JPH08251067A - Portable telephone set - Google Patents

Abstract

PURPOSE: To obtain a portable telephone set which is reduced in power consumption and has small spurious radiation at the time of transmission and reception. CONSTITUTION: A variable AMP control circuit 105 varies the gains of variable attenuation circuits 101a and 101b according to received electric field intensity. Consequently, the gains of the variable attenuation circuits 101a and 101b are adjusted, so leaks in mixers (5) 35 and (1) 7 in following stages are reduced and the isolation between a PLLA circuit and a PLLB circuit is improved. Consequently, the spurious radiation is small at the time of transmission and reception. Further, a power source control circuit 106 controls power supply to PLLAMPs 102a and 102b according to transmission and reception timing, so neither the PLLAMP 102a nor 102b consumes electric power except in its transmission and reception timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile telephone which uses a plurality of time-divided communication slots in digital mobile communication.

[0002]

2. Description of the Related Art In recent years, circuit miniaturization and low power consumption technology have become important in digital mobile communication such as mobile phones. FIG. 4 is a block diagram showing a configuration of a main part of a conventional mobile phone. In this mobile phone, TDMA (Time D
ivison Multiple Acces: Time-division multiplex transmission) bidirectional communication is performed. In the figure, the upper part shows a receiving circuit, the middle part shows a transmission / reception common circuit, and the lower part shows a transmitting circuit.

The structure and operation of this portable telephone will be roughly divided into a receiving circuit, a transmission / reception common circuit, and a transmitting circuit.
First, in the receiving circuit, antenna 1 → transmission / reception filter 2 → antenna switch 3 → input amplifier 4 → reception filter 5 → R
Only the received high frequency signal is extracted via the F (high frequency) amplifier 6. Next, a VCO (Voltage Controled Oscilator) in a PLL circuit (which also serves as a frequency modulator here) having an internal configuration surrounded by a one-dot chain line
That is, the reference frequency signal for mixing (that is, the frequency signal for selecting the receiving channel) supplied from 21 → fixed attenuation circuit 26 → PLLAMP 27 is input to the mixer 7. The first-stage frequency mixing is performed (that is, only the difference in the frequency spectrum generated by using the non-linear portion of the transistor is extracted), and further, the first IF (intermediate frequency) filter 8 → the first IF amplifier 9 The first intermediate frequency signal (first IF signal) is taken out via (provided for amplifying the output whose level has been reduced by the passage loss of the filter).

Subsequently, the extracted first IF signal is input to the mixer 12a via the mixer 10 → second IF filter 11. In the mixer 12a, the second IFP
The mixing frequency signal supplied from the LL 18 (reference frequency oscillator for the second intermediate frequency) and the second-stage frequency mixing are performed, and the third intermediate frequency signal (third IF signal) is passed through the third IF filter 13. ) Is taken out.

Further, the extracted third IF signal is amplitude-adjusted by the third IF amplifier 14 → limiter amplifier 15, demodulated by the demodulator 16, and then waveform-shaped in the reception processing unit 17 of the voice or non-voice signal. The digital waveform is converted into an analog signal by the device and output as a voice or non-voice signal. Also, in the case of data, it is designed to be input to the required device.

Further, the extracted third IF signal is subjected to the electric field strength (signal level) of the carrier wave by the carrier wave level detector 19.
Is measured. The carrier level detector 19 is a receiving signal strength indicator (RSSI) indicating the received electric field strength.
control device 2 that controls the entire transmitter / receiver circuit
Output to 0. The control device 20 is a signal processing device, and here, the reception processing device 1 for audio or non-audio signals.
7. Supplying synthesizer data to the frequency divider and phase comparator 24 in the PLL circuit, the variable attenuator 31, and the display and operation / instruction device 39 (the user operates the switch 20 to turn on / off the controller 20 to operate the controller 20). In addition, various necessary items are displayed), and control such as switching of power supply during a transmission / reception period by a power supply circuit (not shown) is performed.

