circuit 50 D / A converts the temperature compensated digital modulation signal sent from the second multiplier 47 of the temperature compensation processing unit 40 into a temperature compensated IF signal that is an analog signal (step S60). . The temperature compensated IF signal is sent from the D / A conversion circuit 50 to the RF signal generator 60. The RF signal generation unit 60 generates an RF signal from the temperature compensated IF signal (step S70). The RF signal generation unit 60 first mixes the temperature compensated IF signal sent from the D / A conversion circuit 50 and the output of the local oscillator 61 by the mixer 62. Thereafter, the output of the mixer 62 is amplified by an amplifier 63 and filtered by a filter 64 to generate an RF signal.
The RF signal generated by the RF signal generation unit 60 is output from the antenna 70 (step S80). By such a processing procedure, a temperature-compensated RF signal can be output.

  In the transmitter that performs the intermittent operation, the temperature detection in step S10 to the output of the RF signal in step S60 are repeatedly performed. In a transmitter that performs constant transmission, temperature detection is always performed even during transmission of an RF signal, and a temperature-compensated RF signal is always generated.

In the transmitter of FIG. 1, the detected temperature detected by the temperature detector 10 is represented by a detected voltage signal that is an analog signal, and the detected voltage signal is converted into a digital signal by the A / D conversion circuit 20 and then the temperature compensation processing unit. However, the present invention is not limited to this, and the analog signal may be supplied to the temperature compensation processing unit 40. If the temperature compensation signal input to the second multiplier 47 is supplied as a digital signal, the temperature compensation of the RF signal by the digital modulation signal can be performed by digital processing. For this reason, it is possible to perform processing using an analog signal until immediately before generating the temperature compensation signal.
For example, the temperature specifying unit 42 of the temperature compensation processing unit 40 may receive the detection voltage signal directly from the temperature detector 10 and confirm which temperature range the detection temperature represented by the detection voltage signal belongs to. The temperature specifying unit 24 is configured as an analog-mixed circuit, and the representative value is specified directly from the detected voltage signal. In other words, either the detection voltage signal or the detection digital signal can be used as the detection signal of the present invention.

In the embodiment as described above, temperature compensation is performed directly on the digital modulation signal by digital signal processing. For this reason, it is possible to reduce the number of D / A conversion circuits conventionally required to be two for the digital modulation signal and the gain control digital signal to one. Along with this, it is possible to reduce the size of the transmitter and further save energy.
Since this transmitter performs temperature compensation of the transmission output level by feedforward control (open loop control), it is suitable for a transmitter that transmits weak radio waves.
In addition, since the contents of the temperature judgment value table 41 and the transmission output temperature correction table 34 can be rewritten, the contents can be rewritten according to the environment in which the transmitter is used, so that it can be placed in various environments. Appropriate RF signal transmission power level temperature compensation can be realized.

It is a block diagram which shows schematic structure of the transmitting apparatus of this embodiment. It is an illustration figure of the temperature determination value table of this embodiment. It is an illustration figure of the transmission output temperature correction table of this embodiment. It is a processing flowchart until the RF signal by which the temperature compensation was carried out by the transmitter of this embodiment is output. It is a block diagram which shows the structure of the transmitter by the prior art example 1. FIG. It is a block diagram which shows the structure of the transmitter by the prior art example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Temperature detector 20 A / D conversion circuit 30 Modulation signal generation circuit 40 Temperature compensation process part 41 Temperature judgment value table 42 Temperature specific | specification part 43 Transmission output temperature correction table 44 Correction value selection circuit 45 Initial value holding | maintenance part 46 1st multiplier 47 Second multiplier 50 D / A conversion circuit 60 RF signal generator 61 Local oscillator 62 Mixer 63 Amplifier 64 Filter 70 Antenna

Claims (9)

