KR20010008695A - Dual mode mobile terminal shared intermediate frequency - Google Patents

Abstract

PURPOSE: A dual mode mobile terminal for sharing an intermediate frequency(IF) is provided to share a personal communication services(PCS) IF processor and an international mobile telecommunications(IMT)-2000 IF processor for sharing an IMT-2000 IF and a PCS IF. CONSTITUTION: A first mixer(35) uses a reception international mobile telecommunications(IMT)-2000 radio frequency(RF) while operating in an IMT-2000 mode, and generates an IMT-2000 intermediate frequency(IF) for sharing with an IF in a personal communication services(PCS) mode. A second mixer(36) uses the reception PCS RF while operating in the PCS mode, and generates a PCS IF for sharing with the IMT-2000 IF. A reception band selecting switch(37) selectively switches an output of the first mixer(35) to a first band pass filter(38) and a second band pass filter(39) according to a bandwidth control signal output from a modem of the dual mode mobile terminal, and switches an output of the second mixer(36) to the second band pass filter(39). The first band pass filter/second band pass filter(38.39) are selected by the reception band selecting switch(37), and respectively performs a corresponding band pass filtering to a reception IF.

Description

Dual mode mobile terminal shared intermediate frequency

The present invention relates to a dual mode mobile terminal that can be used in an IMT-2000 (International Mobile Telecommunications 2000) system and a Personal Communication Service System (PCS). In particular, the present invention relates to a dual mode mobile terminal capable of processing both PCS intermediate frequency and IMT-2000 intermediate frequency by sharing an intermediate frequency of PCS with an IMT-2000 intermediate frequency.

The PCS service and IMT-2000 are implemented by implementing a device that can process IMT-2000 service signals in the mobile terminal operating in the PCS operation mode to provide the PCS service currently in use and to provide the IMT-2000 service that will be commercialized in the future. Ensure that all services are provided.

FIG. 1 shows a block configuration of such a dual mode mobile terminal. Referring to FIG. 1, reference numeral 1 denotes a service mode according to an operation mode control of a modem (not shown in FIG. This switch selects. Reference numeral 2 is an IMT-2000 mode duplexer which simultaneously transmits and receives an IMT-2000 signal, transmits a transmitted signal to the switch 1, and transmits a received signal to the IMT-2000 RF processor 4. 3 is a PCS mode duplexer which simultaneously transmits and receives a PCS signal, transmits a transmitted signal to the switch 1 and a received signal to the PCS RF processor 5.

Reference numeral 4 is an IMT-2000 RF processor which inversely converts a signal received to be operated in the IMT-2000 mode by the switch 1 into a radio frequency (RF), and 6 is an IMT-2000 RF processor 4. The mixer generates an intermediate frequency (IF) signal by mixing the output signal with the local oscillator output. 8 is a band pass filter (BPF) which passes only a frequency of 5 MHz band among the intermediate frequencies generated by the mixer 6, and 10 is an IMT that processes the intermediate frequency passed by the band pass filter 8. -2000 Receive IF processing unit.

5 is a PCS RF processing unit for RF inverse conversion of the signal received to operate in the PCS mode by the switch 1, 7 is a middle by mixing the signal output from the PCS RF processing unit 5 with the local oscillator output A mixer that generates an Intermediate Frequency (IF) signal. 9 is a band pass filter (BPF) which passes only frequencies of the 1.25 MHz band among the intermediate frequencies generated by the mixer 7, and 11 is an intermediate frequency passed by the band pass filter 9. PCS receive IF processing unit.

18 is an IMT-2000 transmitting IF processor for processing an IF signal to be transmitted to the base station for IMT-2000 service, and 16 is a band pass for passing only the 5 MHz band of the IF signal output from the IMT-2000 transmitting IF processor 18. A filter (BPF), 14 is a mixer for mixing the signal passed by the band pass filter 16 with a local oscillator output to generate an RF set in an IMT-2000 service, and 12 is a signal output from the mixer 14 Is an IMT-2000 RF processing unit for high frequency conversion and transmitting the same to the IMT-2000 mode duplexer 2.

