JP3278311B2 - Data transceiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmitting / receiving apparatus for transmitting data in a time-division manner using the same frequency.

[0002]

2. Description of the Related Art FIG. 14 shows a conventional example of a data transmitting / receiving apparatus using a so-called TDD (Time Division Duplex) communication system for transmitting data in a time-division manner using the same frequency. In FIG. 14, reference numeral 1 denotes an antenna, 2 denotes a transmission / reception switch for switching between transmission and reception, 3 denotes a local oscillator, 101 denotes a transmission unit, and 102 denotes a reception unit. Further, in the transmitting section 101, 160 is a modulator, 4 is a carrier generator, 5 is a first mixer, 6 is a band-pass filter, 7 is a high-frequency amplifier, and 8 is a band-pass filter in the receiving section 102. Is a high frequency amplifier, 10 is a second mixer, 121
Is a bandpass filter, 122 is an amplifier, and 123 is a demodulation circuit.

[0003] First, the operation of the transmission unit 101 during transmission will be described.
I do. Frequency f output from carrier generator 4_cTransport
Wave S1 is modulated with the transmitted data in modulator 160.
And the intermediate frequency f_c Modulators 160 as modulated signals of
Is output. This modulated signal is input to the first mixer 5.
Local oscillation signal (frequency
f _a) And frequency conversion. Output signal of mixer 5
Frequency f0 (f0 = f_a+ F_c ) Signal
The signal passes through the band-pass filter 6 and is amplified by the high-frequency amplifier 7.
And a transmission / reception switch 2 connected to the transmission unit.
And is radiated to the space via the antenna 1.

[0004] Next, the operation of the receiving unit 102 during reception will be described. The signal received by the antenna 1 is sent to the band-pass filter 8 via the transmission / reception changeover switch 2 connected to the receiving section, and has a predetermined frequency band (center frequency f0).
Is input to the high-frequency amplifier 9 and amplified. The signal amplified by the RF amplifier 9 is mixed with the output signal of the local oscillator 3 (frequency f _a) at the second mixer 10 of, and is converted into a signal of a further center frequency of the intermediate frequency f _c.
This signal is input to the bandpass filter 121, an intermediate frequency f _c a predetermined band of the received signal with the center frequency (hereinafter, referred to as the intermediate signal S2) is passed through a bandpass filter 121. The intermediate signal S2 that has passed through the band-pass filter 121 is further amplified by the amplifier 122 and then demodulated by the demodulation circuit 123.

[0005] Since it takes time to start up the carrier generator 4, it is necessary to operate the carrier generator 4 also at the time of reception if the switching time between transmission and reception is short. However, the intermediate frequency f output from the carrier generator 4
_Since the level of the carrier S1 of _c is much higher than the level of the intermediate signal S2 in the receiver 102, if the carrier generator 4 is operating even during reception, the carrier S1 leaking from the carrier generator 4 will be transmitted to the receiver 102. It is possible that the signal may jump in, pass through the band-pass filter 121, and interfere with the intermediate signal S2 in the amplifier 122 to deteriorate the received signal sensitivity.

As a method of solving such a problem, the oscillation frequency of the carrier generator 4 and frequency higher than the intermediate frequency f _c, stop a divider for dividing the output, the operation of the frequency divider during reception the switch that, provided between the carrier generator 4 and the modulator 160, there is a method that not generate a carrier wave of frequency f _c from the transmitting unit 101 at the time of reception (e.g., JP-4-240924).

[0007]

However, the conventional method as described above requires a new frequency divider and switch, which is disadvantageous in terms of cost and circuit scale. Further, there is a problem have the realized as intermediate frequency f _c is the high frequency becomes difficult.

The present invention has been made in consideration of such a problem of a conventional data transmitting / receiving apparatus, and does not require a frequency divider or a switch for switching the operation of the frequency divider, and a carrier leaks from a transmitter to a receiver. It is an object of the present invention to provide a data transmission / reception device capable of eliminating the deterioration of reception signal sensitivity.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a data transmitting / receiving apparatus for transmitting / receiving data in a time-division manner using the same frequency, a carrier generator for outputting a carrier, and an output from the carrier generator. A transmitting unit having a modulator that outputs a modulated signal obtained by digitally modulating a carrier using transmission data, and only a frequency component of a partial band that does not include the frequency of the carrier among the frequency components of the received modulated signal. A data transmission / reception apparatus comprising: at least one band-pass means for extracting, at least one detector for detecting an output signal of the band-pass means, and a receiving unit having a decoder for decoding the detected signal.

