JPH07131414A - Apc circuit for burst transmission signal - Google Patents

Abstract

PURPOSE:To reduce the circuit scale of the APC circuit for burst transmission signal where the output of the differential amplifying circuit, which takes a reference voltage for comparison as one input and obtains the detection voltage of a transmission output wave as the other input and obtains the difference between them, is used as the control signal of transmission output so that the output of the transmission power amplifier which performs power amplification of the burst signal transmitted at a certain timing has a prescribed transmission power in the transmission part of a digital portable telephone terminal machine or the like. CONSTITUTION:A certain DC voltage Vr showing the reference output value of transmission output is taken as the reference voltage of one input of a differential amplifying circuit 5, and a DC offset voltage Voff showing the set value of transmission output is added.o a transmission output wave, and a detected detection output voltage V(t) is sampled by a timing control signal 4 generated from the burst transmission signal, and the output of a sampling and holding circuit 3 which holds the sampled output is taken as the signal of the other input of the circuit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting section of a digital mobile phone terminal or the like, and more particularly, to automatically setting an output of a transmission power amplifier of a burst signal transmitted by the transmitting section at a constant timing to a predetermined power. A of burst transmission signal to control
Regarding the PC circuit. As for the APC circuit for the burst transmission signal of the digital mobile phone terminal, it is desired that the circuit scale thereof be as small as possible to contribute to downsizing of the entire terminal device.

[0002]

2. Description of the Related Art FIG. 6 shows the structure of a conventional APC circuit for a burst transmission signal of a digital portable telephone terminal. In the figure,
Reference numeral (14) is an envelope generation circuit, which generates a signal representing the envelope of the burst transmission signal which is the reference input voltage of one input (-) of the differential amplifier circuit (5). The detailed operation is shown in FIG.
(a) As shown in the configuration diagram, the ROM of the squared values I ² and Q ² is read by the input transmission signals I and Q (t), and the added value (I ² + Q ² ) is added by the adder.
And read √ (I ² + Q ² ) from the √-valued ROM via FF. Then, in the multiplier, in order to suppress the spread of the spectrum due to the harmonic generation at the rising and falling (ramp) of the burst transmission wave, it rises from the binary burst signal at a fixed timing (for example, 42 kHz cycle) from the outside. Then, the ramp that is the fall time is generated, the time is determined by the counter, the Hanning window function is read from the ROM of the Hanning window, and is multiplied by √ (I ² + Q ² ). Then, after the multiplication output is D / A converted, it is passed through the low pass filter LPF and
As shown in (b) Waveform diagram, the envelope (about 2kHz cycle)
Generate the signal. 6 (15) is an offset voltage generating circuit, the output of which is finally input to the other input (+) of the differential amplifier circuit 5 and is not shown in the figure. The output of each specified value (for example, -0 dB to -20 d
The control signal c set in B) is obtained, and a DC offset voltage Voff to be added to the input side and the output side of the detection output detection diode (2) is generated in advance. (2) is a detector diode, which cuts the direct current of the output wave of the transmission power amplifier 10 with the capacitor C, and outputs the direct current offset voltage Voff of the offset voltage generation circuit 15.
Is added to the input side of the diode (2) via a resistor R7 and to the output side via a low pass filter R3, C1 with a cut-off frequency fc of about 2 kHz, and then the transmitted output wave is detected. It outputs a DC voltage signal V (t) that changes with time and represents the magnitude of the transmission power. (5) is a differential amplifier circuit, the envelope generation circuit
The envelope signal of the output of 14 as the reference input voltage of one input (-), the other input (+) as the DC voltage signal V (t) detected by the detection diode (2), the difference between them. And output. Then, the difference output thereof becomes the control signal c of the transmission output, and controls the variable attenuator 9 of the input stage so that the output of the transmission power amplifier 10 (not shown) has a predetermined power value. That is, in the conventional APC circuit for the burst transmission signal of the digital mobile phone, the reference input voltage of one input (-) of the differential amplifier circuit (5) which generates the control signal c of the transmission output is The low-frequency (2kHz cycle) envelope signal of the burst transmission signal, which has been processed by the burst signal at the constant timing (42kHz cycle) output from the envelope generator (14), is passed through the low pass filter LPF. It was a circuit configuration.

[0003]

As described above, the APC circuit for the burst transmission signal of the conventional digital portable telephone terminal has one input of the differential amplifier circuit (5) for generating the transmission output control signal c thereof. Since the reference input voltage of (-) uses the envelope signal generated by the envelope generating circuit 14 having a large circuit scale, the APC circuit is occupied on the printed circuit board on which all the circuits are mounted. There was a problem that the area became too large. It is an object of the present invention to realize an APC circuit that automatically controls an output power of a burst transmission signal by using a differential amplifier circuit with a circuit scale as small as possible.

[0004]

The basic configuration of the present invention for achieving this object is, as shown in the principle diagram of FIG. 1, one of the differential amplifier circuits (5) for generating a control signal c of a transmission output. A constant DC voltage Vr representing the detection voltage of the reference output of the output of the transmission power amplifier 10 not shown in the figure, which is the reference input voltage of the input (-), and the input of the transmission power amplifier 10 at a constant timing. DC offset voltage added to the detection voltage Vr of the reference output to set the amplified output level to a predetermined value when the burst transmission signal is turned on / off
A reference voltage and offset voltage generation circuit (1) that separately outputs Voff, and a direct current cut of the transmission wave of the output of the transmission power amplifier 10 by a capacitor C to reduce the offset voltage Voff to its input side and output side. And a detection diode (2) that outputs a DC voltage signal V (t) that represents the magnitude of the transmission power that changes over time, and a DC voltage signal V (V) output from the detection diode (2). t) is sampled by turning on / off the control signal t for a required time and holding the sample output Vs, and the control signal t is supplied by an external burst signal at a constant timing. A timing control circuit (4) for generating, an output Vs held by the sample hold circuit (3), and a constant voltage Vr corresponding to the reference voltage of the output of the reference voltage and offset voltage generating circuit (1). Input (+) to the differential amplifier circuit (5) , (-) To obtain the difference between them, and the output of the differential amplifier circuit (5) is used as a transmission output control signal c to control, for example, the variable attenuator 9 at the input stage of the transmission power amplifier 10. The transmission output power is automatically controlled to a predetermined value.

[0005]

In the APC circuit of the present invention, referring to FIG. 1, the reference voltage and offset voltage generating circuit (1) detects a constant voltage Vr representing the detection voltage of the reference output of the transmission output and the set output of the transmission output. An offset voltage Voff representing a voltage is separately generated, and the constant voltage Vr is input to one input of the differential amplifier circuit (5).
The offset voltage Voff is input to (-) as a reference input voltage.First, the offset wave Voff is the DC wave cut by the capacitor C of the transmission output wave of the input of the detection diode (2) and the output side of the detection diode (2). And added to the detector diode
(2) detects the input transmission wave and obtains a DC voltage signal V (t) that represents the magnitude of the transmission output that changes with time as the detection voltage and sends it to the sample hold circuit (3). The sample-hold circuit (3) turns ON / OFF the DC voltage signal V (t) from the detection diode 2 by the control signal t of the output of the timing control circuit (4) that receives the burst signal from the outside as the sample. Then, the sample output Vs is held. Then, the held sample output Vs is input as the detection input voltage to the input (+) of the differential amplifier circuit (5). The differential amplifier circuit (5) outputs the detected input voltage, which is the output Vs of the sample-hold circuit (3), and the constant voltage Vr corresponding to the reference voltage of the reference voltage and the output of the offset voltage generating circuit 1. Input each and output the difference between them. Then, the differential output is used as a control signal C of the transmission output to control, for example, the variable attenuator 9 at the input stage of the transmission power amplifier 10 which is not shown in FIG. 1, to automatically set the transmission output power to a predetermined power value. To control. Since the reference voltage and offset voltage generation circuit (1) of the APC circuit of the present invention is a simple DC voltage circuit that separately outputs the constant DC voltage Vr and the offset voltage Voff, which are reference voltages, its circuit scale is small. The sample hold circuit (3) newly provided and the timing control circuit (4) for adjusting the sampling operation to the rising edge of the input detection DC voltage V (t) are also detailed As described above, since the simple configuration is sufficient, the AP of the present invention
The overall configuration of the C circuit is a simple circuit and the purpose is achieved.

[0006]

FIG. 2 is a block diagram of a transmitting section of a digital portable telephone terminal equipped with the APC circuit of the present invention shown in FIG. FIG. 3 shows an embodiment of the APC circuit of the present invention.
Circuit sample and hold circuit (3) and differential amplifier circuit (5)
It is an example arranged in the latter stage. FIG. 4 shows each circuit example of the sample hold circuit and the timing control circuit of the APC circuit of the embodiment of the present invention. In the configuration diagram of FIG. 2, the same components as those shown in the principle diagram of FIG. 1 are represented by the same symbols,
Reference numeral (6), not shown in FIG. 1, is a modulated wave generation circuit, which modulates a radio frequency carrier wave at the timing of transmission data output from the control unit (13) to generate a burst-shaped modulated wave. (7)
Is an amplifier for amplifying the burst-like modulated wave, (8) is a step attenuator for controlling the transmission output power, (9) is a variable attenuator for automatic control of the transmission power, and (10) is a transmission power amplifier. A power amplifier, (11) is a coupling element for branching a part of the transmission power, and (12) is an isolator for impedance matching between the transmission power output circuit and the antenna. The operation of the configuration shown in FIG. 2 is such that a burst modulation wave is generated by the modulation wave generation circuit (6) at the timing of burst transmission data output from the control unit (13), and the burst modulation wave is generated. Modulated wave is amplifier (7), step attenuator
The signal is transmitted from the antenna via (8), the variable attenuator (9), the power amplifier (10), the coupling element (11), and the isolator (12). Here, the variable attenuator (9) varies the level of the input power of the power amplifier (10) by the control signal c of the transmission output output from the differential amplifier circuit (5) of the APC circuit described above. Since the reference voltage and offset voltage generation circuit (1) of the APC circuit is a simple DC circuit that separately outputs the constant DC voltage Vr and the offset voltage Voff, which are reference voltages, as described above, The circuit scale is small. In addition, a newly provided sample hold circuit
(3) and the timing control circuit (4) also receive the burst signal from the control section (13) as the sample hold circuit (3) as shown in (a) Sample hold of the circuit example of the embodiment of FIG. One switch 3 for ON / OFF sampling of the DC voltage signal V (t) output from the detection diode (2) according to the control signal t output from the timing control circuit (4)
1, a simple circuit composed of one charging capacitor 32 for holding the DC voltage signal V (t) when it is ON and one operational amplifier 33 for output. Timing control circuit (4)
As shown in (b) Timing control circuit in the figure,
A shift register 41 which inputs the burst signal from (13) and outputs, for example, 6-bit outputs Q _{0 to} Q ₅ in parallel at _the clock MSK
And the ON / OFF switch control signal t to obtain a pulse signal of a desired time width from the outputs Q _{0 to} Q ₅ of the shift register 41.
As shown in the operation time chart of FIG. 5, for example, output Q ₁ and output Q ₃ are selected and input, and a pulse signal having a time width from the rising edge of Q _{1 to} the falling edge of Q ₃ is output. Do
This is a simple circuit composed of an OR gate 42. According to the embodiments of FIGS. 3 and 4, the APC of the burst transmission signal is performed.
The circuit becomes a circuit having a small circuit scale, a small transmission unit can be realized, and the mobile phone terminal can be miniaturized.

[0007]

As described above, according to the present invention, the APC circuit automatically controlled to set the output power of the burst transmission signal to a predetermined power value is a circuit having a small circuit scale, and the digital portable telephone terminal device. The transmitter can be downsized, and the entire mobile phone terminal can be downsized.

[Brief description of drawings]

FIG. 1 is a principle diagram showing a basic configuration of an APC circuit for burst transmission signals of the present invention.

FIG. 2 is a block diagram of a transmitter of a digital mobile phone terminal equipped with the APC circuit of the present invention.

FIG. 3 is a configuration diagram of an embodiment of an APC circuit of the present invention.

FIG. 4 is a diagram showing each circuit example of a sample hold circuit and a timing control circuit of an APC circuit according to an embodiment of the present invention.

FIG. 5 is a time chart of the operation of the timing control circuit according to the embodiment of the present invention.

FIG. 6 is a block diagram of a conventional APC circuit for burst transmission signals.

FIG. 7 is a diagram of a configuration of an envelope generation circuit of a conventional APC circuit and an operation explanation thereof.

[Explanation of symbols]

(1) Reference voltage and offset voltage generation circuit, (2) Detection diode, (3) Sample and hold circuit, (4) Timing control circuit, (5) Differential amplifier circuit, (9) Variable Attenuator, (10) is a power amplifier that is a transmission power amplifier, Vr is a constant DC voltage as the reference input voltage of the differential amplifier circuit 5, Voff is a DC offset voltage, and V (t) is the detection output of the detection diode 2. A DC voltage signal, Vs is the output of the sample hold circuit 3, c is the output of the differential amplifier circuit 5,
This is the control signal for the transmission output.

Claims (1)

[Claims] 1. A reference voltage for comparison is set to one input (-) in order to set the output of a transmission power amplifier (10) that amplifies a burst signal transmitted at a fixed timing to a predetermined transmission output. ) And the detection voltage of the transmission output wave as the other input (+) to obtain the difference between them and the control signal of the transmission output
(C) In the APC circuit for the burst transmission signal by the differential amplifier circuit (5), one input of the differential amplifier circuit (5)
The reference voltage of (-) is a constant DC voltage (Vr) that represents the detection voltage of the reference output of the transmission output, and the other input (+) is an offset voltage (Voff) that represents the detection voltage of the set output of the transmission output. In addition to the transmission output wave, the detected output voltage is detected by sampling with the timing control signal (4) generated from the burst signal, and the output of the sample hold circuit (3) for holding the sampled output is used. APC circuit for burst transmission signal.