JPH10107676A - Communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correspond to a dual band in which the frequency intervals between a transmitting band and a receiving band are different from each other and also to make this device small, light, inexpensive and also be low power consumption by setting the frequency of a voltage-controlled offset signal oscillator (offset VCO) so that it may be equal to the difference of intervals between transmitting band and receiving band. SOLUTION: This device appropriately combines an offset VCO-A2, a high frequency VCO-A3 and a high frequency VCO-B4 and generates a high frequency that is needed for transmission and receiving. The difference of the two transmitting band and receiving band is set to be equal. Thereby, a high frequency signal that is needed for the transmission and receiving of the dual band can be created with the minimum block structure. In addition, the frequency of an IF signal becomes equal in either case of two receiving bands, the structure of a receiving system after a receiving mixer 30 can be simplified, and it is possible to make this device light and be low power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus which supports a so-called dual band in which a transmission band and a reception band have different frequency intervals.

More specifically, the present invention comprises a first band including a pair of transmission band A (frequency range: f _{A1 to} f _A2 ) and reception band A ′ (frequency range: f _{A′1 to} f _A′2 ). And a pair of transmission bands B (frequency range f _B1 to
_fB2 ) and the reception band B '(frequency range: _{fB'1 to} fB'1).
_{B ′ 2} ) and a communication device having a second communication band including | f _Ai −f _A′i | | f _Bi −f _B′i |, i = 1 or 2.

[0003]

2. Description of the Related Art There are various systems for radio communication using radio waves, such as analog systems and digital systems.
Each system is assigned a frequency band centering on the UHF band. However, the number of subscribers of digital mobile phones and the like has increased remarkably in recent years, and communication traffic has become extremely congested, so that a situation has arisen where subscribers cannot freely access a communication network.

As one method for avoiding this problem, when the communication traffic of a certain wireless communication system is extremely congested, some users of the communication system have relatively free communication traffic. Methods have been proposed for getting into frequency bands of other wireless communication systems.

[0005]

However, two different wireless communication systems usually use different frequency bands and also have different frequency intervals between the transmission band and the reception band. It is.

[0006] Therefore, in order to realize the above proposal, a communication device that can be used in both of the two wireless communication systems must integrate two communication devices corresponding to the two wireless communication systems. The communication device becomes large in configuration.

[0007] However, in general, there is a strong demand for miniaturization, weight reduction, and cost reduction of a portable communication device, and there is a problem in the above-described configuration.

A communication device using radio waves needs a signal for frequency conversion at the time of transmission or reception.
To generate this signal, a frequency oscillator is used, but if the transmission frequency and the oscillation frequency are the same, leakage from the oscillator causes a problem during transmission. Therefore, the transmission frequency is synthesized by synthesizing the frequencies using two different oscillators. On the other hand, at the time of reception, the signal is converted into a lower frequency in several stages, but at the first frequency conversion, a part of the oscillator used at the time of transmission is often used.

As described above, when the communication traffic of a certain wireless communication system becomes extremely congested, a part of the users of the communication system is transferred to another wireless communication system where the communication traffic is relatively free. Even in a case where two radio systems communicate in different frequency bands, the two different radio communication systems usually use different frequency bands and also have different frequency intervals between the transmission band and the reception band. In order to realize the above-mentioned entry, a communication device (specifically, a dual-band transceiver) that can be used in both of the two wireless communication systems is required.

In order to configure such a dual-band transceiver, it is possible to first configure two independent transceivers suitable for the respective radio communication systems and integrate the respective transceivers. -It is not preferable as a portable transceiver that strongly demands reduction in weight and power consumption.

SUMMARY OF THE INVENTION An object of the present invention is to provide a communication device (for example, a transceiver of the FDD / TDMA communication system) corresponding to a dual band in which the frequency interval between the transmission band and the reception band is different from each other, and which is small and lightweight. Another object of the present invention is to provide a communication device capable of reducing power consumption.

[0012]

The present inventors have proposed, for example, F
A dual-band communication device such as a DD / TDMA communication system includes two voltage-controlled high-frequency signal oscillators (high-frequency VCO), one voltage-controlled offset signal oscillator (offset VCO), a mixer, and a high-frequency signal for reception. A changeover switch, by setting the frequency of the offset VCO to be equal to n times the difference between the intervals of the two transmission bands and the reception band, or by setting two high-frequency VCOs and two offset VCOs; +90
A phase shifter, a single sideband mixer having a -90 ° phase shifter, and at least a switch for switching the phase shifter are arranged, and the frequencies of the two high-frequency VCOs and the two offset VCOs are set to appropriate frequencies. As a result, it has been found that a compact, lightweight, low-cost communication device can be realized, and the present invention has been accomplished.

