JP2001177431A - Two-way communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize a two-way communication device. SOLUTION: This device realizes the miniaturized two-way communication device that employs a PLL synthesizer section 52 that is used in common for a transmission section 50 including a modulation circuit 10 and for a reception section 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-way communication device used in the field of information communication using specified low power.

[0002]

2. Description of the Related Art A conventional two-way communication device will be described below.

FIG. 4 is a block diagram of a conventional two-way communication device. As shown in FIG. 4, a conventional two-way communication device includes a substrate housed in a substantially rectangular housing, an antenna terminal 20 provided on the substrate, and an antenna switch 21 connected to the antenna terminal 20. And a transmitting unit connected to one terminal of the antenna switch 21 and a receiving unit connected to the other terminal of the antenna switch 21. The transmitting unit includes an input terminal 30 to which a baseband signal is input. The input terminal 30 is connected to the modulation circuit 29, and the output of the modulation circuit 29 is input to the voltage controlled oscillator 25. One output of the voltage-controlled oscillator 25 and the output of the crystal reference oscillator 28 are input to the PLLIC 27, and their phases are compared. The output is connected to the input of the voltage-controlled oscillator 25 via the low-pass filter 26. Here, the voltage controlled oscillator 25 and the low-pass filter 26
The first PL by the PLLIC 27 and the crystal reference oscillator 28
An L synthesizer section is formed.

The other output of the voltage controlled oscillator 25 is
The output of the first PLL synthesizer is connected to the first transmitting amplifier 24, and this output is connected to the second transmitting amplifier 23.
The output is connected to the input terminal of the transmission RF filter 22, and the output of the transmission RF filter 22 is connected to one terminal of the antenna switch 21.

[0005] Further, the receiving unit is an antenna switch 21.
The signal output from the other terminal of the first RF filter 33 is connected to the first RF filter 33 for reception.
Is connected to a receiving amplifier 34, a second receiving RF filter 35 is connected to the output of the receiving amplifier 34, and an output of the second receiving RF filter 35 is connected to one input and the other A first mixer for reception 36 connected to the output of the voltage-controlled oscillator 31 at the input of
The receiving I to which the output of the first receiving mixer 36 is connected
The F filter 37 and the output of the receiving IF filter 37 are connected to one input and the other input is the first input.
A second mixer for reception 38 in which the output of the crystal reference oscillator 28 commonly used in the PLL synthesizer unit and the second PLL synthesizer unit is connected to the other input;
The demodulator 39 was connected to the output of the mixer 38, and the output terminal 40 of the receiver was connected to the output of the demodulator 39.

Here, the voltage controlled oscillator 31, the low-pass filter 32, the PLLIC 27, and the crystal reference oscillator 2
8 together form a second PLL synthesizer section. The PLLIC 27 and the crystal reference oscillator 28 are shared with the second PLL synthesizer. Thus, the first PLL synthesizer unit connected to the transmitting unit and the second PLL synthesizer unit connected to the receiving unit are independent P
An LL synthesizer section was provided.

[0007]

However, in such a conventional circuit configuration, since the voltage-controlled oscillator can change only about 3 MHz per 1 V, two sets of the same PLL synthesizer are required, and miniaturization is difficult. there were.

The present invention has been made to solve such a problem, and has as its object to provide a miniaturized two-way communication device.

[0009]

In order to achieve this object, a two-way communication apparatus according to the present invention is such that a PLL synthesizer unit is shared by a transmitting unit and a receiving unit. Thereby, size reduction can be achieved.

[0010]

The invention according to claim 1 is provided on a substrate housed in a substantially rectangular metal housing, and includes an antenna terminal provided on the substrate, and an antenna terminal provided on the substrate. An antenna switch connected to a terminal, a transmitting unit connected to one terminal of the antenna switch, and a receiving unit connected to the other terminal of the antenna switch, wherein the transmitting unit has a baseband signal. An input terminal to be input, a modulation circuit connected to the input terminal, a PLL synthesizer connected to an output of the modulation circuit, and a first transmission amplifier connected to one output of the PLL synthesizer. A second transmitting amplifier connected to the output of the first transmitting amplifier, and a transmitting RF connected between the output of the second transmitting amplifier and one terminal of the antenna switch. A receiving filter connected to the other terminal of the antenna switch, a receiving amplifier to which an output of the receiving first RF filter is connected, and a receiving amplifier. A second receiving RF filter having an output connected thereto, and a first receiving RF filter having the output of the second receiving RF filter connected to one input and the other input of the PLL synthesizer section connected to the other input. A mixer, a reception IF filter to which the output of the first reception mixer is connected,
A second mixer for reception having an output of the reception IF filter connected to one input and an output of the crystal reference oscillator of the PLL synthesizer section connected to the other input; and a second mixer for reception. And the output terminal of the receiver to which the output of this demodulator is connected. Since the PLL synthesizer unit is shared by the transmission unit and the reception unit, the mounting area is And the size can be reduced. Further, cost reduction can be achieved.