[0010]

According to the present invention, in the receiving section, only the frequency component of a partial band that does not include the frequency of the carrier wave is extracted from the frequency components of the modulated signal received by the band-pass unit, and the detector detects the frequency component of the band-pass unit. Since the output signal is detected, deterioration of the reception quality due to the carrier leaking from the transmission unit to the reception unit is eliminated.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing embodiments thereof.

FIG. 1 is a block diagram of a data transmitting / receiving apparatus according to a first embodiment of the present invention. In FIG. 1, 1
Is an antenna, 2 is a transmission / reception switch for switching between transmission and reception, 19 is a transmission unit, and 20 is a reception unit. In the transmission section 19, 16 is a modulator, and 4 is a carrier generator. In the receiving unit 20, reference numeral 21 denotes a band pass unit, 30 denotes an amplifier, 22 denotes a detector, 25 denotes a clock regenerator, and 23 denotes a decoder. FIG. 2 is a schematic diagram showing a relationship between a spectrum and a passband indicating a difference between the intermediate signal of the present embodiment and the intermediate signal of the receiving unit described in the section of "Prior Art". FIG. 3 is a block diagram showing a configuration example of the modulator 16, in which 11 is a differential encoder, 12 is a phase modulator, 13 is a spread modulation signal generator, 14 is a spread modulation multiplier, and 15 is a clock. Generator. FIG. 4 is a block diagram showing an example of the configuration of the detector 22. Reference numeral 221 denotes a symbol delay unit;
Is a multiplier, and 223 is a low-pass filter. FIG.
6 is a signal waveform diagram (baseband waveform is shown for convenience) of each unit of the apparatus in FIG. 1, and FIG. 6 is a block diagram showing a configuration example of the band-pass unit 21.

Next, the operation of the data transmitting / receiving device of the first embodiment will be described with reference to the drawings.

First, the operation at the time of transmission will be described. As shown in FIG. 3, data d which is a bit string is taken into a modulator 16 in synchronization with a symbol clock CK, is differentially encoded by a differential encoder 11, and is then encoded by a phase modulator 12.
Modulates a carrier S1 of frequency f _c which is output from the carrier generator 4, to obtain an intermediate frequency f _c, the primary modulation signal p is two-phase modulated wave symbol period T. The primary modulation method includes
For example, (differential) phase modulation such as 2, 4, or 8 phases is used. The spread modulation signal generator 13 outputs the symbol clock CK
To generate a spread modulation signal q having the same period as the above. The spread modulation signal q is a pseudo random pulse waveform having a constant amplitude generated by a pseudo random sequence. The spread modulation multiplier 14 multiplies the primary modulation signal p by the spread modulation signal q to obtain a spread spectrum signal a. Hereinafter, the operation up to this point will be described in more detail, taking as an example the case where the primary modulation method is two-phase differential phase modulation.

In the transmitter 19, the m-th transmission data d _m (± 1, binary) is taken in synchronism with the symbol clock CK having a period T, and is differentially encoded by the differential encoder 11. After that, the signal is modulated by the phase modulator 12, and as its output, a primary modulation signal p which is a two-phase modulation wave with a symbol period T is obtained. The spread modulation signal generator 13 generates a spread modulation signal q having the same cycle as the symbol clock CK in synchronization with the symbol clock CK. The spread modulation signal q is, for example, a pseudo random pulse waveform having a constant amplitude generated by a pseudo random sequence. The spread modulation multiplier 14 multiplies the primary modulation signal p by the spread modulation signal q to obtain a spread spectrum signal a.

Now, the data after differential encoding is represented by δ _m (±
1 and 2)

[0017]

## EQU1 ## It can be expressed as d _m = δ _m × δ _m-1 . Therefore, the frequency of the output carrier of the transmission carrier wave generator 4 as f _c, if the real part of the Re [...], the spread spectrum signal a to be transmitted is represented by the following equation.

[0018]

In Equation 2] a (t) = Re [δ m · q (t) · expj (2πf c t)] FIG. 5 (a), the primary modulation signal p, spreading modulation signal q, and spread spectrum signal a time The waveform is shown. However, for the primary modulation signal p and the spread spectrum signal a, the baseband waveform is illustrated for convenience. The spread spectrum signal a is radiated into space via the transmission / reception change-over switch 2 and the antenna 1 connected to the transmission section.