That is, according to the present invention, a pair of transmission bands A
(Frequency Range: f _A1 ~f _A2) and the reception band A '(frequency range: f _A'1 ~f _A'2) a first communication band including a pair of transmission band B (the frequency range f _B1 ~f _B2) and receive band B '(frequency range: f _B'1 ~f _B'2) communication device having a second communication band including (but, | f _Ai
−f _A′i | ≠ | f _Bi −f _B′i |, i = 1 or 2), wherein the first variable frequency oscillator having the first oscillation frequency range and the second oscillation frequency range are And a second variable frequency oscillator having an offset frequency f _OS (f _OS = | (f _Ai) equal to the difference between the intervals of the two transmit and receive bands.
−f _A′i ) | − | f _Bi −f _B′i |) |), one of the first variable frequency oscillator and the second variable frequency oscillator, and the offset A mixer circuit for inputting signals respectively output from oscillators, and a switch for extracting an output signal of the mixer circuit or an output signal of the first variable frequency oscillator or the second variable frequency oscillator as a local oscillation signal And a circuit. In addition, it is preferable to include a receiving mixer circuit that inputs the received high-frequency signal and the signal output from the switch circuit and outputs an IF signal. Further, it is preferable to use a voltage controlled oscillator (VCO) as the first variable frequency oscillator, the second variable frequency oscillator, and the offset oscillator. Using these communication devices, FDD
It is possible to execute communication by (frequency division duplex) or TDMA (time division multiple access) communication method. Further, the oscillation frequency f _OS of the offset oscillator is
It is set equal to n times (the natural number of n ≧ 2) the difference between the intervals between the two transmission bands and the reception band (f _OS = n | (| f
_{Ai -f A'i | - | f Bi} -f B'i |) |), it is also possible to employ a configuration to be input to the mixer circuit via the n frequency divider circuit is provided separately. Further, a single sideband mixer can be used as the mixer circuit.

[0014] More specifically, the transmission band A is 94
0 to 960 MHz, the transmission band B is 915 to 940
MHz, the reception band A 'is 810-830 MHz,
The reception band B 'is 860-885 MHz, and any of the variable frequency oscillators is 990-1035 MHz.
z, wherein the frequency f _{OS of the} offset oscillator is m times 75 MHz (m is a natural number),
A communication device having an m frequency dividing circuit can be realized only when m ≧ 2.

In another aspect of the present invention, a pair of transmission bands A
(Frequency Range: f _A1 ~f _A2) and the reception band A '(frequency range: f _A'1 ~f _A'2) a first communication band including a pair of transmission band B (the frequency range f _B1 ~f _B2) and receive band B '(frequency range: f _B'1 ~f _B'2) communication device having a second communication band including (but, | f _Ai
−f _A′i | ≠ | f _Bi −f _B′i |, i = 1 or 2), wherein the first and second variable frequency oscillators, the first and second offset oscillators, and + 90 ° A single sideband mixer circuit having a phase shifter and a −90 ° phase shifter; and a changeover switch for selecting one of the phase shifters, wherein the frequency (f _VCOA ) of the first offset oscillator and the second The difference between the frequency (f _VCOB ) of the offset oscillator becomes equal to the difference between the intervals between the two transmission bands and the reception band (| f _VCOA −f _VCOB | = |
(| F _Ai −f _A′i | − | f _Bi −f _B′i |) |). Here, the frequency (f _VCOA ) of the first offset oscillator and the frequency (f _VCOA ) of the second offset oscillator
_VCOB ) is set equal to n times (n is a natural number, n ≧ 2) the difference between the intervals between the two transmission bands and the reception band (| f _VCOA −f _VCOB | = n | (| f _Ai − f _A'i |-| f
_Bi− f _B′i |) |), and a configuration in which the signal is input to the single sideband mixer circuit via a separately provided _{frequency-dividing} circuit. Further, it is preferable to use a voltage controlled oscillator (VCO) as the first and second variable frequency oscillators and the first and second offset oscillators. Using these communication devices, FDD
It is possible to execute communication by (frequency division duplex) or TDMA (time division multiple access) communication method.

All of the above communication devices are preferably used, for example, as transceiver devices.

The functions of the first and second variable frequency oscillators can be provided in a single variable frequency oscillator.

Further, the present inventors have disclosed a dual-band transceiver, in which two frequency amplifiers, a single sideband mixer and a double sideband mixer for inputting signals from those frequency amplifiers, and switching between these two mixers are provided. At least place the switch
It has been found that a compact, lightweight and low-power-consumption transceiver can be realized by synthesizing appropriate frequencies using these mixers, and the present invention has been made based on this fact.

More specifically, when manufacturing a transceiver of the FDD / TDMA communication system corresponding to the dual band, a high frequency signal required for transmission is:
Both signals from the high-frequency VCO and the offset VCO are mixed and generated by a single sideband mixer, while high-frequency signals required for reception are mixed by a double-sideband mixer to mix both signals from the high-frequency VCO and the offset VCO. The generation and the selection of each of these generated signals as needed are the basis for recalling the present invention.

That is, according to the present invention, in a communication apparatus corresponding to a dual band in which a transmission band and a reception band have different frequency intervals, a frequency synthesizer included in the communication apparatus includes a single sideband signal and / or a double sideband signal. It is provided with a mixer circuit for outputting a signal.

Here, the mixer circuit includes a single sideband mixer and a double sideband mixer,
A configuration including a switch circuit for selectively extracting the output signal of the single sideband mixer or the output of the double sideband mixer can be adopted.

Further, the single side band mixer is constituted by two double side band mixers having an output section coupled thereto, and by stopping one of the functions of the two double side band mixers, the single side band mixer is formed as a double side band mixer. It can be used.

Moreover, since the frequency of the transmission high-frequency signal generated by the present invention is shifted from the frequency of the high-frequency VCO by the offset signal frequency, the frequency of the high-frequency VCO becomes unstable due to the transmission high-frequency signal. No problem. Therefore, the transmission high-frequency signal generated by the present invention is suitable for driving a direct modulation type quadrature modulator or the like.

The high-frequency signal for reception generated according to the present invention is used for mixing and down-converting a received signal in a reception band by a reception mixer to generate an IF signal. The IF frequency can be constant regardless of the reception band.

Further, according to the present invention, at the time of reception, the frequency is synthesized by the double sideband mixer, so that the power consumption can be reduced. In addition, since the transmission and reception frequencies are combined by a single sideband mixer or a double sideband mixer, it is very effective to realize a small, lightweight, and low-cost dual-band communication device.

That is, according to the present invention, a high-frequency signal suitable for dual-band transmission and reception can be generated with a minimum block configuration, and at the same time, dual-band compatible communication that is small, lightweight, and has low power consumption. The device can be realized.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a circuit diagram showing a first embodiment. In this figure, 1 is a mixer, 2 is a voltage-controlled oscillator (hereinafter referred to as an offset VCO) for generating a signal of an offset frequency described later.
-A), 3 is a high frequency VCO having a first oscillation frequency range (hereinafter, VCO-A), 4 is a high frequency VCO having a second oscillation frequency range (hereinafter, VCO-B), 5 and 6 Is a high-frequency signal (local oscillation signal) switch for reception, 20 is a transmission processing circuit, 23 is an input switch of VCO-A3, 24 is an input switch of VCO-B4, 28 is a reception processing circuit, and 30 is a reception mixer. is there.

In the first embodiment shown in FIG. 1, an offset VCO-A2, a high frequency VCO-A3, and a high frequency VCO-B4 are appropriately combined to generate a high frequency required for transmission and reception. These oscillators may use a VCO module, or may include transistors, varicaps, tank circuits, and the like. It is also possible to combine with a PLL circuit to select a channel frequency.

The mixer 1 may be a double sideband mixer or a single sideband mixer configured in combination with a phase shifter. It is also possible to adopt a configuration in which the filter is combined with a filter for removing unnecessary waves.

The receiving high-frequency signal changeover switches 5 and 6 are connected to the high-frequency VCO-A3 or the high-frequency VCO-B4
Or a high-frequency signal generated by mixing the signal from the offset VCO-A2 with the mixer 1 or a direct high-frequency VCO-A
3 or a high-frequency signal from the high-frequency VCO-B4, and its configuration is not particularly limited.

The switching of the high-frequency signal for reception is performed according to whether the reception band is A 'or B', and whether the communication apparatus is in an operation mode of transmission, reception or standby. The switching signal is usually supplied from a microcomputer or the like that manages the communication system of the communication device, but this is not particularly limited.
Further, in order to reduce current consumption, a function of turning off a power supply of a high-frequency VCO, a mixer, or the like can be incorporated in accordance with the timing of a switching signal.

Hereinafter, the first embodiment of the present invention will be described specifically.

The transmission band A and the reception band A 'have frequency ranges of 940 to 960 MHz and 810 to 830 MHz.
z, the other transmission band B and reception band B '
The dual-band transceivers of 940 MHz and 860-885 MHz were configured as shown in FIG.

The actual transceiver device has the configuration shown in FIG.
, An LNA, an RF filter, and the like are required as the reception processing circuit 28, and a quadrature modulator, a power amplifier, and the like are required as the transmission processing circuit 20.

The setting of the frequency of the offset VCO-A2, which is a feature of this embodiment, will be described below.

In the case of the present embodiment, the difference between the two transmission bands and the reception band is 130 MHz (= | f _Ai -f _A'i
|), 55 MHz (= | f _Bi −f _B'i |),
The frequency of the offset VCO-A2 is set to 75 MHz (= |
(| F _Ai −f _A′i |) − | f _Bi −f _B′i |) |).

As the mixer 1, a low sideband single sideband mixer was used. The high frequency VCO includes a high frequency VCO-A3 having a frequency range of 1015 to 1035 MHz and a high frequency VCO-B having a frequency range of 990 to 1015 MHz.
Two of four were used. The high frequency signal changeover switch for reception is configured by combining a simple on / off type switch 6 and a switch 5.

In the dual-band transceiver constructed as shown in FIG. 1, the operation when the transmission band and the reception band are A and A 'is as follows.

At the time of transmission, the high frequency VCO-A3 (101
5-1035 MHz) and the offset VCO-A2 (75
MHz) in the low-sideband single-sideband mixer 1 to mix high-frequency signals (940 to 960) required for transmission.
MHz). Also, at the time of reception, the high-frequency VCO-A
3 (1015 to 1035 MHz) and offset VCO-
The A2 (75 MHz) signal is mixed by the low sideband single sideband mixer 1 and the switch 6 of the high-frequency signal changeover switch for reception is turned on and the switch 5 is turned off, so that the high-frequency signal necessary for reception ( 940-96
0 MHz). In this case, the received signals (810 to 83
0 MHz) is a high frequency signal for reception (940 to 960 MH)
z) and the IF signal (130
MHz), and necessary demodulation processing is performed thereafter.

On the other hand, the transmission band and the reception band are B and B '
The operation when is is as follows.

At the time of transmission, the high frequency VCO-B4 (990
1015 MHz) and offset VCO-A2 (75M
Hz) signal into a low sideband single sideband mixer 1
High-frequency signal (915-940M)
Hz). At the time of reception, the high-frequency VCO-B4 (990 to 101) is turned on by turning on the switch 5 and turning off the switch 6 of the receiving high-frequency signal changeover switch.
5 MHz) and the high-frequency signal (99
0 to 1015 MHz). In this case, the received signal (8
60 to 885 MHz) is a receiving high-frequency signal (990 to 885 MHz).
1015 MHz) and the IF mixed by the reception mixer 30
Signal (130 MHz), and thereafter, necessary demodulation processing is performed.

According to the first embodiment, a high-frequency signal required for dual-band transmission and reception can be generated with a minimum block configuration.
130 MHZ for both reception bands A 'and B'
z, and the configuration of the receiving system after the receiving mixer 30 can be simplified.

In the first embodiment, the high-frequency VC
As O, two of the frequency range of 1015 to 1035 MHz and 990 to 1015 MHz were used,
It goes without saying that only one high-frequency VCO having a frequency range of 990 to 1035 MHz or more may be used. Also, the high frequency VCO-A3 and the high frequency VCO-B
For the switching of No. 4, a changeover switch may be provided, or it may be simply turned on and off.

Embodiment 2 FIG. 2 shows Embodiment 2 of the present invention. In this figure,
7 is a second offset oscillator (hereinafter referred to as VCO-B7) 8 and 9 are + 90 ° and −90 ° phase shifters, respectively, and 12 is a single sideband mixer.

In FIG. 2, high-frequency VCO-A3, high-frequency VCO-B4, offset VCO-A2 and offset VCO-B7 are appropriately combined with each other,
Generates high frequency frequencies required for transmission and reception.

The above oscillator may use a VCO module, or may be composed of a transistor, a varicap, a tank circuit and the like. It is often used in combination with a PLL circuit to select a channel frequency, but this is also within the scope of the present invention.

The single side band mixer 12 may be one that performs a low side wave operation or a high side wave operation according to the phases of + 90 ° and −90 ° of the phase shifter, and the circuit configuration is not particularly limited. Also, the + 90 ° phase shifter 8
And the -90 ° phase shifter 9 may be a combination of a capacitor and a resistor, or a combination of a flip-flop circuit. In one circuit block, a signal whose phase is shifted by + 90 ° and −90 ° is
A device may be devised so as to alternately output in response to the switching signal. Further, instead of using a single phase shifter, a plurality of phase shifters are used to set the phase to + 90 ° and −90.
° It may be devised to output a shifted signal. +90
The phase shifter 8 and the −90 ° phase shifter 9 may be arranged on the high frequency VCO input side of the single side band mixer 12 or on the offset VCO input side.

Phase shifter changeover switches 10 and 1
Reference numeral 1 is for switching the operation state of the single side band mixer 12 between the low side wave operation and the high side wave operation, and its configuration and arrangement are not particularly limited. The switching of the phase shifter depends on whether the transmission and reception bands are A and A 'or B and B', and whether the communication device is in a transmission, reception or standby operation mode. Done. The switching signal is usually supplied from a microcomputer or the like that manages the communication system of the communication device, but this is not particularly limited. In order to reduce current consumption, it is possible to incorporate a function of turning off a power supply such as a high-frequency VCO or an offset VCO in accordance with the timing of the switching signal, but this is also within the scope of the present invention. .

Here, the communication device is a cellular phone,
Refers to communication devices such as cordless telephones and transceivers.

Hereinafter, a second embodiment of the present invention will be described in detail.

The frequency ranges of one transmission band A and one reception band A 'are 940-960 MHz and 810-830 MHz.
z, the other transmission band B and reception band B '
The dual-band transceivers of 940 MHz and 860-885 MHz were configured as shown in FIG.

Note that the actual transceiver device has the configuration shown in FIG.
, An LNA, an RF filter, and the like are required as the reception processing circuit 28, and a quadrature modulator, a power amplifier, and the like are required as the transmission processing circuit 20.

In the second embodiment, the concept of setting the frequency of each oscillator and the operation will be described.

First, the setting of the frequency of each oscillator will be described. The receiving IF signal is set to 130 MHz, and the receiving system is further down-converted to a secondary IF signal of about 500 kHz. Then, an IF signal generator (hereinafter, referred to as an IFVCO) is also required when down-converting a 130 MHz reception IF signal to a 500 kHz secondary IF signal, but in order to minimize the number of signal generators in the entire transceiver. First, f _VCOA is _set to 130 so that the offset VCO-A2 can be used also as an IFVCO.
It was set to 5 MHz.

Next, the difference between the frequency (f _VCOA ) of the offset VCO-A2 and the frequency (f _VCOB ) of the offset VCO-B7, which is a characteristic point of the present embodiment, is the difference between the two transmission bands and the reception. Equal to the difference in band spacing (|
f _VCOA −f _VCOB | = | (| f _Ai −f _A′i | − | f _Bi −f
_B'i |) |), as described above, f _VCOA and f _VCOB
F _VCOB is 7 _MHz greater than f _VCOA because the difference
It was set to 205.5 MHz, which is 5 MHz higher. That is, the frequency of the offset VCO-B7 was set to 205.5 MHz.

Next, the high-frequency VCO-A3 and the high-frequency VCO
The frequency range of -B4 is set from the frequencies of the transmission bands A and B and the frequencies of the offsets VCO-A2 and VCO-B7. First, the high frequency VCO-A3 and the offset VCO-A
2, the single sideband mixer 12 is operated in the high sideband when generating the high frequency signal for the transmission band A. As a result, [transmission band A (940 to 96
0 MHz)]-[Offset VCO-A2 (130.5
MHz) = 809.5 to 829.5 MHz,
The frequency range was CO-A3.

On the other hand, the high frequency VCO-B4 and the offset V
When the CO-B 7 generates the high frequency signal for the transmission band B, the single sideband mixer 12 is operated in the low sideband. As a result, [transmission band B (915
-940 MHz)] + [Offset VCO-B7 (20
5.5 MHz)] = 1120.5 to 1145.5 MHz
Is the frequency range of the high frequency VCO-B4. The frequency of each oscillator was set as described above.

Next, each component of FIG. 2 will be described.

The single side band mixer 12 is shown in FIG.
Although not shown, the high frequency VCO-A3 and the high frequency
The input line from CO-B4 is also provided with a + 90 ° phase shifter, so that offset VCO-A2 and offset VC
When the signal from the O-B 7 is input via the + 90 ° phase shifter 8, it operates in the low sideband, and when it is input via the -90 ° phase shifter 9, it operates in the high sideband. Configured.

Both the + 90 ° phase shift 8 and the −90 ° phase shift 9 were constituted by a network of a capacitor and a resistor.

The phase change switch is constituted by combining a phase shifter change switch 10 and a phase shifter change switch 11 having a simple on / off function.

Further, the operation of each component will be described.

The operation when the transmission band and the reception band are A and A 'is as follows. When transmitting, high frequency VC
The signal of O-A3 (809.5 to 829.5 MHz) and the signal of offset VCO-A2 (130.5 MHz) are mixed by the single sideband mixer 12, at this time, the phase shifter changeover switch 10 is turned off and the phase shifter is changed. The switch 11 was turned on, and the single sideband mixer 12 was operated in the high sideband mode to obtain a high frequency signal (940 to 960 MHz) necessary for transmission.

Further, at the time of reception, the same operation was performed to obtain a high-frequency signal (940 to 960 MHz) necessary for reception.
In this case, the reception signal (810 to 830 MHz) is mixed with the reception high-frequency signal (940 to 960 MHz) by the reception mixer 30 to become an IF signal (130 MHz), and thereafter, necessary demodulation processing is performed.

On the other hand, the transmission band and the reception band are B and B '
The operation when is is as follows. At the time of transmission, high frequency VCO-B4 (1120.5 to 1145.5 MHz)
And the signal of the offset VCO-B7 (205.5 MHz) are mixed by the single sideband mixer 12, at this time, the phase shifter switch 10 is turned on, the phase shifter switch 11 is turned off, and the single sideband mixer 12 is turned off. By operating in the low sideband mode, a high-frequency signal (915-940 MHz) required for transmission was obtained.

At the time of reception, the high-frequency VCO-B4
(1120.5-1145.5 MHz) and offset V
The signal of CO-A2 (130.5 MHz) is mixed by the single sideband mixer 12, and at this time, the phase changeover switch 10 is turned on and the phase changeover switch 11 is turned on.
Is turned off, the single sideband mixer 12 is operated in the low sideband mode, and the high frequency signal (990
-1015 MHz). In this case, the received signal (86
0 to 885 MHz) is a receiving high-frequency signal (990 to 1
015 MHz) and an IF signal (130 MHz) after being mixed by the reception mixer 30, and thereafter required demodulation processing is performed.

According to the second embodiment, in addition to being able to efficiently generate a high-frequency signal required for dual-band transmission and reception, the frequency of the IF
In both cases B and B ', the frequency is equal at 130 MHz, and the configuration of the receiving system after the receiving mixer 30 can be simplified. Further, the offset VCO-A2 (130.
5 MHz) is, as described above, the received IF signal (130M).
Hz) to a secondary IF signal of 500 kHz.

Third Embodiment Hereinafter, a third embodiment of the present invention will be specifically described.

The frequency ranges of one transmission band A and one reception band A 'are 940-960 MHz and 810-830 MHz.
z, the other transmission band B and reception band B '
The dual-band transceivers of 940 MHz and 860-885 MHz were configured as shown in FIG. Compared to FIG. 1 of the first embodiment shown in FIG.
The difference is that an n frequency divider 13 is provided between the CO-A 2 and the mixer 1.

In the third embodiment, as the n frequency divider 13,
The ４ frequency divider for reducing the frequency to １ ／ is configured by combining flip-flop circuits.

Note that the actual transceiver device has the configuration shown in FIG.
, An LNA, an RF filter, and the like are required as the reception processing circuit 28, and a quadrature modulator, a power amplifier, and the like are required as the transmission processing circuit 20.

The setting of the frequency of the offset VCO-A2, which is a feature of this embodiment, will be described below.

In the case of the present embodiment, the difference between the two transmission bands and the reception band is 130 MHz (= | f _Ai −f _A′i
|), 55 MHz (= | f _Bi −f _B′i |), and since an n divider of n = 4 is used, the offset V
The frequency of CO-A2 is set to 300 MHz (= 4 × | (| f _Ai
−f _A′i | − | f _Bi −f _B′i |) |).

Other configurations and operations were performed in the same manner as in the first embodiment.

Embodiment 4 Hereinafter, Embodiment 4 of the present invention will be specifically described.

The frequency ranges of one transmission band A and one reception band A 'are 940-960 MHz and 810-830 MHz.
z, the other transmission band B and reception band B '
The dual-band transceivers of 940 MHz and 860 to 885 MHz were configured as shown in FIG. As compared with FIG. 2 of the second embodiment shown in FIG.
The difference is that an n frequency divider 13 is provided between the CO-A2 and the offset VCO-B7 and the changeover switch 10 and the changeover switch 11.

In the fourth embodiment, the n frequency divider 13
The divide-by-two frequency divider for reducing the frequency by half is configured by combining flip-flop circuits.

Note that the actual transceiver device has the configuration shown in FIG.
, An LNA, an FR filter, and the like are required as the reception processing circuit 28, and a quadrature modulator, a power amplifier, and the like are required as the transmission processing circuit 20.

The concept of setting the frequency of each oscillator in this embodiment will be described below.

First, the reception IF signal is set to 130 MHz,
This is used as a receiving system for further down-converting to a secondary IF signal of about 500 kHz. Then, when down-converting the received IF signal of 130 MHz to a secondary IF signal of 500 kHz, an IF signal generator (hereinafter, IFVCO) is also used.
Is required). 130.5 MHz was selected as the frequency of the IFVCO. By the way, it is desired to reduce the number of signal generators as much as possible in the whole transceiver. Therefore,
The signal from the offset VCO-A2 is divided into n
The frequency-divided signal is used instead of the signal from the IFVCO. In this embodiment, since n = 2, f _VCOA is set to 261M which is twice the frequency of the IFVCO.
Hz.

Next, the difference between the frequencies of the offset VCO-A2 and the offset VCO-B7, which is a feature of the present embodiment, is n times (n is 2 or more) the difference between the intervals between the two transmission bands and the reception band. , The frequency of the offset VCO-B7 was set. That is, in the case of the present embodiment, the difference between the two transmission bands and the reception band is 130 MHz (= | f _Ai −f _A′i |), 5
5 MHz (= | f _Bi −f _{B ′ i} |) and the difference is 75 MHz
Since the frequency divider of n = 2 is used, the frequency of the offset VCO-B7 is set to 411 MHz (= 2 × |
(| F _Ai -f _A'i |-| f _Bi -f _B'i |) | +261)
Set to.

Other configurations and operations were performed in the same manner as in the second embodiment.

Fifth Embodiment FIG. 5 is a block diagram showing a fifth embodiment of the present invention. In the figure, reference numeral 51 denotes a mixer composed of two double side band mixers 51A and 51B and a coupler 51C. 52 and 53 are high frequency VCOs,
54 is an offset VCO, 55 and 56 are buffer circuits, 57 and 58 are 90 ° phase shift circuits, 59 is a double sideband mixer, 60 is a reception mixer, 61 is a reception processing circuit, 62 is a 90 ° phase shift circuit 57, 58
And a control circuit for controlling the double sideband mixer 59, and 71 and 72 are closing switches. In addition, reference numeral 80 exemplifies a transmitting-side modulation circuit.

Next, a specific operation of the fifth embodiment will be described.

In the embodiment shown in FIG. 5, as a dual-band transceiver, the frequency ranges of one transmission band and reception band (A and A ') and the other transmission band and reception band (B and B') are used. To 9
40-960 MHz (= A), 810-830 MHz
(= A '), 925-940 MHz (= B), 870-
885 MHz (= B ') was set. In the actual transceiver, in addition to the blocks described in FIG. 5, in the receiving system, an LNA, an IF filter, an IF amplifier, etc.
In the transmission system, a circuit with a quadrature modulator, a power amplifier, and the like are required, but are omitted from FIG. 5 because they are not involved in the present invention.

In the present embodiment, the difference between the two transmission bands and the reception band is 130 MHz (= | f _Ai −f _A′i
|), 55 MHz (= | f _Bi −f _B′i |), the frequency of the offset VCO 54 is set to 75 MHz.
z (= | (| f _Ai -f _A'i |-| f _Bi -f _B'i |) |)
Set to.

As the mixer 51, a low sideband single sideband mixer was used. The high frequency VCO has a frequency range of 1015 to 1035 MHz and a frequency range of 10
Two high-frequency VCOs 52 and 53 of 00 to 1015 MHz
Was used. The high frequency signal changeover switch function for reception is
This is realized by controlling the supply of current from the control circuit 62 to each circuit.