The voltage controlled oscillator forming the PLL synthesizer section according to the second aspect of the present invention is the two-way communication apparatus according to the first aspect, which is capable of varying about 32 MHz per volt, and has a transmission radio frequency and a reception frequency. Even if the local oscillation frequencies are separated by the IF frequency, they can be shared because the variable range is wide, and the adjustment of the resonance circuit can be eliminated.

The invention according to claim 3 is the bidirectional communication device according to claim 2, wherein the transmitting RF filter and the receiving first RF filter are separated by a first partition plate with an antenna switch interposed therebetween. Since the antenna switch is interposed between the transmission unit and the reception unit, the transmission unit and the reception unit are separated from each other, and the transmission output does not go around the reception unit. In addition, the structure is such that radiation noise from the inside is hardly radiated to the outside of the antenna.

According to a fourth aspect of the present invention, a four-layer substrate is used as the substrate, and the first layer has a transmitting RF filter and a receiving first R filter formed of microstrip lines.
3. The bidirectional communication device according to claim 2, wherein an F filter and a second RF filter for reception are provided, and an inner layer of the substrate corresponding to these filters is not formed with a ground. Is low loss, and high performance RF filter characteristics can be realized. In other circuit parts, it is hardly affected by the parasitic capacitance between layers.
It has the characteristic that there is little variation.

According to a fifth aspect of the present invention, the transmission second amplifier is disposed on the back surface of the substrate, the transmission first amplifier is disposed on the front surface, and the transmission RF filter and the reception first R are arranged.
The F filter, the first amplifier for transmission and the first mixer for reception are separated by a second partition plate, and the first amplifier for transmission and the first mixer for reception and the PLL synthesizer section are connected to a third partition plate. The two-way communication device according to claim 2, which has a function of preventing radiation from the PLL synthesizer unit to the first transmitting amplifier and radiation to the second receiving RF filter.

According to a sixth aspect of the present invention, the resonance circuit of the voltage controlled oscillator is arranged near one side of the housing, and the receiving IF filter is arranged near the other side of the housing. By arranging it near the side surface of the housing, it is possible to take a strong ground by utilizing the low impedance of the housing. By arranging the filter on the housing on the opposite side of the resonance circuit, a spatial distance is increased, so that the resonance circuit does not adversely affect the IF filter.

According to a seventh aspect of the present invention, the resonance circuit of the voltage controlled oscillator includes a capacitor having one connected to a base of an oscillation amplifier, the other of which is connected to an inductor and a capacitor, and the other of which is connected to an inductor and a capacitor. 3. The capacitor according to claim 2, wherein the capacitor is connected to a ground, the other of the capacitors is connected to a modulation circuit, the ground connected to the inductor is conducted through a via to a beta land of an inner layer of the substrate, and soldered to a housing near the via. The two-way communication device described above, which can take a reliable ground, promotes stable oscillation excellent in external noise resistance, and has a high resonance Q and C / N because it is a resonance circuit including only an inductor. improves.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a two-way communication device according to an embodiment of the present invention. FIG. 2A is a layout view as viewed from the front, and FIG. FIG. 3C is a layout view as viewed from the back.