19 is a PCS transmit IF processor for processing the IF signal to be transmitted to the base station for the PCS service, 17 is a band pass filter (BPF) that passes only the 1.25MHz band IF signal output from the PCS transmit IF processor 19; 15 is a mixer for generating RF set in the PCS service by mixing the signal passed by the band pass filter 17 with a local oscillator output, and 13 is a high frequency conversion of the signal output from the mixer 15 to the PCS mode. It is a PCS RF processing unit to transmit to the duplexer (3).

Since IMT-2000 service to be commercialized should support multimedia service in the future, signal bandwidth is different from PCS service currently in use. That is, the PCS RF signal band and the IMT-2000 RF signal band are different from each other, and the PCS IF signal band and the IMT-2000 IF signal band are different from each other. Therefore, the dual mode mobile terminal performing both the PCS operation mode and the IMT-2000 operation mode should have a PCS RF signal processor and an IMT-2000 RF signal processor, respectively, and a PCS IF signal processor and an IMT-2000 IF signal processor, respectively. Must be equipped. In this case, the signal band for the IMT-2000 service must be higher than the PCS signal band in order to minimize interference between the PCS service and the IMT-2000 service using the same free space as the physical transmission path and to support the multimedia. Therefore, PCS RF and IMT-2000 RF band cannot be shared. Therefore, since the PCS RF processing unit and the IMT-2000 RF processing unit cannot be shared and used, the dual mode mobile terminal is provided with the PCS RF processing unit and the IMT-2000 RF processing unit separately. In addition, the dual mode mobile terminal includes a PCS IF processing unit and an IMT-2000 IF processing unit to process both the PCS signal and the IMT-2000 signal.

In this general dual mode mobile terminal, not only the RF processing unit but also the IF processing unit are separately provided according to the PCS service and the IMT-2000 service to complicate the device configuration of the terminal, increase the device configuration cost, and inhibit the miniaturization. It became.

In addition, by passing only the IF of 5MHz bandwidth for the IMT-2000 IF, there was a disadvantage in that it cannot support signals of various bandwidths.

Accordingly, the present invention has been proposed to solve the above-mentioned conventional problems, and an object of the present invention is to share the PCS intermediate frequency and the IMT-2000 intermediate frequency so that one intermediate frequency processing apparatus is used as the PCS intermediate frequency and the IMT-2000. The present invention provides an intermediate frequency shared dual mode mobile terminal that can miniaturize the terminal and simplify the device configuration by processing all intermediate frequencies.

It is another object of the present invention to provide a switch between a mixer that generates an IF by mixing RF and a local oscillator output and a band pass filter that passes only a frequency of a set band, and is a switching operation by a bandwidth control signal. In the present invention, the intermediate frequency sharing dual mode mobile terminal has a variety of bandwidth selections of the IMT-2000 IF.

Intermediate frequency sharing dual mode mobile terminal according to the present invention to achieve the above object,

A first mixer generating an IMT-2000 IF to be shared with the IF in PCS mode by using the received IMT-2000 RF when operating in the IMT-2000 mode;

A second mixer for generating a PCS IF to share with the IMT-2000 IF using the received PCS RF when operating in the PCS mode;

Selectively switching the output of the first mixer to a first bandpass filter and a second bandpass filter according to a bandwidth control signal output from a modem of a dual mode mobile terminal and switching the output of the second mixer to a second bandpass filter A reception band selection switch for switching;

A first bandpass filter and a second bandpass filter selected by the reception band selection switch to respectively perform a band pass filtering of the reception IF;

An IF processor configured to process the IF output from the first bandpass filter and the second bandpass filter, and configures a receiver of a dual mode mobile terminal,

An IF processor which processes a PCS IF or an IMT-2000 IF;

A transmission band selection switch for switching the IF output from the IF processor according to a bandwidth control signal output from the modem to select a frequency bandwidth of the IF;

A third bandpass filter and a fourth bandpass filter selected by the transmission band selection switch and configured to receive a transmission IF from the IF processor and pass only a corresponding bandwidth, respectively;

The output of the third bandpass filter to the third mixer according to the mode control signal output from the modem of the dual mode mobile terminal so that the third bandpass filter and the fourth bandpass filter are shared between the third mixer and the fourth mixer. A mode selection switch for switching and selectively switching the output of said fourth bandpass filter to said third mixer and a fourth mixer;

A third mixer which mixes the IMT-2000 IF transmitted by the switching of the mode selection switch and the local oscillator output and transmits the RF signal to the IMT-2000 RF processor which performs RF conversion;

A fourth mixer for mixing the PCS IF transmitted by the switching of the mode selection switch and the local oscillator output and transmitting the result to the PCS RF processing unit performing RF conversion constitutes a transmitter of the dual mode mobile terminal. It is done.

