JPS59212035A - Transmission output controlling circuit - Google Patents

Abstract

PURPOSE:To transmit an output which is almost constant regardless of an in- use channel over a wide frequency range by setting automatically such an APC reference voltage that the transmission output is within a specific error range simultaneously with chennel setting. CONSTITUTION:A control voltage EC for tracking a transmission/reception frequency to a desired value is applied to level comparators 90A, 90B, 90C, and 90D. When a channel 1 is set, the voltage EC is low, so the comparators 90A- 90D are in operation and their output terminals (a) are all grounded. Therefore, base voltages of the transistor (TR) T1 of an output adjustment part 8 is low. Then when a channel 4 is set, the terminal (a) of the comparator 90A is released, so the base voltage of the TRT1 is slightly higher. Thus, the base voltage of the TRT1 is made higher and higher as the channel is higher and higher, and an almost constant output is transmitted regardless of an in-use channel.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmission output control circuit that uses a directional coupler to extract a traveling wave component of a transmission output and feed it back to the previous stage to output a constant transmission output. It is related to.

1. Configuration of conventional example and its problems FIG. 1 is a block diagram of a transmitter using a conventional transmission output control circuit. Reference numeral 1 is an oscillation unit, and when a large number of channels are used, a frequency synthesizer is used. 2 is a channel switcher, and in the case of a system in which a channel is specified from a base station that sends out channel information and frequency tracking information that determine the output frequency of the synthesizer, the channel switcher 2 is a converter for converting the specified signal and channel information, etc. is used. 3 is a pre-stage section that performs necessary multiplication, mixing, amplification, etc. depending on the communication method used, and θ4 is a power amplification section configured to output a desired frequency to a terminal 41; 41 is an input terminal; 42 is an output terminal, and 43 is an output control terminal. 6 is a directional coupler, 51 is an input terminal, 52 is an output terminal, and 53 is a traveling wave detection output terminal. 6 is a low-pass filter (LPF) that removes harmonic components of the transmission output; 0 is the transmission output terminal; and 8 is a transmission output adjustment section, which adjusts the height of the transmission output according to information from the detection output terminal 63 to the input terminal 81. It constitutes an automatic transmission power control (APC) circuit that knows this, sends a control voltage to the power amplification section 4, and adjusts the transmission output to a constant value. The transmission output adjustment section 8 has a built-in regulator for manually adjusting the reference voltage. This is fixed after the transmission power is set to a predetermined value. 10 is a microphone.

In such a configuration, the output of the detection output terminal 53 of the directional coupler 6 has frequency characteristics, and the output tends to increase as the frequency becomes higher. Using this output,
If C is performed, the high frequency output will be reduced. This tendency is particularly noticeable in the case of multi-channel switching and wideband, and for this reason, some kind of countermeasure has been required to reduce output fluctuations caused by channel switching.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks and to provide a transmission output control circuit that can transmit a constant output within a wide frequency band regardless of the frequency (channel) used. Structure of the Invention In order to achieve the above-mentioned object, the present invention attempts to improve transmission output fluctuations depending on the channels used by automatically setting an APC reference voltage such that the transmission output falls within a certain error range at the same time as channel setting. It is something to do.

DESCRIPTION OF EMBODIMENTS The configuration and operation of an embodiment of the present invention will be described below. FIG. 2 is a block diagram of a transmitter that employs the transmission output control circuit of the present invention. In the figure, 1 is an oscillator, 2
is a channel switcher, 3 is a front stage section that performs transmission, mixing, amplification, etc., 4 is a power amplification section, 6 is a directional coupler, and 6 is an LPF.
, 7 are output terminals, which have the same functions as those with the same numbers in FIG. Reference numeral 8 denotes an output adjustment section for transmitting output, which compares the output of the directional coupler with a reference voltage and outputs the result to the power amplification section 4 . 81 is an input terminal for traveling wave information of the directional coupler 5, 82 is a control output terminal to the power amplifier section, 83 is an input terminal for a reference voltage, and 9 is an automatic transmission power control (APC) circuit O reference voltage generation section. Yes, it is converted from the channel control information from the channel switch 2.

When receiving channel designation from the base station, replace the channel designation signal with one that converts it into channel control information 51
· available. The output control unit 8 further detects the environmental temperature, corrects the control voltage, and forms a reference voltage that is compatible with both the channel and the environmental temperature. This output is added to the power amplifying section 4 to form a control loop to obtain a stable transmission output with respect to the channel used and the environmental temperature.

FIG. 3 is a circuit diagram showing an embodiment of the transmission output control circuit of the present invention, in which 43 is a control input terminal of the power amplifying section 4;
denotes a traveling wave detection output terminal of the directional coupler 6, a voltage regulator 80, and transistors T1. T2. The base voltage K (1) of the transistor T2 of the voltage comparator composed of T5 is changed. 85, 86° 87 is a resistor, 88 is a thermistor that detects the environmental temperature, and the voltage that corrects the temperature characteristics of the PC loop is adjusted. The reference voltage controller 9 is supplied to the base of the transistor T1.The reference voltage controller 9 uses the reference voltage 1!:f of the output controller 8 according to the tracking information of the channel switch 2, and controls the channel in a stepwise manner. 93 is an input terminal of a constant voltage power supply, 90A is a switch circuit that grounds resistor 6 to ground resistor 971L when the trunking information IC is lower than the reference voltage He of 9OA, and 96 is a voltage comparison IC, which is an operational terminal. An amplifier is used. 94 and 95 are voltage dividing resistors that set the reference voltage Ee, and 90
A, 90B, 90G, and 90D have different operation levels.

Next, the operation of the above configuration will be explained using FIGS. 3 and 4. FIG. 4 is a control voltage for channeling, and changes as shown in the IC in FIG. 4 (m) in response to channel switching. This voltage Ec is applied to the Lebel comparators 90A and 90B in FIG.

Applied to each terminal A of 90C and 90D, voltage comparison l09
6 (7) each (→ added to the terminal (90B, 90C.

Internal elements inside 90D are omitted). Terminal 93 has a constant voltage as mentioned above! b has been added.

This voltage is applied to each terminal (b) of the voltage comparators 90A to 90D, and is divided by a voltage dividing resistor corresponding to the voltage dividing resistor 94.95 of the voltage comparator 90A. A comparison voltage 1e7 ・”- is applied to the (→ terminal of C96. In this Ec main voltage voltage comparator 90A, Ee+
and in 90B, lCe2. Similarly, Be4 is used for 90D. The tracking voltage Ea changes as shown in FIG. 4(A) as the wireless channel is switched. Tracking voltage EcF for channel 1
Since it is lower than iEe+, Be52, Be5, Be34, the voltage comparator 90A, 90B, 900°90D
is in the operating state, and the output terminals C of 901 to 90D are all grounded. Therefore, since the resistors 97a to 97d are connected in parallel to the base of the transistor T1, the fourth
As shown in the diagram (B), the voltage Ef is as low as Efo. When it comes to channel 4, gc:>Eel, the terminal C of the voltage comparator 90A is opened, and the resistors 97b and 9
70.97d only.

Then, the pace voltage of the transistor T1 is tossed to Ef+.

Next, when 10>)Ce2 is reached, the output terminal C of the voltage comparator 97b becomes open, and the base voltage of the transistor T1 becomes E.
Let it be f2. Similarly, when EC>EC5, to Ef3,
When Kc>EC4, the base voltage becomes Ef'4. Transistors Tl, T2 . The circuit consisting of T3 is a traveling wave detection output! This is an output controller in which d is a reference voltage Σf, transistors T1 and T2 are comparators, and transistor T5 is a controller. Here, the reference voltage Kfo
and Efl, the transmission output PO becomes the reference output Pg in channels 2 and 4, as shown in FIG. 4(C). However, in the channels before and after this, the output varies by the maximum weight Δ with respect to the reference output Ps, but since the value of Δ is about 2 to 4 percent of the reference output Pg, there is no problem. Figure 4 (B
) shows the relationship between the channel number and the reference voltage Ef, as shown in Figure 4 (Q
indicates the relationship between the channel number and the reference transmission output Ps. In addition, the voltage comparator should be stabilized by giving hysteresis in order to prevent fluctuations due to minute changes in Ec at the operating point, or the switching point of the pace voltage Ef of the transistor T1 of the output adjustment section 8 should be set at the channel. It is best to avoid hitting the voltage point corresponding to the number.

By setting the voltage as described above, it is possible to suppress fluctuations to the maximum weight Δ with respect to the reference transmission output Ps. Moreover, this variation Δ can be about several tenths of the reference transmission output Ps9/−. Note that in the above explanation, the power amplification section 4 of the transmitter is controlled from the output adjustment section 8, but the power amplification section is composed of a power amplifier and an excitation section, and the collector current of the excitation section is Since the excitation output is changed by control, it can be used in the same way even if it is not modularized.

Effects of the Invention The present invention has the above-described configuration, and provides the following effects.

(1L) Even if the characteristics of the frequency tracking voltage change in a complex manner within the used channel, the change in the transmission output is simple, so setting the reference level is easy.

(b) By increasing or decreasing the number of determination points depending on the degree of allowable output fluctuation value and the difficulty of the standard, it is possible to adapt to the required characteristics.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional radio device with a transmission output control circuit, FIG. 2 is a block diagram of a radio device that employs the transmission output control circuit of the present invention at 10ti-”, and FIG. 3 is an embodiment of the present invention. 4 is a circuit diagram of a transmission output control circuit in FIG. ...Reference voltage generation section, 90A to 90D...Voltage comparator, T
1. T2, T3...Transistor, 85,8
6, 87, 88...Resistor and thermistor,
971L to 97d... Resistors for changing the reference voltage.

Claims (1)

[Claims] Used in multi-channel switching transmitters, an automatic output control loop is formed by a power amplification module, a directional coupler that detects traveling wave components, and an output control section, and the control reference voltage of the output control section is controlled by a circuit tracking voltage. A transmission output control circuit characterized in that a reference voltage change control circuit is used to set a stepped voltage for a used channel.