The two-way communication device according to the present embodiment
An antenna terminal 1 provided on the substrate, an antenna switch 2 connected to the antenna terminal 1, a transmitting unit 50 connected to one terminal of the antenna switch 2, and connected to the other terminal of the antenna switch 2 Receiving unit 51
It is composed of

The transmitting section 50 has an input terminal 11 to which a baseband signal is input, and the input terminal 11 is connected to the modulation circuit 10, and the output of the modulation circuit 10 is input to one of the voltage controlled oscillators 6. A low-pass filter 7 is connected to the other input of the voltage-controlled oscillator 6.
One input of the PLLIC 8 is connected to the other output of the voltage controlled oscillator 6, and the other input of the PLLIC 8 is connected to the output of the crystal reference oscillator 9. The output of the PLLIC 8 is connected to the low-pass filter 7 to form a PLL synthesizer section 52.

The other output of the voltage controlled oscillator 6 is PL
The signal is distributed as an output of the L synthesizer unit 52, one of which is connected to the input of the first transmitting amplifier 5, the output of the first transmitting amplifier 5 is connected to the input of the second transmitting amplifier 4, and The output of the second amplifier 4 is connected to the input of the transmission RF filter 3, and the output of the transmission RF filter 3 is connected to one terminal of the antenna switch 2.

The receiving section 51 converts the signal output from the other terminal of the antenna switch 2 into the first RF filter 12 for reception.
The output of the first receiving RF filter 12 is connected to a receiving amplifier 13, the second receiving RF filter 14 is connected to the output of the receiving amplifier 13, and the output of the second receiving RF filter 14 is First mixer 1 for reception
5, and the other input is connected to the other output of the PLL synthesizer unit 52. Further, a receiving IF filter 16 connected to the output of the first receiving mixer 15 and an output of the receiving IF filter 16 connected to one input and a crystal of the PLL synthesizer unit 52 connected to the other input. The second receiving mixer 17 to which the output of the reference oscillator 9 is connected, the demodulator 18 to which the output of the second receiving mixer 17 is connected, and the receiver to which the output of the demodulator 18 is connected An output terminal 19 is provided.

The oscillation frequency of the voltage controlled oscillator 6 forming the PLL synthesizer section 52 is in the 430 MHz band, and its frequency sensitivity is widened to approximately 32 MHz per 1 V. Therefore, the oscillation frequency can be largely controlled by the control voltage applied to the voltage-controlled oscillator 6, so that the transmitting unit 50 and the receiving unit 51 can be used in common.

As shown in FIG. 3, the resonance circuit 60 constituting the voltage controlled oscillator 6 is a T-type resonance circuit formed between the modulation circuit 10 and the transistor 61. , And an inductor 64 connected between the connection point of the series connection and the ground. And this inductor 64
Is connected to a beta land formed on an inner layer of the substrate via a via (through hole for connecting the inside of the substrate), and a metal housing (hereinafter referred to as a frame) 49 shown in FIG. It is connected. Therefore, stable oscillation becomes possible.

Next, the arrangement will be described with reference to FIG. As shown in FIG. 2A, in the PLL synthesizer section 52, the resonance circuit 41 is arranged on the side surface of the frame 49, and on the back surface, as shown in FIG. The voltage controlled oscillator 6 is shown in FIG.
By connecting the back surface soldering portion 44, the soldering portion 45, and the soldering portion 46 to the third partition plate 48 and bringing the ground close thereto, excellent external noise resistance characteristics can be obtained and stable oscillation can be promoted. . First RF filter for reception 12
Is separated by the second partition plate 47 and the second RF for reception
The filter 14 and the first receiving mixer 15 are separated from the PLL synthesizer section 52 by a third partition plate 48.

The PLL synthesizer 52 and the first transmission
Separation between the amplifier 5 and the second receiving RF filter 14;
RF filter 3 for transmission and first RF filter 12 for reception
In this structure, the coupling between the input and the output can be eliminated by the first partition plate 54, and excellent characteristics can be obtained. The receiving IF filter 16 can easily reproduce its original performance by connecting the ground terminal closer to the frame 49 and the soldering portion 42.

Further, as shown in FIG.
A four-layer substrate composed of 6, 57, 58, and 59 is provided, and the vicinity 55 of the filter is a portion where no ground is formed. This increases the Q of the inductance. Further, by using a PLL synthesizer unit 52 that can be used in common by the transmission unit 50 and the reception unit 51, miniaturization and cost reduction are achieved. Also, the circuit configuration is in the specific low power field, and the transmitting unit 50 uses the direct modulation method by the modulation circuit 10, and the receiving unit 51 uses the double super heterodyne by the first receiving mixer 15 and the second receiving mixer 17. Method is used.