In the PLL circuit, the reference signal supplied from the PLL reference signal generator 25 is phase-compared with the frequency-divided signal of the output returned from the VCO 21 in the frequency divider / phase comparator 24. The comparison result is passed through a low-pass filter (LPF) 23 → mixer 22 to obtain a VCO
21 is supplied as a voltage control signal for frequency adjustment. Then, the frequency signals for selecting the reception and transmission frequencies are sent from the VCO 21 to the mixer 7 and the mixer 34.
To be supplied to.

On the other hand, in the transmission circuit, the input voice or non-voice signal is converted from an analog signal into a digital waveform by the voice or non-voice signal transmission processing device 28, and in the case of transmission data, the data is converted. Processed, and further modulator 29 → DAC 30 → fourth filter (BPF) 3
It is adapted to be input to the mixer 32 via 1.
Then, in the mixer 32, the fourth filter (BPF
) 32 and the signal from the second IFPLL 18 are mixed.

Next, the desired frequency by the VCO 21 is
Fixed attenuator circuit 26-> PLLAMP 27 and then mixer 3
4 is input. The mixer 34 mixes the desired frequency and the signal from the third filter (BPF) to convert it into a transmission frequency. Furthermore, the second filter (B
PF) 35-> transmission amplifier 36-> first filter (BP
F) A transmission signal is sent from the antenna 1 to the communication partner via the 37 → antenna switch 3 → transmission / reception filter 2.

Further, in comparison with the above-mentioned conventional mobile phone, P
There is also a mobile phone in which the circuit portion including the LL circuit (VCO 21, LPF 23, frequency divider and phase comparator 24), fixed attenuation circuit 26, and PLLAMP 27 is duplicated.
It is duplicated because carrier waves of different frequencies are used for a channel for controlling connection (control channel) and a channel for communication or data transmission / reception (communication channel). That is, each frequency of the control channel and the communication channel corresponds to each of the duplicated circuit portions. This makes it possible to smoothly switch from the control channel to the call channel.

[0011]

However, the above-mentioned conventional portable telephone has the following problems. Firstly, there was a problem that wasteful power consumption was spent in the PLLAMP 27. Specifically, TD
In the MA method, the actual transmission / reception timing is only the control time slot (intermittent transmission) that appears periodically in the control channel, and only the assigned time slot in the speech channel. Nevertheless, since the PLL AMP 27 is always supplied with power, wasteful power consumption occurs.

Secondly, there is a problem that the secondary emission level from the antenna is not improved. Specifically, since the amount of the electric field injected from the VCO 21 to the fixed attenuation circuit 26 is not controlled even when the received electric field strength level is medium and the electric field is strong,
There was a problem that the secondary emission level was not improved due to the leakage in the mixer 35 and the incomplete isolation when the circuit portion was duplicated. Here, the leak means that a frequency component other than a desired frequency leaks and is output from the mixer 35, and the isolation means that the output of one PLLAMP and the other PLLA when the circuit portion is duplicated.
It means separating from the output of MP. As a result, the secondary emission level of the frequency component (spurious) other than the desired frequency in the case of the antenna at the time of transmission and the frequency component of the other PLL circuit portion at the time of the reception may exceed the allowable range.

In view of the above points, it is an object of the present invention to provide a portable telephone which has reduced power consumption, reduced spurious during transmission, and low secondary emission level during reception.

[0014]

In order to solve the above-mentioned problems, the invention of claim 1 is a TDMA type mobile phone, wherein a transmitter mixer for converting a modulated signal into a transmission frequency,
A receiving-side mixer that converts a reception frequency to an intermediate frequency; a first PLL circuit that outputs a local signal of a first frequency;
A second PLL circuit that outputs a local signal of a second frequency and a first PLL circuit that attenuates the local signal from the first PLL circuit.
Variable attenuator, a second variable attenuator for attenuating the local signal from the second PLL circuit, and the output of the first variable attenuator are amplified and output to the transmitter-side mixer and the receiver-side mixer. A second amplifier that amplifies the output of the first amplifier and the second variable attenuator and outputs the amplified output to the transmitter-side mixer and the receiver-side mixer, and the first variable attenuator and the second amplifier according to the received electric field strength. Gain control circuit that changes the attenuation value of each variable attenuator of
A power supply control circuit that controls the power supply to the first amplifier and the power supply to the second amplifier according to the transmission / reception timing is provided.