Next, the operation at the time of reception will be described. Receiving
In the section 20, first, the spectrum expansion received by the antenna 1 is performed.
The band of the scattered signal a is limited by the band-pass
Number f _cExtract the partial band signal that does not contain
Let it be signal b.

FIG. 2 is a schematic diagram showing a spectrum representing a difference between the intermediate signal b of the present embodiment and the intermediate signal S2 in the receiving section of the conventional data transmitting / receiving apparatus. The intermediate signal b in the present embodiment is a signal that has passed through the band B1 or B2 in FIG. That is, the major difference between the intermediate signal b in the receiving portion of the intermediate signal S2 and the embodiment of the receiver portion of the conventional example, although the band of the intermediate signal S2 of the conventional example are the frequency f _c of the carrier wave S1 is free On the other hand, the intermediate signal b of the present embodiment
The band has become a partial band of the spread spectrum signal a received is that does not contain the carrier frequency f _c of the carrier generator 4 into the band. Therefore, even if the carrier S1 (frequency f _c ) output from the carrier generator 4 leaks from the transmitter 19 to the receiver 20,
The intermediate signal b of the present embodiment is not affected by this.

Thereafter, the intermediate signal b is amplified by the amplifier 30 and then input to the detector 22, where it is detected by the detector 22 to obtain a detected signal c. As the detector 22, for example, a delay detector 22 as shown in FIG. 4 is used.

FIG. 5B is a waveform diagram showing an example of a signal waveform of each part of the receiving device 20. The baseband waveform of the spread spectrum signal a has
If the primary modulation signals have the same phase, they have the same shape,
When the phase of the primary modulation signal is opposite, the shape is inverted. Then, the intermediate signal b, which is the output of the band pass means 21, is

[0023]

Equation 3] b (t) = Re [δ m · q '(t) · expj (2πf c t)] and expressed (δ _m = ± 1). The baseband waveform of the intermediate signal b is band-limited by the band-passing means 21 to have a waveform considerably different from the shape of the spread spectrum signal a (that is, q representing the complex envelope in (Equation 2)). Is replaced by q ′ in the case of band limitation in (Equation 3)). In each symbol section, when the phase of the primary modulation signal is equal, the shape is almost the same. a shape sign is inverted when the phase is reversed ((as can be seen from several 3), b is the sign of [delta] _m, positive and negative of the waveform is inverted). Strictly speaking, in the vicinity of the boundary between adjacent symbols, the shape of the intermediate signal is not exactly the same because of the influence of the adjacent symbol, causing intersymbol interference. If it is large, the intersymbol interference is small, so it does not matter much.

Next, the delay detector 22 shown in FIG. 4, first, the symbol delay unit 221, only the symbol period T, the intermediate signal b is delayed to obtain a delayed intermediate signal b _d.
Note that the spread modulated signal q is a repetitive waveform with a period T, and approximately q 'is also a repetitive waveform with a period T.

[0025]

Equation 4] _{b d (t) = b (} t-T) = Re [δ m-1 · q '(t) · expj (2πf c t) · expj (-2πf
_c T)]. now,

[0026]

## EQU5 ## By accurately determining T or by adjusting the phase of the output signal of the symbol delay unit 221 so as to satisfy expj (-2πf _c T) = 1, the delay intermediate signal b _d eventually becomes ,

[0027]

[6] b _d (t) = a _{Re [δ m-1 · q} '(t) · expj (2πf c t)]. Of the output of the multiplier 222, the low-frequency component extracted by the low-pass filter 223, that is, the detection signal c performs multiplication of (Equation 3) and (Equation 6), and expj ( except the section components 4πf _c t), by using equation (1),

[0028]

Equation 7] _{c (t) = δ m ·} δ m-1 {Re [q '(t)]} 2 = d m {Re
[q ′ (t)]｝ ² is obtained. (Equation 7) shows that the data is decoded by determining the polarity of the detection signal c.

FIG. 5B schematically shows the state of the detection process. That is, when there is no change in phase from the previous symbol, a pulse having the same shape is multiplied to generate a positive pulse. When the phase is inverted from the previous symbol, a pulse having a shape which is inverted is also multiplied. This produces a negative pulse. Accordingly, the detection signal c becomes negative and positive pulses depending on whether or not the phase is inverted. The clock regenerator 25 generates a reproduced symbol clock from the detected signal c, and by using the timing, the decoder 23 sequentially samples and identifies the detected signal c, and then, based on the sign polarity of the identification point, If it is positive, it is determined to be 1, and if it is negative, it is determined to be -1, and the decoded data sequence d' _m is output.

The band-pass means 21 may be composed of only a band-pass filter or, as shown in FIG. 6, a band-pass filter 211 and a frequency mixer 212.
And the local oscillator 213. In this case, the input signal is converted by the frequency mixer 212 into a frequency band having a difference from the local oscillation signal which is the output of the local oscillator 213, and then band-limited by the band-pass filter 211 to be frequency-converted. Only a part of the frequency component of the signal a is extracted and output as the intermediate signal b.

Now, the oscillation frequency of the local oscillator 213 is set to f
_{If L} , (Equation 3) becomes (Equation 8),

[0032]

B (t) = Re [δ _m · q ′ (t) · expj {2π
(f _c −f _L ) t}] (Equation 4) becomes (Equation 9),

[0033]

Equation 9] _{b d (t) = b (} t-T) = Re [δ m-1 · q '(t) · expj {2π (f c -f L) t} · expj {-2
π (f _c -f _L ) T}] (Equation 5)

[0034]

Equation 10] so as to satisfy the _{expj {-2π (f c -f L} ) T} = 1, or precisely define the T, or by adjusting the phase of the output signal of the symbol delay unit 221, after all, (Equation 6) representing the delayed intermediate signal b _d is (Equation 1)
1).

[0035]

Equation 11] _{b d (t) = Re [} δ m-1 · q '(t) · expj {2π (f c -f L) t}] Similarly, in the output of the multiplier 222, low-pass The low frequency component extracted by the filter 223, that is, the detection signal c is subjected to the multiplication of (Equation 8) and (Equation 11), and the expj {4π (f _c -f _L ) t} of the harmonic component is obtained. Except for the component term, by using (Equation 1), the result of (Equation 7) is obtained. Similarly, it can be seen that judgment data can be obtained by judging the polarity of the detection signal c. (Equation 1)
0), k is an integer,

[0036]

F _L = f _c −k × (1 / T)
(K is an integer) of the results obtained, the oscillation frequency f _L of the local oscillator 213 must be frequency separated by an integral multiple of the frequency spacing of the symbol rate 1 / T from the frequency f _c of the carrier wave S1.

For example, the oscillation frequency f of the local oscillator 213
_{If L} is (Equation 13),

[0038]

F _L = f _c −n × (1 / T)
(N is an integer) The spread spectrum signal a is converted into a spread spectrum signal having a center frequency n / T. Therefore, here, for example, the center frequency is set to (n
+2) / T and a pass bandwidth of 2 / T, equivalently, the intermediate signal b becomes the spread spectrum signal a
Becomes a signal of a partial frequency component (bandwidth 2 / T) of
Does not include the component of the frequency f _c is the frequency component of the intermediate signal b.

As described above, in the data transmitting / receiving apparatus of the present embodiment, the spread spectrum signal a
Among the frequency components of, without equal signal components to the frequency f _c of the carrier wave S1 output from the carrier generator 4 takes out the other partial band signals to generate an intermediate signal b, the intermediate signal Detection and decoding can be performed using b. Therefore, the carrier S having a higher level than the intermediate signal b
1 also (frequency f _c) is leaked from the carrier generator 4 does not interfere with the intermediate signal b to the carrier S1 is passed through the band-pass means 21. From this, in this example,
Since it is not necessary to suppress the carrier S1 leaking from the carrier generator 4 from jumping into the bandpass means 21, it is not necessary to use a frequency divider or a switch as described in the section of "Prior Art", and the circuit can be realized. It will be easier.

In the above embodiment, the case of two-phase modulation has been described. However, the detection process is the same in the case of multi-level modulation such as four-phase and eight-phase. The difference is that the configuration of the delay detector 22 is two systems including the orthogonal axis, and the decoder 23 performs identification and determination of the detection signal c to obtain a determination symbol data sequence, and then performs parallel-serial conversion. This is to output a decoded data sequence d' _m which is a bit sequence (for example, WRBennet, JRDavey, "Data Transmission", Latex).

In the above embodiment, the spread modulated signal q is a pseudo random pulse waveform having a constant amplitude generated by a pseudo random sequence. However, the present invention is not limited to this. A chirp signal as shown may be used. FIG. 8 shows a waveform in the detection process when the chirp signal is used. That is, when the pass band of the band pass means 21 is B1 in FIG.
The intermediate signal and the detected signal are respectively b1 and c in FIG.
1 and the pass band of the band pass means 21 is B2 in FIG. 8A, the intermediate signal and the detection signal
B2 and c2 in (b).

Further, in the above embodiment, the period of the spread modulation signal q is equal to the symbol period T of the primary modulation signal p, but is assumed to be 1 / n (n is a natural number) of the symbol period T of the primary modulation signal p. Alternatively, the symbol detection may be performed n times (n is a natural number) the symbol period T of the primary modulation signal p, and the delay detection may be performed using the symbol delay unit 221 having a delay time n times the symbol period T. .

FIG. 9 is a block diagram of a data transmitting / receiving apparatus according to a second embodiment of the present invention. In FIG. 9, 3
Is a local oscillator, 190 is a transmitting unit, 200 is a receiving unit, 5 is a first mixer, 6 is a band-pass filter, 7 is a high-frequency amplifier, and 7 is a high-frequency amplifier.
8 is a band pass filter, 9 is a high frequency amplifier, 10 is a second
Is a mixer. In addition, the components denoted by the same reference numerals as those in the embodiment of FIG. 1 in FIG. 9 are the same as those in the embodiment of FIG. Hereinafter, a second embodiment of the present invention will be described with reference to FIG.

The transmitting section 190 is configured to perform frequency conversion on the spread spectrum signal a output from the transmitting section 19 in FIG. That is, the transmission unit 190 at the time of transmission, the spread spectrum signal obtained in the same manner as the transmitter 19 of FIG. 1 a (intermediate frequency f _c)
Is input to the first mixer 5 and mixed with the local oscillation signal (frequency f _a ) of the local oscillator 3 to obtain the frequency f 0 (f 0 = f
After being frequency converted to _a + f _c), passing through the band-pass filter 6 is amplified by the RF amplifier 7 is radiated into space through the transmitting and receiving changeover switch 2 and the antenna 1 connected to the transmitting side.

On the other hand, the receiving section 200
The spread-spectrum signal of frequency f0
f_c Is converted into a spread spectrum signal a of FIG.
Is configured to perform detection and demodulation in the same manner as the receiving unit 20 of FIG.
It was a thing. That is, at the time of reception,
0: Spread spectrum signal received by antenna 1
After the (center frequency f0) is amplified by the high frequency amplifier 8,
Pass through the band-pass filter 9 and input to the second mixer 10
The local oscillation signal (frequency f _a ) And mixed
The intermediate frequency f_c(F_c= F0-f_a) To frequency conversion
Thus, a spread spectrum signal a is obtained. Figure 1 reception
Like the unit 20, the spread spectrum signal a
Input to the pass filter 21,
In the same manner as in the first embodiment, the center frequency f_c Excluding
Only the partial frequency components are extracted and the intermediate signal b is obtained.
It is. Then, from the intermediate signal b, the first embodiment is performed.
Through the detection and decoding processes in the same manner as described in
Data is obtained. Therefore, also in the receiving unit 200,
Frequency f leaking from carrier generator 4_cCarrier S1
Without passing through the band-pass filter 21, the carrier S1
Does not cause reception sensitivity degradation.

As described above, according to the second embodiment,
Carrier S1 leaking from carrier generator 4 to receiving section 200
Since there is no reception sensitivity degradation due to (frequency f _c), the same intermediate frequency can be used with a transmitter 190 and receiver 200. Therefore, a local oscillation signal for converting the spread spectrum signal a in the transmission section 190 from the intermediate frequency f _c the frequency f0, for converting the spread spectrum signal from the frequency f0 received by the receiver 200 to an intermediate frequency f _c The local oscillation signal can have the same frequency. Therefore, this embodiment has an advantage that the common local oscillator 3 can be used for the frequency conversion of the transmission unit 190 and the reception unit 200.

FIG. 10 is a block diagram of a data transmitting / receiving apparatus according to a third embodiment of the present invention. 10, reference numeral 191 denotes a transmitting unit, 201 denotes a receiving unit, 17 denotes a packet assembler, 21A to 21B denote band-pass means, 28A to 2
8B is a demodulation unit, 26A to 26B are unique word detectors, 27A to 27B are packet extractors, 29A to 29B
Is an error detector, and 24 is a decision selector. FIG. 11 is a block diagram illustrating a configuration example of the demodulation units 28A to 28B.
30 is an amplifier, 22 is a detector, 25 is a clock regenerator,
Reference numeral 23 denotes a decoder, which is the same as that used in the first and second embodiments.