[0027]

As described above, according to the present invention, the two-way communication device of the present invention can reduce the cost and the mounting area by sharing a set of synthesizers for the transmitter and the receiver. , Miniaturization can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a two-way communication device according to an embodiment of the present invention.

2A is a layout view of the front surface of the board of the two-way communication device, FIG. 2B is a cross-sectional view of the board, and FIG.

FIG. 3 is a wiring diagram of a resonance circuit forming the voltage-controlled oscillator.

FIG. 4 is a block diagram of a conventional two-way communication device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna terminal 2 antenna switch 3 transmission RF filter 4 transmission second amplifier 5 transmission first amplifier 6 voltage controlled oscillator 7 low-pass filter 8 PLLIC 9 crystal reference oscillator 10 modulation circuit 11 input terminal 12 reception first RF filter 13 reception Amplifier for reception 14 second RF filter for reception 15 first mixer for reception 16 IF filter for reception 17 second mixer for reception 18 demodulator 19 output terminal 50 transmission unit 51 reception unit 52 PLL synthesizer unit

Claims (7)

[Claims] An antenna terminal provided on a substrate housed in a substantially rectangular metal housing, an antenna terminal provided on the substrate, an antenna switch connected to the antenna terminal, and an antenna A transmitting unit connected to one terminal of the switch, and a receiving unit connected to the other terminal of the antenna switch, the transmitting unit has an input terminal to which a baseband signal is input, and an input terminal Connected modulation circuit, and P connected to the output of the modulation circuit.
An LL synthesizer unit, a first transmission amplifier to which one output of the PLL synthesizer unit is connected, a second transmission amplifier to which the output of the first transmission amplifier is connected, and a second amplifier for transmission An output and an RF switch for transmission connected between one terminal of the antenna switch, and the receiving unit includes a first RF filter for reception connected to the other terminal of the antenna switch; A receiving amplifier to which the output of the first RF filter is connected, and a second R receiving amplifier to which the output of the receiving amplifier is connected
F filter and the output of the second RF filter for reception are connected to one input and the other input is the PL
The first receiving receiver to which the other output of the L synthesizer is connected
A mixer, an IF filter for reception to which the output of the first mixer for reception is connected, and an output of the IF filter for reception connected to one input and the P input to the other input.
The second mixer for reception to which the output of the crystal reference oscillator of the LL synthesizer unit is connected, the demodulator to which the output of the second mixer for reception is connected, and the receiver to which the output of this demodulator is connected A bidirectional communication device comprising an output terminal. 2. The two-way communication apparatus according to claim 1, wherein the voltage controlled oscillator forming the PLL synthesizer section is capable of varying approximately 32 MHz per 1 V in a 430 MHz band. 3. The two-way communication device according to claim 2, wherein the transmitting RF filter and the receiving first RF filter are separated by a first partition plate with an antenna switch interposed therebetween. 4. A four-layer substrate is used as the substrate and the first
On the layer, a transmitting RF filter, a first receiving RF filter, and a second receiving RF filter constituted by microstrip lines are provided.
3. The two-way communication device according to claim 2, wherein RF filters are provided, and an inner layer of the substrate corresponding to these filters has no ground. 5. A transmission second amplifier is disposed on the back surface of the substrate, and a transmission first amplifier is disposed on the front surface. The transmission RF filter and the reception first RF filter, the transmission first amplifier and the reception 3. The bidirectional device according to claim 2, wherein the first mixer is separated by a second partition plate, and the first amplifier for transmission and the first mixer for reception and the PLL synthesizer unit are separated by a third partition plate. 4. Communication device. 6. The two-way communication device according to claim 2, wherein a resonance circuit of the voltage controlled oscillator is arranged near one side of the housing, and a receiving IF filter is arranged near the other side of the housing. . 7. A resonance circuit of a voltage controlled oscillator, comprising: a capacitor having one connected to a base of an oscillation amplifier; the other of the capacitor being connected to an inductor and a capacitor; the other of the inductor being connected to ground; 3. The two-way communication according to claim 2, wherein the other of the capacitors is connected to a modulation circuit, a ground connected to the inductor is conducted through a via to a beta land in an inner layer of the substrate, and soldered to a housing near the via. apparatus.