According to a second aspect of the present invention, in the portable telephone set according to the first aspect, the gain control circuit indicates the received electric field strength R.
When the SSI (Recieving Signal Strength Indicator) signal indicates a strong electric field, the first variable attenuator and the second variable attenuator
Is configured to reduce the gain of the variable attenuator. According to a third aspect of the present invention, in the mobile phone according to the first or second aspect, the power supply control circuit includes a first power supply circuit that supplies power to the first amplifier and a second power supply circuit that supplies power to the second amplifier. The operation of the first power supply circuit is stopped except for the transmission timing and the reception timing of the second power supply circuit and the first PLL circuit, and the second power supply is provided except for the transmission timing and the reception timing of the second PLL circuit. And a control circuit for stopping the operation of the circuit.

[0016]

With the above means, in the portable telephone according to the first aspect of the invention, the gain control circuit varies the attenuation value of each of the first variable attenuator and the second variable attenuator according to the received electric field strength. . As a result, the gains of the first and second variable attenuators are adjusted, so that the leakage at the transmitting side mixer and the receiving side mixer at the subsequent stage is reduced, and the first PLL circuit and the second PLL circuit are also reduced. The isolation with is improved.
In addition, the power supply control circuit sets the first
Since the power supply to the amplifier and the power supply to the second amplifier are controlled, the power consumption in the first and second amplifiers does not occur except at the transmission / reception timings thereof.

According to a second aspect of the present invention, in the portable telephone set according to the first aspect, the gain control circuit indicates an RSSI (Recieving Signal Strengt) indicating a received electric field strength.
When the h Indicator) signal indicates a strong electric field, the gains of the first variable attenuator and the second variable attenuator are reduced. In the mobile phone according to the invention of claim 3, in the mobile phone according to claim 1 or 2, the control circuit is the first PL.
The operation of the first power supply circuit is stopped except for the transmission timing and the reception timing by the L circuit, and the second PLL
Only the transmission timing and the reception timing by the circuit are second
The power supply circuit of is stopped. As a result, power consumption does not occur in the first amplifier and the second amplifier other than the above transmission / reception timing.

[0018]

1 is a block diagram showing the configuration of a mobile phone according to an embodiment of the present invention. In this mobile phone, bidirectional communication by the TDMA method is performed by using carrier waves of the same frequency for both transmission and reception. In the figure,
The upper part shows a receiving circuit, the middle part shows a transmission / reception common circuit, and the lower part shows a transmitting circuit. The same reference numerals are given to the same constituent elements as in FIG.
The partial circuits around the LL (PLLA, PLLB in the figure) show a duplicated example. Hereinafter, the same parts as the conventional one will not be described, and different parts will be mainly described.

The difference from FIG. 1 is that the variable attenuation circuit 101 is provided.
a, variable attenuation circuit 101b, PLLAMP 102a, P
LLAMP 102b, power supply circuit 103a, power supply circuit 103b, SW circuit 104, variable AMP control circuit 1
05, the power control circuit 106 is provided. The variable attenuator circuit 101a is an attenuator circuit for gain adjustment that attenuates the output of the PLLA circuit, and the variable AMP control circuit 10a.
In accordance with the control signal (CON1, CON2, SYNA / B) from 5, the gain has three levels (high, middle, low).

The variable attenuating circuit 101b is a gain adjusting attenuating circuit for attenuating the output of the PLLb circuit.
Control signals from the MP control circuit 105 (CON1, CON2, SYNA /
Depending on B), it has three levels of gain (high, middle and low). The variable attenuation circuits 101a and 101b are, for example, 3 bit GaAs Digital At such as AT-230 manufactured by Meicom.
Tenuator etc. can be used, and the ATT value is variable AM
Control signal from P control circuit 105 (CON1, CON2, SYNA / B)
It is controlled arbitrarily by.

The PLLAMP 102a is an amplifier for attenuating the output of the variable attenuating circuit 101a in order to match the input levels to the mixer 35 and the mixer 7 in the subsequent stage and to match with the PLLA circuit. It operates only when power is supplied from the power supply circuit 103a. PLLAMP 102b
Is an amplifier for attenuating the output of the variable attenuator circuit 101b in order to match the input levels to the mixers 35 and 7 in the subsequent stage and to achieve matching with the PLLA circuit. It operates only when power is supplied from the power supply circuit 103b.