The PCS IF has a 1.25MHz bandwidth, and the IMT-2000 IF has a 1.25MHz or 5MHz bandwidth.

1 is a block diagram of a conventional dual mode mobile terminal;

2 is a block diagram of an intermediate frequency sharing dual mode mobile terminal according to the present invention;

<Explanation of symbols for main parts of drawing>

30: switch 31: IMT-2000 mode duplexer

32: PCS mode duplexer 33: IMT-2000 RF processor

34: PCS RF processor 35, 36: first mixer, second mixer

37: Receive band selection switch 38: First band pass filter

39: second band pass filter 40: IF processor

41: IMT-2000 RF processor 42: PCS RF processor

43, 44: Mixer 3, Mixer 4 45: Mode selection switch

46: third bandpass filter 47: fourth bandpass filter

48: transmission band selector switch

Hereinafter, with reference to the accompanying drawings of the present invention, the intermediate frequency shared dual mode mobile terminal as described above in detail as follows.

In general, for the PCS service, the signal band is 1750-1780 MHz at the time of transmission, and the signal band is 1840-1870 MHz at the time of reception. In the case of the IMT-2000 service, the signal band is 1920-1980 MHz at the time of transmission, and the signal band is 2110-2170 MHz at the time of reception, which is different from the PCS. However, in the present invention, the intermediate frequency, which is an intermediate product of the process of converting a high frequency signal into a base band signal, is shared between the PCS and the IMT-2000. Therefore, IF frequency sharing allows PCS IF processor and IMT-2000 IF processor to be shared.

2 is a block diagram of an intermediate frequency sharing dual mode mobile terminal according to the present invention.

As shown, the dual mode mobile terminal according to the present invention is provided separately from the RF processing device of the PCS service and the RF processing device of the IMT-2000 service, like the conventional dual mode mobile terminal shown in FIG. However, the dual mode mobile terminal according to the present invention includes only one IF processor for the PCS service and one IF processor for the IMT-2000 service and share them with each other.

That is, the receiving IF processing apparatus of the dual mode mobile terminal is shared with the IF in the PCS mode by using the IMT-2000 RF output from the IMT-2000 RF processing unit 33 when operating in the IMT-2000 mode of the dual mode mobile terminal. A first mixer 35 for generating an IMT-2000 IF; A second mixer 36 for generating a PCS IF to share with the IMT-2000 IF using the received PCS RF when operating in the PCS mode; According to the bandwidth control signal output from the modem of the dual mode mobile terminal, the output of the first mixer 35 is selectively switched to the first bandpass filter 38 and the second bandpass filter 39 and the second mixer A reception band selection switch 37 for switching the output of the signal 36 to the second band pass filter 39; A first bandpass filter (38) and a second bandpass filter (39) selected by the reception band selection switch (37) to respectively perform band pass filtering of the reception IF; An IF processor 40 is configured to process the IF output from the first bandpass filter 38 and the second bandpass filter 39.

The first bandpass filter 38 passes a signal through the reception band selection switch 37 only 5 MHz bandwidth, and the second bandpass filter 39 receives a signal through the reception band selection switch 37. Only pass 1.25MHz bandwidth.