FIG. 12 shows an example of the code structure of a data packet output from the packet assembler 17.
FIG. 12A illustrates an example of a data packet observed in a determination data string output from the demodulation units 28A to 28B.
(B) The operation will be described below with reference to FIG. 13 showing the outline of the spectrum of the signal of each section.

First, the operation at the time of transmission will be described. In the present embodiment, the configuration and operation of each unit of the transmission unit 191 are almost the same as those of the transmission unit 190 of the second embodiment shown in FIG. 9, but a packet assembler 17 is added, and And a burst-like spread spectrum signal a corresponding to each of the packets
Output to the mixer 5 of FIG. In other words, the transmission data is first divided for each predetermined number of bits,
(A) shows, as an example, information data 93, and data packets 61 to 64 are formed by adding a preamble 91, a unique word 92, and error detection bits 94. As in the first embodiment, the data packets 61 to 64 are taken into the modulator 16 in synchronization with the symbol clock CK, become a burst-like primary modulation signal p corresponding to each packet, and become a spread modulation signal q To obtain a spread spectrum signal a. This spread spectrum signal a
Is frequency-converted and amplified in the same manner as in the second embodiment, and is then radiated into space via the transmission / reception change-over switch 2 and the antenna 1 connected to the transmission unit.

Since the steep rise and fall of the burst causes an increase in the transmission spectrum width, a ramp waveform whose envelope changes smoothly may be added to the leading and trailing edges of the burst. Unique word 9
Reference numeral 2 denotes a fixed bit pattern sequence inserted to find a corresponding data packet in a decoding process in the receiving unit 201, as described later. On the other hand, the error detection bit 94
Is a variable bit pattern sequence inserted in the receiving unit 201 to check whether or not a bit error has occurred in the information data 93 and the error detection bit 94 itself. In practice, the error detection bit 94 uses a parity code or a CRC (Cyclic Redundancy Check) code.

Next, the operation at the time of reception will be described. The configuration and operation of the receiving unit 201 from the antenna 1 to the second mixer 10 are the same as in the second embodiment shown in FIG. the description below processing of the spread spectrum signal a the intermediate frequency f _c the center frequency that.

The spread spectrum signal a is first band-limited by the band-pass means 21A to 21B to become an intermediate signal b. FIG. 13 illustrates the outline of the spectrum of the received spread spectrum signal a and the case where the band pass means 21A to 21B can take four bands (B1 to B4).

As shown in FIG. 13, the band pass means 21A
To 21B, the first embodiment and the second
As in the embodiment, the carrier S generated by the carrier generator 4 is
1 of frequency f _c is not included. Therefore, also in this embodiment as in the first embodiment and the second embodiment, the carrier S1, leaking from the carrier wave generator 4 (frequency f _c) is receiver 2
Even if the signal leaks to 01, the received signal sensitivity does not deteriorate.

Each of the band pass means 21A to 21B is constituted by a band pass filter, and each corresponds to all or a part of the pass bands B1 to B4. The number of pass bands is not limited to four as shown in FIG. 13, but may be two or more. Similarly, as shown in FIG. 10, the number of band-pass means 21A to 21B may be two or more, and a typical example includes two cases.

The intermediate signal b thus obtained is detected and decoded in the demodulators 28A to 28B in the same manner as in the first embodiment, and is output from the demodulators 28A to 28B as a decision data sequence d' _m. Is done.

FIG. 12A shows the judgment data sequence d' _m .
The data packets 61 ′ to 64 ′ of FIG. 12B having the same structure and corresponding to the data packets 61 to 64 of FIG. The unique word detectors 26A to 26B collate the determination data string d' _m with the fixed pattern of the unique word as needed, and output a frame signal when a match is detected. The packet extractors 27A to 27B make the information data 93 'and the error detection bit 9 based on the timing of the frame signal.
A decoded data packet 95 'composed of 4' is extracted and delivered to the error detectors 29A to 29B. Error detector 29A-
29B detects a bit error in the decoded data packet 95 'based on the error detection bit 94' and delivers the result to the decision selector 24, and also includes the information data 93 'in the decoded data packet 95'. Judgment selector 2
Hand over to 4. The decision selector 24 selects and joins only the information data 93 ′ of the system in which no bit error has been detected, and outputs it as decoded data of the final output of the receiving unit 201.