The power supply circuits 103a and 103b are controlled by the variable AMP control circuit 105, and each of them is a PLL.
Power is supplied to the AMP 102a and the PLL AMP 102b. For example, if a regulator power supply IC such as the TK11XXX (Toko Co., Ltd.) series is used, power is supplied when pin 1 (control terminal) is at a high level and power is not supplied when it is at a low level. This control terminal is variable AM
It is controlled by the P control circuit 105.

The SW circuit 104 is a variable AMP control circuit 1.
The output of the PLLAMP 102a and the PLL by the control of 05.
The output of the AMP 102b is switched and output to the mixer 35 or the mixer 7. The variable AMP control circuit 105
Various control signals (T / R, TXON, RXON, SYNA from control device 20)
/ B, CON1, CON2), the gains of the variable attenuation circuits 101a and 101b are controlled. Specifically, FIG. 2 shows a time slot arrangement showing the relationship between various control signals and gains and their timing. In the "slot arrangement" part at the top of the figure, "CS" is the base station (base unit)
“PSA” indicates the operation by the PLLA circuit of the mobile phone, and “PSB” indicates the operation by the PLLB circuit of the mobile phone. "I" in the slot indicates an idle time slot, "Ri" indicates a receiving operation, and "Ti".
Indicates a transmission operation corresponding to “Ri”. “Control signal” at the bottom of the figure shows the timing (SYNA / B, RXON, TXON, T / R,) of various control signals output from the control device 20. SYNA /
B is a signal indicating which of the PLLA circuit and the PLLB circuit is used, TXON indicates a transmission timing, RXON indicates a reception timing, and T / R is a signal indicating transmission or reception. The middle part shows the combination of (CON1, CON2) of "at high gain", "at middle gain" and "at low gain" and its output timing. As shown in the figure, (CON
The combination of (1, CON2) is (high, high) for high gain (low, high) for middle gain (high, low) for low gain variable attenuation circuit 101a and variable attenuation circuit 101
This is a signal for instructing b, and the middle gain and the low gain indicate different gains during reception and during transmission. CO
N1 and CON2 are signals based on the RSSI signal. When the received electric field strength is weak (high, high), when it is strong (high, low), in the middle, (low, high).
become.

The power supply control circuit 106, based on various control signals (T / R, TXON, RXON, SYNA / B) from the control device 20,
The power supply of the power supply circuit 103a and the power supply circuit 103b is controlled. Specifically, FIG. 3 shows a slot arrangement showing control signals and their timings. In the figure, "ON_A" is a control signal for the power supply circuit 103a, which instructs the power supply at a high level and the power supply stop at a low level. “ON_B” is a control signal for the power supply circuit 103b and is similar to ON_A. As shown in the figure, the power supply control circuit 106 controls so that power is supplied only at the timing required for transmission and reception.

The operation of the portable telephone device of the present invention configured as described above will be described below. The PLLA circuit and the subsequent circuit are referred to as the A circuit, and the PLLB circuit and the subsequent circuit are referred to as the B circuit. Switching between the A circuit and the B circuit is controlled by the control device 20. At that time, the variable AMP control circuit 105 controls the control signal (CON
1, CON2), the attenuation values (gains) of the variable attenuation circuits 101a and 101b are adjusted as shown in FIG. Now, assuming that it is the transmission / reception timing using the A circuit, the attenuation values of the A circuit and the B circuit are set as follows, for example. A circuit B circuit CON1 CON2 GAIN SYNA / B gain CON1 CON2 GAIN SYNA / B gain HH HIGH A 0dB HH HIGH A -28dB LH MID A -4dB LH MID A -28dB HL LOW A -4dB HL LOW A -28dB The opposite occurs in the transmission / reception timing used. By adjusting the attenuation values of the variable attenuation circuits 101a and 101b in this way, the local injection value from the PLL circuit to the mixer 7 and the mixer 35 can be reduced. As a result, the leak amount in the mixer can be reduced. Further, by increasing the attenuation value of the variable attenuation circuit after the unused PLL circuit, the isolation from the other PLL circuit is improved and the leak value in the mixer is further reduced.