In addition, the transmitting side IF processing apparatus of the dual mode mobile terminal includes: an IF processing unit 49 for processing a PCS IF or an IMT-2000 IF; A transmission band selection switch 48 for switching the IF output from the IF processor 49 according to a bandwidth control signal output from the modem to select a frequency bandwidth of the IF; A third bandpass filter 46 and a fourth bandpass filter 47 which are selected by the transmission band selection switch 48 and receive the transmission IF from the IF processor 49 and pass only the corresponding bandwidths, respectively; According to the mode control signal output from the modem of the dual mode mobile terminal so that the third band pass filter 46 and the fourth band pass filter 47 are shared by the third mixer 43 and the fourth mixer 44. Switching the output of the third bandpass filter 46 to the third mixer 43 and selectively switching the output of the fourth bandpass filter 47 to the third mixer 43 and the fourth mixer 44. A mode selection switch 45; A third mixer (43) which mixes the IMT-2000 IF transmitted by the switching of the mode selection switch (45) and the local oscillator output and transmits it to the IMT-2000 RF processor (41) for performing RF conversion; The fourth mixer 44 mixes the PCS IF transmitted by the switching of the mode selection switch 45 and the local oscillator output, and transmits the RF signal to the PCS RF processor 42 that performs RF conversion.

The third bandpass filter 46 passes a signal through the transmission band selection switch 48 only 5 MHz bandwidth, and the fourth bandpass filter 47 receives a signal through the transmission band selection switch 48. Only pass 1.25MHz bandwidth.

Referring to the operation of the intermediate frequency shared dual mode mobile terminal according to the present invention as follows.

First, the operation of the receiving side device of the dual mode mobile terminal will be described. A signal received through the antenna of the terminal is input to the switch 30, and the switch 30 is received from the modem MODEM (not shown in FIG. 2). The received signal is switched in accordance with the output mode control signal. Thus, the PCS signal is transmitted to the PCS RF processor 34 through the PCS mode duplexer 32 by the PCS mode control signal, and the IMT-2000 signal is passed through the IMT-2000 duplexer 31 by the IMT-2000 mode control signal. It is transmitted to the IMT-2000 RF processor 33. After the RF processing is performed in each of the RF processing units 33 and 34, they are transmitted to the first and second mixers 35 and 36.

The conventional first mixer 35 generates an IF of the PCS service by mixing the signal output from the PCS RF processor 34 and the local oscillator output, and generates an IF having a 1.25 MHz bandwidth. The first mixer 35 generates a signal having a 1.25 MHz or 5 MHz bandwidth by using the signal output from the IMT-2000 RF processor 33 and outputs the signal to the reception band selection switch 37.

The reception band selection switch 37 switches the signal received by the bandwidth control signal output from the modem to the corresponding band pass filter. That is, when the operation mode of the dual mode mobile terminal is the PCS mode, the signal output from the second mixer 36 is transmitted to the second band pass filter 39 by the reception band selection switch 37. Thus, the PCS signal is filtered to the 1.25MHz bandwidth and transmitted to the IF processor 40.

In addition, when a 1.25 MHz bandwidth signal is generated in the first mixer 35 generating the IMT-2000 IF, the signal is switched to the second band pass filter 39 by the reception band selection switch 37 and the first mixer ( When the 5MHz bandwidth signal is generated at 35), it is switched to the first bandpass filter 38 by the reception band selection switch 37. In this way, a switch is provided between the mixer and the bandpass filter so that the IMT-2000 IF signal can be used not only with the conventional 5 MHz bandwidth but also with the 1.25 MHz bandwidth.

Next, the operation of the transmitting-side device of the dual-mode mobile terminal will be described. The IF signal to be transmitted from the terminal to the air passes through the IF processor 49 and then outputs to the transmission band selection switch 48. When the dual mode mobile terminal is operated in the PCS mode, the modem inside the terminal outputs the PCS mode control signal to the mode selection switch 45 and the switch 30, and also transmits a bandwidth control signal for passing a frequency of 1.25 MHz bandwidth. Output to the band select switch 48.

Thus, the IF output from the IF processor 49 is switched to the fourth band pass filter 47 by the transmission band selection switch 48 and filtered with a 1.25 MHz bandwidth. The mode selection switch 45 switches the output signal of the fourth band pass filter 47 to the fourth mixer 44 by the mode control signal. Thus, the signal through the fourth mixer 44 is converted into an RF signal in the 1750-1780 MHz band by the PCS RF processor 42 and then transmitted to the antenna through the PCS mode duplexer 32 and the switch 30.