[0057] Thus, according to the configuration of this embodiment shown in FIG. 10, the frequency f even when the carrier S1 is leaked from the carrier generator 4 to the receiver 201 of _c, the carrier S1 is bandpass means Because it does not pass through 21A-21B,
Packet data transmission / reception can be performed without receiving signal sensitivity deterioration due to leakage of the carrier wave S1.

[0058] Incidentally, if only for transmitting and receiving packet data from the carrier generator 4 of the carrier S1 of the frequency f _c without the degradation of the received signal sensitivity according to leakage of the reception section 201, in FIG. 10, Spectrum The system for processing the spread signal a is only one system surrounded by a dotted line 300 in FIG.
Although only one signal processing system is required and the decision selector 24 is not necessary, as shown in FIG. 10, the following effects can be obtained by providing a plurality of processing systems for the spread spectrum signal a and providing the decision selector 24. Occurs.

As shown in FIG. 13, when an interference wave j is added on the transmission line, according to the apparatus of this embodiment, the partial bands B1 to B4 of the transmitted spread spectrum signal a are transmitted.
Only band pass means 21A to 21B are provided, so that only band pass means 21A to 21B are provided in the example of FIG.
Is set in the pass band B1, the intermediate signal b input to the detector of that system is not affected by the interference wave j, and normal reception is performed. Therefore,
In other systems, even if reception is not performed normally and the error detector detects a bit error, as described above, if at least one system has been able to avoid the influence of the interfering wave j, the system The error detector does not detect a bit error, and the decision selector 24 selects the information data 93 'of the system and outputs it as decoded data, so that normal reception is continued.

As in the case of the first embodiment, the band-pass means 21A and 21B are similar to the band-pass means 21 shown in FIG.
2 and the local oscillator 213. However, in this case, it was expressed in the first embodiment (Equation 12).
From relationship, the oscillation frequency f _L of the local oscillator 213 should be frequency separated by an integral multiple of the frequency spacing of the symbol rate 1 / T from the frequency f _c. Local oscillator 21
Reference numeral 3 denotes a PLL (Phase Locked Loop) synthesizer which varies the frequency of the local oscillation signal at a frequency interval that is an integral multiple of the symbol rate 1 / T, or the local oscillator of each of the band-pass means 21A to 21B. Reference numeral 213 is for generating a local oscillation signal having a frequency different by this frequency interval. Equivalently, by changing the frequency of the local oscillation signal, it is possible to extract, as the intermediate signal b, the component of the original spread spectrum signal a having a different frequency component. When the center frequencies of the intermediate signals of the band-pass units 21A to 21B are selected to be the same, and the frequencies of the local oscillation signals are changed to obtain different pass bands, the respective band-pass filters 211 and the demodulation units 28A to 28B are used.
28B, the same one can be used, and the amplifier 30 and the detector 22 inside the demodulation units 28A to 28B shown in FIG.
Has the advantage of being easy to realize because it is only necessary to guarantee operation in a relatively narrow frequency range equivalent to a pass band.

[0061]

As apparent from the above description, according to the present invention, the receiving section includes a portion of the frequency component of the received modulated signal which does not include the frequency of the carrier output from the carrier generator of the transmitting section. At least one band-pass means for extracting only frequency components in a specific band and at least one detector for detecting an output signal of the band-pass means, a frequency divider and a switch for switching the operation of the frequency divider are required. However, there is an advantage that deterioration of received signal sensitivity due to leakage of a carrier wave from the transmission unit to the reception unit can be eliminated.

[Brief description of the drawings]

FIG. 1 is a block diagram of a data transmitting / receiving apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a spectrum of a signal in a receiving unit according to the first embodiment.

FIG. 3 is a block diagram illustrating a configuration example of a modulator according to the first embodiment.

FIG. 4 is a block diagram illustrating a configuration example of a detector according to the first embodiment.

FIG. 5A is a diagram showing an example of a signal waveform of each unit of a transmission unit in the first embodiment; FIG. 5B is a diagram showing an example of a signal waveform of each unit of a reception unit; It is.

FIG. 6 is a block diagram showing a configuration example of a band-pass unit in the first embodiment.

FIG. 7 is a diagram illustrating an example of a signal waveform of each unit of the transmission unit when the spread modulation signal is a chirp signal in the first embodiment.