In the transmitter in which the transmission output level of the RF signal fluctuates according to changes in the ambient temperature,
First means for detecting the temperature of the device and generating a detection signal representing the detected temperature;
Modulation signal generation means for generating a digital modulation signal that is converted into the RF signal;
The transmission output level correction amount corresponding to the temperature is stored, and the digital signal based on the correction amount corresponding to the temperature represented by the detection signal and the digital modulation signal are digital signal processed, so that the digital signal processing Temperature compensation processing means for performing temperature compensation of the transmission output level of the RF signal based on a digital modulation signal;
Second means for generating the RF signal based on a digital modulation signal subjected to digital signal processing for temperature compensation of a transmission output level,
Transmitter. The temperature compensation processing means includes
Transmission output temperature correction storage means for storing the correction amount in association with the corresponding temperature;
Correction value selection means for selecting a correction amount corresponding to the temperature represented by the detection signal from the transmission output temperature correction storage means;
Initial value holding means for holding the value of the transmission output level at a predetermined reference temperature;
Means for generating the digital signal from the correction amount selected by the correction value selection means and the value held by the initial value holding means;
The transmitter according to claim 1. The temperature compensation processing means includes
Temperature determination value storage means for storing a plurality of temperature ranges in association with representative values representing each temperature range;
A temperature specifying means for determining which temperature range of the temperature determination value storage means the temperature represented by the detection signal generated by the first means belongs, and specifying a representative value of the temperature range;
Transmission output temperature correction storage means for storing the correction amount corresponding to each representative value in association with the representative value;
Correction value selecting means for selecting a correction amount corresponding to the representative value specified by the temperature specifying means from the transmission output temperature correction storage means;
Initial value holding means for holding the value of the transmission output level at a predetermined reference temperature;
Means for generating the digital signal from the correction amount selected by the correction value selection means and the value held by the initial value holding means;
The transmitter according to claim 1. The temperature judgment value storage means holds a threshold temperature representing the boundary of each temperature range,
The temperature specifying means is configured to sequentially compare the temperature represented by the detection signal with the threshold temperature to determine a temperature range to which the temperature belongs.
The transmitter according to claim 3. The temperature compensation processing means includes
It is configured to perform temperature compensation of the transmission output level by multiplying the digital signal and the digital modulation signal.
The transmitter according to claim 1. The first means comprises a diode;
The detection signal is configured to be generated based on a forward voltage that changes depending on the temperature dependence of the diode.
The transmitter according to any one of claims 1 to 5. The first means comprises a thyristor;
Based on the voltage that changes due to the temperature dependence of this thyristor, it is configured to generate the detection signal,
The transmitter according to any one of claims 1 to 5. Means for detecting a temperature of the device itself, generating a detection signal representing the detected temperature, means for generating a digital modulation signal converted into an RF signal, and a transmission output level of the RF signal corresponding to the temperature A transmission unit that stores a correction amount and performs temperature compensation of a transmission output level, and a unit that generates an RF signal output from a predetermined antenna based on the corrected digital modulation signal A method performed by a machine,
The processing means is
Selecting a correction amount according to the temperature represented by the detection signal;
Generating a digital signal corresponding to the selected correction amount;
Compensating the temperature of the transmission output level of the RF signal based on the digital modulation signal after the digital signal processing by performing digital signal processing on the generated digital signal and the digital modulation signal. . In a computer having a transmitter in which the transmission output level of the RF signal varies in accordance with a change in ambient temperature,
Means for detecting the temperature of the machine and generating a detection signal representing the detected temperature;
Means for generating a digital modulation signal which is converted into the RF signal;
Stores the correction amount of the transmission output level corresponding to the temperature, and performs digital signal processing on the digital signal based on the correction amount corresponding to the temperature represented by the detection signal and the digital modulation signal, thereby performing post-digital signal processing. Means for performing temperature compensation of the transmission output level of the RF signal based on the digital modulation signal of
Means for generating an RF signal based on a digital modulation signal subjected to digital signal processing for temperature compensation of a transmission output level;
Computer program to form.

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