JPH02181525A - Temperature compensation type gain setting control device - Google Patents

Abstract

PURPOSE:To execute stable gain setting and temperature compensation by one variable attenuator by determining the attenuation quantity of the variable attenuator necessary for the setting of gain, preparing a bias value for obtaining a value obtained by adding/subtracting a temperature compensation value to/ from the attenuation quantity by a ROM and D/A converting the bias value. CONSTITUTION:Potential 10 is changed in accordance with a change in temperature. The potential is converted into digital temperature information by comparators 11 constituted of multistages having respectively different threshold values. On the other hand, a telecommand signal 2 is applied to a telecommand input terminal 1, the gain set point of a repeater is decoded by a gain status decoder 7 and the decoded value is inputted to the ROM 12. The upper address and lower address of a ROM address are respectively distributed to gain setting and temperature compensation, and bias values for obtaining the attenuation quantity of the variable attenuator 5 corresponding to respective addresses are read out. The read digital bias values 14 are converted into an analog voltage by a D/A converter 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention allows the gain of a repeater constructed from a microwave circuit to be varied in fixed steps by an external command, and also to prevent gain displacement due to temperature fluctuations. The present invention relates to a compensated gain control device.

[Conventional technology]

Conventionally, there has been a device of this type as shown in the block diagram of FIG. (1) is a teleconverter 1 signal input terminal,
(2) is a telecommand signal, (51Fi attenuator whose attenuation amount can be varied depending on the applied bias value, (6
1 is an amplifier that amplifies the RF flaw signal, ■ is a temperature compensation circuit, ■
is the gain control circuit, (51) is the bias value that sets the attenuation amount of the variable attenuator that corrects the gain fluctuation of the repeater due to temperature fluctuation, and (52) is the attenuation amount of the variable attenuator when changing the repeater gain. Indicates the bias value to set.

FIG. 4 shows details of the temperature compensation control circuit. (8) is a thermistor, (9) is a resistor, and Cl111 is an operational amplifier.

FIG. 5 shows details of the Fi gain control circuit. (7) is a gain status decoder, Gυ is gain status information, (
(to) is the bit-bang conversion circuit, (to) is the selected switch information, (@) is the analog switch, (to) is the variable attenuator necessary to obtain the set repeater gain (51 bias values, the number of which is the gain range) is determined by the number of steps. (to) indicates a switch group. Figure 6 shows the details of the analog switch @.
141+, tQ indicates a resistor.

FIG. 7 shows the applied bias (5) of the variable attenuator (5).
1 and 52) shows the relationship between voltage and attenuation amount.

When the bias voltage exceeds the value, the amount of attenuation reaches a ceiling.

FIG. 8 shows any output bit pattern of the gain status decoder (7). When a straight binary code is used, the binary value and the attenuation amount match.

FIG. 9 [al shows the output bit 83 of the bit conversion circuit (to). The number of bits required is equal to the number of steps n.

Next, the operation will be explained. Due to temperature fluctuations, the potential at the connection point between the thermistor (81) and resistor (9) changes.

The offset voltage of operational amplifier +211 is controlled. As a result, the output potential (51) of the operational amplifier.

The bias potential of the variable attenuator +51 changes in proportion to the temperature gradient of the thermistor, and controls the amount of attenuation of the variable attenuator. Next, when changing the intermediate gain, a telecommand signal is applied to the telecommand signal input terminal (11).The gain status decoder (7) decodes the new set gain, and the straight binary code gain status fff@ on is output.The gain status information is applied to the bit-bang conversion circuit (to), converted to n-bit selection switch information (to), and output.The analog switch [with] outputs the stabilized voltage source un. The resistors 1411 and 143 are divided by changing the combination to obtain n bias voltages corresponding to the required n settings and flJ gain.Each input port of the switch group (to) has one selection switch information. There is a one-to-one correspondence with each bit (to), and the input port and output port corresponding to the enable bit are in a conductive state.At this time, the voltage value obtained by dividing the stabilized voltage source output by resistance is directly applied as a bias voltage (52) to another variable attenuator (81), changing the passage loss of the variable attenuator and changing the repeater gain to the set value.

[Problem to be solved by the invention]

Since the conventional gain temperature compensator and gain control device are configured as described above, it is necessary to improve the accuracy of the amount of change of the variable attenuator, and it is necessary to increase the setting accuracy of the applied bias value. In addition, compensation for the temperature drift of the operational amplifier must be included, and the cut pattern is converted once in order to change the analog switch, so if a large surplus setting range is required, , it is necessary to prepare many setting bias values,
As a result, the scale of the hardware for analog switches and bit-bang conversion circuits has increased, and there are problems such as the limited number of combinations of dividing resistors, even though the accuracy of each set bias value is required.9

This invention was made to solve the above-mentioned problems, and it is possible to improve the precision of the bias value applied to the variable attenuator and eliminate the need for hardware for converting bit beats.

The aim is to eliminate the need for compensation of the temperature compensation circuit itself and to obtain a device in which the hardware configuration does not need to be changed at all even if a large repeater gain range is required.

[Means for solving Lesson 1] A temperature compensated gain setting control device according to the present invention.

Temperature compensation and residual gain settings are shared by one variable attenuator, and the bias value to be applied is a digital value that is a combination of temperature information and gain setting information, which is stored in ROM (IJ-only memory), and the temperature status and , the value extracted from vt is converted into an analog value by the iD/A converter as the gain status gold address.

[Effect]

The temperature compensated gain setting control device of the present invention determines the amount of attenuation of the variable attenuator necessary for sternum setting, and sets the bias value iRO to a value obtained by increasing or decreasing the value of the temperature compensation valve to this value.
Since the voltage is obtained by D/A conversion, a highly accurate voltage value can be obtained, and stable gain setting and temperature compensation can be performed with a single variable attenuator.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, fi+, +21. +51. (6) is exactly the same as the conventional device. (3) is a gain temperature compensation circuit.

(4) is the applied bias of the variable attenuator, and (3
The details of 1 are shown in Fig. 2.

In the figure, (71, +81. +91Fi is exactly the same as the conventional circuit. α1 is a partial pressure value that changes with temperature fluctuations, al is a multi-stage comparator, (IX5
is ROM.

0 is the ROM address input, (141 is the output that digitizes the bias value applied to the variable attenuator.

a indicates a D/A converter.

FIG. 9 fbl shows the ROM address.

Next, the operation will be explained. As the temperature fluctuates, the resistance value of the thermistor (81) changes, and the potential αG at the connection point with the resistor (9) also changes. This potential is converted into digital temperature information by a multi-stage comparator αυ with different threshold values. Completely independently of this, a telecommand signal (2) is applied to the telecommand input terminal (1), the gain status decoder (7) decodes the gain setting value of the repeater, and the temperature information at this time and ROMfi2 in the t13
is input to. As for the ROM address, the upper address is divided into gain setting, the lower address is divided into temperature compensation, and the bias value for obtaining the attenuation amount of the variable attenuator corresponding to each address is read out.

The read digital bias I is converted into an analog voltage by a D/A converter cIs. The accuracy of the analog value converted at this time is determined by the input bits and dynamic range of the D/A converter.

- For example, D with 8 bit input and 5 V dynamic range.
Assuming a /A converter, every time the address changes by 1 (2).

The bias value of the variable attenuator can be controlled with an accuracy of 0.02 (V) in 5/28. The bias voltage output from the D/A converter (41) is applied to the variable attenuator (51) to vary the amount of attenuation and adjust the overall gain of the repeater.

Compensates for gain changes due to temperature fluctuations.

〔Effect of the invention〕

As described above, according to the present invention, the ROM address that determines the bias value of the variable attenuator.

Since the gain setting information and temperature information are used together, only one variable attenuator is required, and there is an effect that highly accurate gain setting and temperature compensation can be obtained.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing a temperature compensated gain setting control device according to an embodiment of the present invention, FIG. 3 is a diagram showing a conventional system, and FIG. 4 is a diagram showing the entire conventional temperature compensation circuit. ,
FIG. 5 is a diagram showing a conventional gain setting circuit, FIG. 6 is a diagram showing details of the analog switch in FIG. FIG. 8 is a diagram showing the cut pattern of the gain status information, 9th [1W (al is a diagram showing the bit pattern of the selection switch information in FIG. 5, and FIG. 9 Tbl is a diagram showing the ROM address.) lld telecommand signal input terminal, (2) is telecommand signal, (3) is gain status decoder, +81
ij thermistor, (91 is a resistor, an is a temperature fluctuation potential, al is a multi-stage comparator with different threshold values, fi3 is a ROM, +13 is a ROM7 decoder L//C
, aa are digital bias values, (19 is a D/A converter, and (41ij is a bias value applied to the variable attenuator (5).

Claims (1)

[Claims] It has an input terminal into which telecommand pulses are input, a gain status decoder that decodes the set gain status from the input command signal, and the potential at the connection point of the resistor and sursistor connected in series between the power supply and ground. The RO has a multi-stage comparator arranged in parallel, uses these output signals as an address, and reads out the voltage value necessary to obtain the attenuation amount corresponding to the gain setting value suitable for the ambient temperature environment.
M (read-only memory), a D/A converter for converting the value output from the ROM into an analog quantity, and a variable attenuator that can control the passing loss using the analog voltage value converted by the D/A converter. A temperature compensated gain setting control device characterized by being configured in this order.