FIG. 8A is a diagram schematically illustrating a spectrum of a signal in a receiving unit when a spread modulation signal is a chirp signal in the first embodiment, and FIG. 8B is a diagram illustrating the case. FIG. 3 is a diagram illustrating an example of a signal waveform of each unit of a receiving unit.

FIG. 9 is a block diagram of a data transmission / reception device according to a second embodiment of the present invention.

FIG. 10 is a block diagram of a data transmitting / receiving device according to a third embodiment of the present invention.

FIG. 11 is a block diagram illustrating a configuration example of a demodulation unit according to the third embodiment.

FIG. 12A is a diagram showing an example of a code configuration of a transmission data packet in the third embodiment, and FIG.
FIG. 4 is a diagram illustrating an example of a data packet observed in the determination data sequence.

FIG. 13 is a diagram schematically illustrating a spectrum of a signal in a receiving unit according to the third embodiment.

FIG. 14 is a block diagram of a conventional data transmitting / receiving device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 antenna 2 transmission / reception switch 3 local oscillator 4 carrier generator 5 first mixer 10 second mixer 16, 160 modulator 17 packet assembler 19, 101, 190, 191 transmitter 20, 102, 200, 201 Receiving unit 21, 21A to 21B Bandpass means 22 Detector 23 Decoder 24 Judgment selector 26A to 26B Unique word detector 27A to 27B Packet extractor 28A to 28B Frame error detector 29A to 29B Error detector

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-372233 (JP, A) JP-A-4-240924 (JP, A) JP-A-6-350501 (JP, A) JP-A-6-350501 104865 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 1/54 H04B 1/707 H04L 27/227

Claims (7)

(57) [Claims] 1. A data transmitting and receiving apparatus for transmitting and receiving data in a time-division manner using the same frequency, comprising: a carrier generator for outputting a carrier; and a carrier output from the carrier generator, using transmission data. A transmitter having a modulator for outputting a digitally modulated signal, and at least one band-pass means for extracting only a frequency component of a partial band not including the frequency of the carrier wave from frequency components of the received modulated signal And a receiving unit having at least one detector for detecting an output signal of the band-pass unit and a decoder for decoding the detected signal. 2. The transmitting section has a first mixer for converting a frequency band of the modulated signal, and the receiving section has a second mixer for converting a frequency band of the received signal. 2. The data transmitting / receiving apparatus according to claim 1, wherein both the first mixer and the second mixer include a local oscillator for supplying a local oscillation signal for frequency conversion. 3. The transmitting section has a spread modulation signal generator,
3. The data transmission / reception device according to claim 1, wherein a spread spectrum signal obtained by multiplying the digitally modulated primary modulation signal by a spread modulation signal having a band wider than the primary modulation signal is output. 4. The data transmitting / receiving apparatus according to claim 3, wherein the spread modulation signal is a chirp signal obtained by repeatedly sweeping a frequency of a sine wave in each cycle. 5. The transmission data is packet data including at least a unique word and an error detection bit, and the receiving unit generates at least one clock for generating a reproduction clock from at least one detection signal output from the detector. A regenerator, at least one decoder that outputs a judgment data sequence from the detection signal and the reproduction clock, and a head of the decoded data packet by detecting the unique word from at least one judgment data sequence. At least one unique word detector to be found, at least one packet extractor for extracting each of the decoded data packets from the determination data sequence based on a frame signal output from the unique word detector, and the error detection bit. Using the decrypted data packet At least one error detector for detecting a bit error in the packet, and obtaining the decoded data from the decoded data packet determined by the error detector to have no bit error. Item 5. The data transmitting / receiving device according to item 3 or 4. 6. The digital modulation is a differential phase modulation, wherein the period of the spread modulation signal is an integral multiple or 1 / integral of the symbol period of the primary modulation signal, and the detector detects the intermediate signal and the intermediate signal. The data transmission / reception device according to any one of claims 3 to 5, wherein the data transmission / reception device is a delay detector that obtains a detection signal by multiplying the primary modulation signal by a delay signal delayed by an integer multiple of the symbol period. 7. The band pass means includes: a frequency mixer; a local oscillator for supplying a local oscillation signal to the frequency mixer;
A band-pass filter for extracting only a signal component of a partial band of the output of the frequency mixer converted into a frequency band having a difference from the frequency of the local oscillation signal, and Or changing the frequency of the local oscillation signal at a frequency interval of an integer multiple of the symbol period excluding the frequency of the carrier, excluding the frequency of the symbol. 7. The data transmitting / receiving device according to claim 6, wherein an oscillator is used.