The operation when the transmission band and the reception band are A and A 'in the dual band transceiver constructed as shown in FIG. 5 is as described below.

At the time of transmission, high-frequency signals (1015 to 1015)
35 MHz) and an offset signal (75 MHz) are received by a buffer circuit 55 and a buffer circuit 56, and the output is mixed by a low sideband single sideband mixer 51 to obtain a high frequency signal (940 to 960MHz) necessary for transmission. . Also, at the time of reception, the high-frequency VCO 52 (1015 to
1035MHz) and offset VCO54 (75MH)
z) is mixed by the double sideband mixer 59,
High frequency signals (940-960 MHz) were obtained. In this case, the reception signal (810 to 830 MHz) is mixed with the reception high frequency signal (940 to 960 MHz) by the reception mixer 60 to become an IF signal (130 MHz), and thereafter, necessary demodulation processing (not shown) is performed. You.

On the other hand, the transmission band and the reception band are B and B '
Is as follows.

At the time of transmission, the high-frequency VCO 53 (1000
1015 MHz) and offset VCO 54 (75 MHz)
z) the low sideband single sideband mixer 51
And a high-frequency signal (925 to 940) necessary for transmission.
MHz). At the time of reception, the high-frequency VCO 53
(1000 to 1015 MHz), a high-frequency signal (1000 to 1015 MHz) necessary for reception was obtained as it was.
In this case, the reception signal (870 to 885 MHz) is mixed with the reception high frequency signal (1000 to 1015 MHz) by the reception mixer 60 to become an IF signal (130 MHz), and thereafter, necessary demodulation processing (not shown) is performed. You.

As shown in the fifth embodiment, in addition to generating a high frequency signal required for dual band transmission and reception with a minimum block configuration, the frequency of the IF signal is ′, In either case, 1
It is equal to 30 MHz, and the configuration of the receiving system after the receiving mixer can be simplified.

In order to realize the function of the single sideband mixer, a high frequency signal is converted into two outputs, and a phase shift circuit 57 for making the phase difference 90 degrees.
And a phase shift circuit 58 that converts the offset signal into two outputs and makes the phase difference 90 degrees, and inputs those output signals to the mixer 51. However, the present invention is not limited to the above-described circuit configuration, that is, a structure having two mixers and combining their output units.

In the receiving mixer 60, in order to amplify a weak received signal, a required signal for frequency conversion is required to have high accuracy and a low unnecessary wave. Therefore, it is necessary to dispose a filter (not shown) between the reception mixer 60 and the mixer 59 for synthesizing the reception signal, and to remove unnecessary waves.

In the double sideband mixer 59, two mixers 51 used in the single sideband mixer are used.
Since only one A, 51B is used, current consumption can be reduced to half or less.

Embodiment 6 FIG. 6 is a block diagram showing an embodiment of the present invention.
This figure is different from FIG. 5 in that the double sideband mixer 59
And a new control circuit 65 is provided.

That is, in order to obtain a reception signal to be supplied to the reception mixer 60, as shown in FIG. 6, the current of the current source section of one of the mixers constituting the single sideband mixer 51 is converted into a signal from the control circuit. It is also feasible to lower it.

In the embodiments shown in FIGS. 5 and 6, the buffer circuit 55 and the phase shift circuit 57 are separately formed, but the two circuits are integrated and the phase shift circuit is It is also possible to adopt a configuration in which one of the two output units is controlled by a signal from a control circuit.

Further, an example has been described in which a current source (not shown) is controlled as a control circuit. However, a similar function can be achieved by using a switch circuit.

[0101]

As described above, according to the present invention, there is provided a small, lightweight, low-cost, and low-power-consumption communication device that can support a dual band in which the transmission band and the reception band have different frequency intervals. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram showing Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a block diagram showing a third embodiment of the present invention.

FIG. 4 is a block diagram showing a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing a sixth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mixer 2 offset VCO-A 3 high-frequency VCO-A 4 high-frequency VCO-B 5 high-frequency signal switch for reception 6 high-frequency signal switch for reception 7 offset VCO-B 8 + 90 ° phase shifter 9 −90 ° phase shifter 10 phase shifter Changeover switch 11 Phase shifter changeover switch 12 Single sideband mixer 13 1 / n frequency divider 20 Transmission system processing circuit 28 Receiving system processing circuit 30 Receiving mixer 51 Low sideband single sideband mixer 52 High frequency VCO 53 High frequency VCO 54 Offset VCO 55, 56 Buffer circuit 57, 58 90 ° phase shift circuit 59 Double sideband mixer 60 Receive mixer 62, 65 Control circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuo Saito 2-1, Samejima, Fuji City, Shizuoka Prefecture Asahi Kasei Industry Co., Ltd. (72) Inventor Kenichi Takahashi 1-24-10 Yoyogi, Shibuya-ku, Tokyo Asahi Kasei Micro Inside System Co., Ltd. (72) Inventor Norihiko Mikoshiba Asahi Kasei Microsystem Co., Ltd. 1-24-10 Yoyogi, Shibuya-ku, Tokyo

Claims (16)