Further, the power supply control circuit 106 receives the power supply circuit 103 by the control signals (ON_A, ON_B) shown in FIG.
a and the power supply circuit 103b are controlled so that power is supplied only at the transmission timing and the reception timing.
As a result, low power consumption can be achieved.

[0027]

As described above, according to the first aspect of the present invention, the gains of the first and second variable attenuators are adjusted, so that the leakage to the transmitting-side mixer and the receiving-side mixer in the subsequent stage is achieved. Is reduced, and the isolation between the first PLL circuit and the second PLL circuit is improved. As a result, spurious is reduced at the time of transmission, and the secondary emission level is reduced at the time of reception. Further, the power supply control circuit supplies power to the first amplifier and the second power supply according to the transmission / reception timing.
Since the power supply to the amplifier is controlled, the power consumption in the first and second amplifiers is not generated at timings other than the transmission / reception timings, so that there is an effect of reducing the power consumption.

According to the invention of claim 2, there is the same effect as that of claim 1, and RSSI (Reci
The gain of the first variable attenuator and the second variable attenuator can be controlled by the eving Signal Strength Indicator) signal. According to the invention of claim 3, in addition to the effect of claim 1 or 2, the operation of the first power supply circuit is stopped except for the transmission timing and the reception timing by the first PLL circuit, and the second PLL circuit. The operation of the second power supply circuit is stopped only at the transmission timing and the reception timing. As a result, there is an effect that power consumption does not occur in the first amplifier and the second amplifier other than the transmission / reception timing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a mobile phone according to an embodiment of the present invention.

FIG. 2 is a time chart showing a time slot arrangement showing a relationship between various control signals and gains and their timings.

FIG. 3 is a time chart showing timings of various control signals and power supply control, and slot arrangement.

FIG. 4 is a block diagram showing a configuration of a mobile phone according to a conventional technique.

[Explanation of symbols]

 1 Antenna 2 Transmission / Reception Filter 3 Antenna Switch 101a Variable Attenuation Circuit 101b Variable Attenuation Circuit 102a PLLAMP 102b PLLAMP 103a Power Supply Circuit 103b Power Supply Circuit 104 SW Circuit 105 Variable AMP Control Circuit 106 Power Supply Control Circuit

Claims (3)

[Claims] 1. A TDMA-type mobile phone, comprising a transmitter mixer for converting a modulated signal into a transmission frequency, a receiver mixer for converting a reception frequency into an intermediate frequency, and a local signal of a first frequency. A first PLL circuit for outputting, a second PLL circuit for outputting a local signal of a second frequency, a first variable attenuator for attenuating the local signal from the first PLL circuit, and a second PLL A second variable attenuator that attenuates a local signal from the circuit; a first amplifier that amplifies the output of the first variable attenuator and outputs the amplified output to the transmitter-side mixer and the receiver-side mixer; Amplifier for amplifying the output of the mixer and outputting it to the mixer on the transmitting side and the mixer on the receiving side, and the attenuation values of the first variable attenuator and the second variable attenuator are changed according to the received electric field strength. To control the gain control circuit and the transmission / reception timing. Flip and first mobile phone, characterized in that a power control circuit for controlling the power supply to the power supply and the second amplifier to the amplifier. 2. The gain control circuit comprises an RSSI (Recieving Signal Stren) indicating a received electric field strength.
gth Indicator) 1st when the signal indicates a strong electric field
2. The mobile phone according to claim 1, wherein the gains of the variable attenuator and the second variable attenuator are reduced. 3. The power supply control circuit includes a first power supply circuit that supplies power to a first amplifier, a second power supply circuit that supplies power to a second amplifier, and a first PLL circuit. And a control circuit for stopping the operation of the first power supply circuit except for the transmission timing and the reception timing by the second PLL circuit and stopping the operation of the second power supply circuit for the second PLL circuit except the transmission timing and the reception timing. The mobile phone according to claim 1 or 2, characterized in that: