JP3092538B2 - Communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device having a temperature-compensated piezoelectric oscillation circuit that oscillates a highly stable frequency, such as an automobile telephone device or a pager.

[0002]

2. Description of the Related Art A conventional communication device will be described with reference to the block diagram of FIG. 5 and FIG. 6 showing its operation. In order to maintain a stable transmission frequency and a stable reception frequency, the communication apparatus uses a local oscillation circuit 115 and a PLL reference oscillation circuit 111 of the PLL synthesizers 106 and 110.
A temperature-compensated piezoelectric oscillation circuit that oscillates a highly stable frequency is used. In addition, the synchronous clock source for encoding the transmission data and the synchronous clock source for decoding the received data are also provided with a synchronous signal of the encoder 125 or the decoder 120 in order to prevent synchronization deviation during data communication and reduce data communication errors. The oscillation circuit 126 uses a temperature-compensated piezoelectric oscillation circuit that oscillates a highly stable frequency.

[0003] Here, the conventional communication apparatus includes a transmission timing or a reception timing, a transmission data encoding process or a reception data decoding process, and a timing for controlling the oscillation frequency of the temperature-compensated piezoelectric oscillation circuit. 132 was asynchronous. In other words, the oscillation frequency of the temperature-compensated piezoelectric oscillation circuit is controlled regardless of whether the communication device is performing a transmission operation or a reception operation, a transmission data encoding operation or a reception data decoding operation, or a stop. ing.

A temperature-compensated piezoelectric oscillation circuit detects an ambient temperature and uses a CPU or R based on this temperature data.
A temperature-compensated piezoelectric oscillation circuit that oscillates a stable frequency over a wide temperature range by converting the frequency into a frequency control signal using an OM or the like and controlling the oscillation frequency by the frequency control signal is often used.

[0005]

However, the conventional communication device requires a temperature-compensated piezoelectric oscillation circuit during a transmission operation, a reception operation, a transmission data encoding operation, and a reception data decoding operation. The oscillation frequency may be controlled. At this time, the temperature-compensated piezoelectric oscillation circuit generates a frequency variation (FM noise) and a phase variation (PM noise) that occur at the moment when the oscillation frequency control is performed. Due to the frequency fluctuation and the phase fluctuation, the transmission frequency and the receiving frequency simultaneously have a frequency fluctuation and a phase fluctuation. Also, in the encoding process of the transmission data and the decoding process of the reception data, if the synchronization clock fluctuates, the synchronization deviation of the communication occurs. As a result, fluctuations in the communication frequency and a reduction in communication sensitivity due to synchronization deviation, and fluctuations in the transmission frequency lead to adverse effects on communication such as interference with communication using other frequencies.

As a method of preventing this, there is a method of reducing the frequency control amount of the temperature-compensated piezoelectric oscillation circuit to reduce the frequency fluctuation and phase fluctuation occurring at the moment of frequency control, thereby reducing the adverse effect on communication. However, in this case, the resolution of the temperature measurement and the resolution of the frequency control amount must be increased, the amount of data to be handled increases, and a temperature measuring device with high temperature measurement sensitivity is required. Must be finely controlled, and the circuit configuration is inevitably complicated and fine, which imposes manufacturing limitations and is expensive.

An object of the present invention is to provide a communication device that avoids the adverse effects of frequency fluctuation and phase fluctuation that occur during frequency control of a temperature-compensated piezoelectric oscillator in order to solve the above problems.

[0008]

According to the present invention, there is provided a communication apparatus having a temperature-compensated piezoelectric oscillation circuit, comprising: a PLL reference oscillation circuit which operates based on an output frequency of the temperature-compensated piezoelectric oscillation circuit; A transmission PLL synthesizer and a reception PLL synthesizer that operate based on an output frequency of a PLL reference oscillation circuit; and a control circuit that generates a frequency control signal for performing temperature compensation of the temperature compensation type piezoelectric oscillation circuit. When the state represented by the transmission timing signal is stopped and the state represented by the radio wave reception timing signal is stopped, the frequency control of the temperature compensated piezoelectric oscillation circuit is performed by the frequency control signal generated from the control circuit. It is characterized by.

Further, the communication device has a second local oscillation circuit having a second temperature-compensated piezoelectric oscillation circuit, wherein the state indicated by the radio wave transmission timing signal is stopped, and the state indicated by the radio wave reception timing signal is indicated. Is stopped, the frequency control of the second temperature-compensated piezoelectric oscillation circuit is performed by the frequency control signal generated from the control circuit. A synchronization signal oscillating circuit including a third temperature-compensated piezoelectric oscillation circuit; a decoder and an encoder for processing data with a clock from the synchronization signal oscillating circuit; Is stopped and the state represented by the decode processing timing signal is stopped, the frequency control of the third temperature compensated piezoelectric oscillation circuit is performed by the second frequency control signal generated from the control circuit. Features.

[0010]

The timing of performing the frequency control of the temperature-compensated piezoelectric oscillation circuit is controlled from an external control circuit, and the frequency control of the temperature-compensated piezoelectric oscillation circuit does not adversely affect the communication of the communication device, that is, during non-transmission operation. Alternatively, the frequency control is performed during the non-reception operation, and the frequency control is not performed during the transmission operation or the reception operation. Therefore, even if there is a frequency fluctuation or a phase fluctuation during the frequency control, and even if the fluctuation amount is large, there is no adverse effect on the communication.

As a result, it is possible to avoid frequency fluctuations and phase fluctuations while keeping the transmission frequency, reception frequency, or data synchronization frequency highly stable.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

As an embodiment, a car telephone as a transmitting / receiving apparatus will be described with reference to a block diagram of FIG. 1 and a timing chart of FIG. FIG. 1 is a block diagram of a car telephone, wherein 1 is an antenna, 2 is a distributor for transmission and reception signals, 3 is a bandpass filter,
Is an RF amplifier, and 5 is a first mixer. 5 is the receiving side PL
It is an L synthesizer and functions as a first local oscillation circuit in the receiving circuit, and can set the oscillation frequency in a programmable manner, thereby enabling switching of the receiving frequency, that is, so-called receiving channel switching. Reference numeral 7 denotes a transmission band-pass filter, 8 denotes a transmission amplifier, and 9 denotes a transmission data modulation mixer that combines a carrier signal and transmission data. Reference numeral 10 denotes a transmission-side PLL synthesizer which functions to generate a carrier signal of a transmission radio wave and can set an oscillation frequency in a programmable manner, thereby enabling transmission frequency switching, that is, transmission channel switching. Reference numeral 11 denotes a PLL reference oscillation circuit which is a temperature-compensated piezoelectric oscillation circuit, and supplies a reference clock to the PLL synthesizers 6 and 10. The PLL synthesizers 6 and 10 determine the oscillation frequency based on the reference clock supplied from the 11 PLL reference oscillation circuits, and also determine the channel step amount. Therefore, a stable oscillation frequency is required for the 11 PLL reference clocks. 12 is a bandpass filter of the first intermediate frequency, 13 is an amplifier of the first intermediate frequency,
14 is a second mixer. Reference numeral 15 denotes a second local oscillation circuit, which uses a temperature-compensated piezoelectric oscillation circuit to maintain a stable reception frequency. 16 is a bandpass filter of the second intermediate frequency, 17 is an amplifier of the second intermediate frequency, 18 is a detection circuit, and 19 is a low-pass filter of a baseband. 2
Reference numeral 0 denotes a decoder circuit for receiving data that converts a received signal that has passed from the antenna 1 to the low-pass filter 19 into voice, numbers, characters, or the like. Reference numeral 21 denotes a speaker for outputting sound, and reference numeral 22 denotes a display for displaying numbers and characters. Reference numeral 23 denotes a keyboard for inputting data such as numbers and characters, and reference numeral 24 denotes a microphone for inputting voice. Reference numeral 25 denotes a signal capable of transmitting transmission data input from a keyboard 23 and a microphone 24 by radio waves, for example, F
This is a transmission data encoder circuit that performs M and PM modulation and performs processing such as data encryption. Reference numeral 26 denotes a synchronization signal oscillation circuit that supplies a synchronization clock for signal processing to 20 decoders and 25 encoders. 2
The decoder of 0 and the encoder of 25 perform data processing based on the clock from the synchronization signal oscillation circuit of 26. Therefore, a stable oscillation frequency is required to prevent synchronization deviation and reduce communication errors. Type piezoelectric oscillation circuit is used. Reference numeral 27 denotes a CPU as a control circuit for controlling the entire communication device. The CPU 27 controls the PLL synthesizers 6 and 10, the decoder 20 and the encoder 25. In addition, the PLL reference oscillator circuit 11 and the second local oscillator 15 The timing for controlling the frequency of the circuit and the synchronization signal oscillating circuit 26 can be controlled.
In FIG. 1, 30 is a PLL reference oscillation circuit of 11 and 15 is a second reference oscillation circuit.
A control line for controlling the timing of controlling the frequency of the local oscillation circuit, and a control line 31 for controlling the timing of controlling the frequency of the 26 synchronization signal oscillation circuit.

With the above configuration, the car telephone as the transmitting / receiving device can be provided with 11 PLL reference oscillation circuits and 15
The three types of temperature-compensated piezoelectric oscillation circuits of the second local oscillation circuit and the synchronization signal oscillation circuit of 26 are provided. This can be performed when it is not necessary, and can be omitted when a stable oscillation frequency is required.

The operation at this time will be described with reference to the timing chart of FIG. The radio wave transmission timing indicates whether the transmission circuit that operates from the modulation mixer 9, the transmission-side PLL synthesizer 10, and the antenna 1 and transmits transmission data as radio waves is operating or stopped. The encoding processing timing indicates whether the encoding processing of the transmission data is in operation or stopped by the 25 encoders. The timing of radio wave reception
Indicates whether the receiving circuit from the antenna 1 to the 19 low-pass filter is operating or stopped. The decoding processing timing indicates whether the decoding processing of the received data by the 20 decoders is operating or stopped. Here, when the radio wave transmission and the encoding process are operating, it is called a transmission operation, and when it is stopped, it is called a non-transmission operation. Also, when the radio wave receiving and decoding processing is operating, it is called a receiving operation, and when it is stopped, it is called a non-receiving operation. Now, while the radio wave transmission is operating, the 11 PLL reference oscillation circuits need to oscillate a stable frequency. or,
While the radio wave reception is operating, 11 PLL reference oscillation circuits and 1
The second local oscillation circuit of No. 5 needs to oscillate a stable frequency. Therefore, the frequency control 32 of the 11 PLL reference oscillation circuit is performed while the radio wave transmission and the radio wave reception are stopped, and the frequency control 32 is not performed during the operation.
Further, the frequency control 32 of the second local oscillation circuit 15 may be performed while radio wave reception is stopped, and the frequency control 32 may not be performed during operation. Since the mobile phone of this embodiment performs simultaneous transmission and reception, the above operation is realized by one control line 30. Next, during the transmission data encoding operation and the reception data decoding operation, the 26 synchronizing signal oscillation circuits need to oscillate a stable frequency.
Therefore, the frequency control 32 of the synchronization signal oscillation circuit 26 may be performed when the encoding process and the decoding process are stopped, and the frequency control 32 may not be performed during the operation. In the present embodiment, since the synchronous signal oscillation circuit of the encoder and the decoder is shared, it is necessary to perform the frequency control 32 when the encoding and decoding processes are simultaneously stopped. Operation is realized. By operating as described above, 11 PLLs
The reference oscillation circuit, the second local oscillation circuit of 15 and the synchronization signal oscillation circuit of 26 generate frequency fluctuations and phase fluctuations at the time of frequency control 32, but the car phone as a communication device is operating at that time. There is no adverse effect. Conversely, when the mobile phone is operating, the frequency control 32 is not performed, and each oscillation circuit oscillates at a stable frequency, so that stable operation is guaranteed.

In the above embodiment, the timing 32 of the frequency control is controlled depending on whether the transmission / reception circuit or the encoder / decoder circuit is operating or stopped. The following example,
A description will be given of a TDMA-type or DSI-type communication device in which the circuit is operating but data is intermittently taken in.

FIG. 3 shows TDMA (Time Division).
6 is a timing chart showing an embodiment in a time-division multiple access system. T
The DMA is a time compression type communication method for communicating data of n communication devices at a certain time. In this system, when the radio wave of the own communication data (required data) is received and the data is decoded, that is, during the reception operation, the frequency control 32 of the temperature-compensated piezoelectric oscillation circuit is not performed, and the other communication device is not controlled. The frequency control 32 is performed when the communication data is being transmitted and when the receiving operation is stopped, that is, during the non-receiving operation. By such timing control of the frequency control 32, the frequency control at the time of frequency control 3
2, the adverse effects of the frequency fluctuation and the phase fluctuation are avoided, stable supply of frequency oscillation is obtained, and stable operation is guaranteed.

Next, FIG. 4 shows a DSI (Digital S).
6 is a timing chart showing an embodiment in a digital speech interruption method. DSI is a time compression type communication system in which data of another speaker is interrupted when the speaker is silent. Also in this system, the frequency control 32 of the temperature-compensated piezoelectric oscillation circuit is not performed when necessary data is being received, that is, during the receiving operation, as in the TDMA system, and the frequency control 32 is performed at other times, that is, during the non-receiving operation. To By such control, the same effect as in the TDMA system can be obtained. The temperature-compensated piezoelectric oscillation circuit used in the oscillation circuit according to the present embodiment detects an ambient temperature and detects C based on this temperature data.
A temperature-compensated piezoelectric oscillation circuit that oscillates a stable frequency in a wide temperature range by converting the frequency into a frequency control signal using a PU or a ROM and controlling the oscillation frequency by the frequency control signal is often used. As a frequency control method, a load capacitance of the piezoelectric vibrator is changed using either a variable capacitance diode or a fixed capacitor group. In order to simplify the circuit configuration, the capacitance of the variable capacitance diode can be varied in a short time, or when switching the group of fixed capacitors, if a capacitor with a large capacitance value is switched, large frequency fluctuations and phase fluctuations occur at that time, that is, during frequency control. However, this embodiment can avoid the adverse effect. Since the capacity can be largely changed and the frequency change amount can be increased, the number of temperature measurement points can be reduced and the amount of data to be handled can be reduced. Therefore, the fact that the frequency variation and the phase variation during the frequency control of the temperature-compensated piezoelectric oscillation circuit may be large means that the circuit configuration of the temperature-compensated piezoelectric oscillation circuit can be simplified, and the size, weight and cost can be reduced.

In the embodiment, a car telephone as a transmission / reception device has been described as an example.
It can also be used for a PS receiver or a remote controller for a transmission-only device.

In this embodiment, a wireless communication device has been described as an example. However, similar applications and effects can be obtained with a wired communication device.

In this embodiment, the CPU has been described as an example of a control circuit for controlling the timing for controlling the frequency of the temperature-compensated piezoelectric oscillation circuit. However, the frequency of the oscillation circuit is stable in the operation of the communication device. The circuit need not be a CPU as long as it can determine whether it is necessary or whether there is a frequency variation and a phase variation. It can be replaced by, for example, an encoder or a decoder or a transmission switch or a reception switch.

[0022]

According to the present invention, as described above, the timing for controlling the frequency of the temperature-compensated piezoelectric oscillation circuit of the communication device can be controlled from an external control circuit. The configuration is such that the frequency control is not performed during the transmission operation or the reception operation during the non-transmission operation or the non-reception operation of the communication device, and the adverse effect of the frequency fluctuation and the phase fluctuation generated when controlling the frequency is avoided. And stable operation is compensated by supplying a stable frequency. Furthermore, for the temperature-compensated piezoelectric oscillation circuit, the amount of frequency fluctuation and phase fluctuation generated during frequency control may be large, so that the circuit configuration is simplified and the size, weight and cost can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a timing chart showing the operation of one embodiment of the communication device of the present invention.

FIG. 3 is a timing chart showing an operation of one embodiment in a TDMA system.

FIG. 4 is a timing chart showing the operation of one embodiment using the DSI method.

FIG. 5 is a block diagram showing a conventional communication device.

FIG. 6 is a timing chart showing an operation of a conventional communication device.

[Explanation of symbols]

 1, 101: Antenna 2, 102: Distributor 3, 103: Bunt pass filter 4, 104: RF amplifier 5, 105: First mixer 6, 106: Receiving PLL Synthesizer 7, 107: transmission stage band pass filter 8, 108: transmission amplifier 9, 109: modulation mixer 10, 11o ... transmission side PLL synthesizer 11, 111: PLL reference oscillation circuit 12 , 112: first intermediate frequency bandpass filter 13, 113: first intermediate frequency amplifier 14, 114: second mixer 15, 115: second local oscillator 16, 116: second Intermediate frequency band-pass filters 17, 117: Second intermediate frequency amplifiers 18, 118: Detection circuits 19, 119: Base band low-pass filters 20, 12 0: Decoder 21, 121: Speaker 22, 122: Display 23, 123: Keyboard 24, 124: Microphone 25, 125: Encoder 26, 126: Synchronous signal oscillation Circuits 27, 127 ... CPU 30, 31 ... Control lines 32, 132 ... Frequency control timing

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H04B 1/16 H04B 1/16 Z 1/40 1/40 7/26 7/26 N

Claims (3)

(57) [Claims] 1. A communication device having a temperature-compensated piezoelectric oscillation circuit, wherein the PLL-based oscillation circuit operates based on an output frequency of the temperature-compensated piezoelectric oscillation circuit, and operates based on an output frequency of the PLL reference oscillation circuit. A PLL synthesizer for transmission and a PLL synthesizer for reception, and a control circuit for generating a frequency control signal for performing temperature compensation of the temperature-compensated piezoelectric oscillation circuit, wherein the state represented by the radio wave transmission timing signal is stopped, and A communication device, wherein when the state represented by the radio wave reception timing signal is stopped, the frequency control of the temperature compensated piezoelectric oscillation circuit is performed by the frequency control signal generated from the control circuit. 2. The communication device according to claim 1, further comprising a second local oscillation circuit including a second temperature-compensated piezoelectric oscillation circuit, wherein a state indicated by the radio wave transmission timing signal is stopped, and A communication device, wherein when the state indicated by the radio wave reception timing signal is stopped, the frequency control of the second temperature-compensated piezoelectric oscillation circuit is performed by the frequency control signal generated from the control circuit. 3. The communication device according to claim 1, further comprising: a synchronization signal oscillation circuit including a third temperature-compensated piezoelectric oscillation circuit; and a clock signal from the synchronization signal oscillation circuit. A second frequency control generated by the control circuit when a state represented by the encoding processing timing signal is stopped and a state represented by the decoding processing timing signal is stopped. A communication device for controlling the frequency of the third temperature-compensated piezoelectric oscillation circuit by a signal.