[Claims] 1. A pair of transmission bands A (frequency range: f _A1
To f _A2 ) and the reception band A ′ (frequency range: f _A′1 to
f _A′2 ) and a first communication band including a pair of transmission bands B (frequency range f _{B1 to} f _B2 ) and reception band B ′ (frequency range: f _{B′1 to} f _B′2 ). Communication device having two communication bands (provided that | f _Ai −f _A′i | ≠ | f _Bi −
f _B′i |, i = 1 or 2), wherein: a first variable frequency oscillator having a first oscillation frequency range; a second variable frequency oscillator having a second oscillation frequency range; Offset frequency f _OS (f _OS = | (f _Ai −f _A′i ) | −
| F _Bi −f _B′i |) |), one of the first variable frequency oscillator and the second variable frequency oscillator, and a signal output from the offset oscillator. A mixer circuit for inputting, and a switch circuit for extracting an output signal of the mixer circuit or an output signal of the first variable frequency oscillator or the second variable frequency oscillator as a local oscillation signal. Communication device. 2. The apparatus according to claim 1, further comprising a reception mixer circuit for receiving the high-frequency signal received and the signal output from the switch circuit and outputting an IF signal. Communication device. 3. The communication device according to claim 1, wherein a voltage controlled oscillator (VCO) is used as the first variable frequency oscillator, the second variable frequency oscillator, and the offset oscillator. 4. The method according to claim 1, wherein
A communication device for executing communication by FDD (frequency division duplex) or TDMA (time division multiple access) communication method. 5. The method according to claim 1, wherein an oscillation frequency f _OS of the offset oscillator is set to be equal to n times a difference between an interval between the two transmission bands and the reception band (n natural number of n ≧ 2) (f _OS = n | (| f _Ai -f _A'i |-| f _Bi -f _B'i
|) |), Input to the mixer circuit via a separately provided n-frequency divider circuit. 6. The communication device according to claim 1, wherein a single sideband mixer is used as the mixer circuit. 7. The transmission band A according to claim 1, wherein the transmission band A is 940 to 960 MHz and the transmission band B is 915 to 960 MHz.
40 MHz, the receiving band A 'is 810-830 MH
z, the reception band B 'is 860-885 MHz, and any of the variable frequency oscillators is 990-103 MHz.
A communication device which covers a range of 5 MHz, has a frequency f _{OS of the} offset oscillator which is m times as large as 75 MHz (m is a natural number), and has an m frequency dividing circuit only when m ≧ 2. . 8. A pair of transmission bands A (frequency range: f _A1
To f _A2 ) and the reception band A ′ (frequency range: f _A′1 to
f _A′2 ) and a first communication band including a pair of transmission bands B (frequency range f _{B1 to} f _B2 ) and reception band B ′ (frequency range: f _{B′1 to} f _B′2 ). Communication device having two communication bands (provided that | f _Ai −f _A′i | ≠ | f _Bi −
f _B′i |, i = 1 or 2), wherein a single having a first and a second variable frequency oscillator, a first and a second offset oscillator, a + 90 ° phase shifter and a −90 ° phase shifter A sideband mixer circuit; and a changeover switch for selecting one of the phase shifters, wherein a difference between a frequency (f _VCOA ) of the first offset oscillator and a frequency (f _VCOB ) of the second offset oscillator is provided. _Is equal to the difference between the intervals between the two transmission bands and the reception band (| f _VCOA -f _VCOB | = | (| f _Ai -f _A'i |-| f _{Bi
-F B'i} |) |) | 9. The apparatus according to claim 8, wherein a difference between the frequency (f _VCOA ) of the first offset oscillator and the frequency (f _VCOB ) of the second offset oscillator is obtained by calculating a difference between an interval between the two transmission bands and a reception band. N times the difference (n is a natural number and n ≧ 2)
(| F _VCOA -f _VCOB | = n | (| f _Ai -f _A'i
| − | F _Bi −f _B′i |) |), and inputs the signal to the single sideband mixer circuit via a separately provided n _{frequency dividing} circuit. 10. The voltage controlled oscillator (VCO) according to claim 8, wherein said first and second variable frequency oscillators and said first and second offset oscillators are provided.
A communication device characterized by using: 11. The communication device according to claim 8, wherein communication is performed by an FDD (frequency division duplex) or TDMA (time division multiple access) communication method. 12. The communication device according to claim 1, wherein the communication device is used as a transceiver device. 13. The communication device according to claim 1, wherein the functions of the first and second variable frequency oscillators are provided in a single variable frequency oscillator. 14. In a communication device corresponding to a dual band in which frequency intervals of a transmission band and a reception band are different from each other, a frequency synthesizer included in the communication device outputs a single sideband signal and / or a double sideband signal. A communication device comprising a mixer circuit. 15. The mixer circuit according to claim 14, wherein the mixer circuit includes a single side band mixer and a double side band mixer, and selectively outputs an output signal of the single side band mixer or an output of the double side band mixer. A communication device comprising a switch circuit for taking out. 16. The single side band mixer according to claim 15, wherein the single side band mixer comprises two double side band mixers having an output unit coupled thereto, and the function of one of the two double side band mixers is stopped. A communication device used as a double sideband mixer.