On the other hand, when the dual mode mobile terminal is operated in the IMT-2000 mode, the modem inside the terminal outputs the IMT-2000 mode control signal to the mode selection switch 45 and the switch 30, and also the frequency of 1.25 MHz bandwidth or 5 MHz bandwidth. A bandwidth control signal for passing the signal is output to the transmission band selection switch 48. If the 1.25 MHz bandwidth control signal is output, the transmission band selection switch 48 switches the IMT-2000 IF signal output from the IF processor 49 to the fourth band pass filter 47 and outputs a 5 MHz bandwidth control signal. The transmission band select switch 48 switches the IMT-2000 IF signal output from the IF processor 49 to the third band pass filter 46.

The mode selection switch 45 outputs the output signal of the third bandpass filter 46 or the fourth bandpass filter 47 to the third mixer 43 by the IMT-2000 mode control signal. Accordingly, the signal through the third mixer 43 is converted into an RF signal in the 1920-1980 MHz band by the IMT-2000 RF processor 41 and then transmitted to the antenna through the IMT-2000 mode duplexer 31 and the switch 30. . In this way, the IMT-2000 IF is filtered through a 5 MHz bandwidth or a 1.25 MHz bandwidth, transmitted to an antenna, and then radiated.

As described above, the intermediate frequency shared dual mode mobile terminal according to the present invention, by sharing the IMT-2000 IF and PCS IF to share the PCS IF processing unit and the IMT-2000 IF processing unit, the dual mode mobile terminal Simplify the device configuration to reduce costs. In addition, it is possible to miniaturize the terminal by simplifying the device configuration.

A mixer between the RF and local oscillator outputs to generate an IF and a switch between multiple band pass filters and a 1.25 MHz band pass filter and a 5 MHz band pass filter can be selectively used for switching operation by a bandwidth control signal. The bandwidth selection of the IMT-2000 IF will be diversified.

Claims (2)

A dual mode mobile terminal selectively performing an operation mode for a Personal Communication Services (PCS) service and an operation mode for an International Mobile Telecommunications (IMT-2000) service. The receiving unit of the dual mode mobile terminal, A first mixer for generating an IMT-2000 IF to be shared with an intermediate frequency (IF) in the PCS mode by using a received IMT-2000 Radio Frequency (RF) signal when operating in the IMT-2000 mode. Wow; A second mixer for generating a PCS IF to share with the IMT-2000 IF using the received PCS RF when operating in the PCS mode; Selectively switching the output of the first mixer to a first bandpass filter and a second bandpass filter according to a bandwidth control signal output from a modem of a dual mode mobile terminal and switching the output of the second mixer to a second bandpass filter A reception band selection switch for switching; A first bandpass filter and a second bandpass filter selected by the reception band selection switch to respectively perform a band pass filtering of the reception IF; An IF processor configured to process the IF output from the first bandpass filter and the second bandpass filter, The transmitting unit of the dual mode mobile terminal, An IF processor which processes a PCS IF or an IMT-2000 IF; A transmission band selection switch for switching the IF output from the IF processor according to a bandwidth control signal output from the modem to select a frequency bandwidth of the IF; A third bandpass filter and a fourth bandpass filter selected by the transmission band selection switch and configured to receive a transmission IF from the IF processor and pass only a corresponding bandwidth, respectively; The output of the third bandpass filter to the third mixer according to the mode control signal output from the modem of the dual mode mobile terminal so that the third bandpass filter and the fourth bandpass filter are shared between the third mixer and the fourth mixer. A mode selection switch for switching and selectively switching the output of said fourth bandpass filter to said third mixer and a fourth mixer; A third mixer which mixes the IMT-2000 IF transmitted by the switching of the mode selection switch and the local oscillator output and transmits the RF signal to the IMT-2000 RF processor which performs RF conversion; And a fourth mixer configured to mix the PCS IF transmitted by the switching of the mode selection switch and the local oscillator output and transmit the RF signal to a PCS RF processor which performs RF conversion. The method of claim 1, The PCS IF has a 1.25 MHz bandwidth, The IMT-2000 IF has a 1.25MHz or 5MHz bandwidth, dual-frequency shared dual mode mobile terminal.