CN104460817A - High-stability power control circuit and method for common-mode temperature compensation demodulation - Google Patents

Abstract

The present invention proposes a highly stable power control circuit for common-mode temperature compensation detection, including: a power modulator, an amplifier circuit, a directional coupler, a wave detector, a power reference generation circuit, and an error summation circuit. The wave detector includes a For the detector tubes, one of the detector tubes extracts the radio frequency output signal, and the other detector tube is set at the reference level output by the power reference generating circuit, and the two detector tubes respectively detect the reference level and the coupled radio frequency signal simultaneously. The detection signal is obtained by common-mode integration of the error summation circuit to obtain the difference, and the output signal of the error summation circuit drives the power modulator. The high-stable power control circuit and method for common-mode temperature compensation detection of the present invention have the characteristics of high power control temperature stability, precise control, simple and easy implementation of the circuit, and low cost.

Description

A high stable power control circuit and method for common-mode temperature compensation detection

technical field

The invention relates to the technical field of testing, in particular to a high-stable power control circuit for common-mode temperature compensation detection, and also relates to a high-stable power control method for common-mode temperature compensation detection.

Background technique

With the development of electronic technology, especially the development and application of new system weapons and equipment, higher requirements are put forward for the signal characteristics of modern signal sources. Taking the high-sensitivity atomic magnetometer system as an example, the atomic magnetic sensor (atomic gas chamber) is the core component unit that constrains the key performance of the system, and requires a high-power RF excitation signal with high stability to meet its infinite discharge and the coordinated and stable work of the entire system It effectively improves the technical ability and overall performance of the system to truly detect/perceive changes in the magnetic field of the external environment, thus creating a high-power and high-stable signal source.

At present, the power control in RF signal generators is generally an automatic level control (ALC) system, and its realization block diagram is shown in Figure 1. The ALC system is mainly composed of a power reference generation circuit, a detection circuit, an error summation circuit, a power modulator, Composed of amplifier circuits, the reference level is generated by the data sent by the CPU in the power reference generation circuit, the detection circuit extracts the size of the RF output signal, and the sum of the current power and the expected error is obtained by comparing with the reference level to adjust the power modulator to achieve power control.

This control system adapts to the power control requirements of radio frequency signal generators, provides a stable and accurate power control method, and has been widely used in various general signal generation power control systems.

In the ALC system shown in Figure 1 above, due to the temperature characteristics of the detector, the voltage of the detector for the same power detection is different at different temperatures, and the detection voltage changes. Through the effect of ALC closed-loop feedback, the output power of the RF signal Changes have also taken place. The change of the output signal power caused by the temperature change of the geophone has seriously affected the stability of the signal output power. This control method has a short-term power stability of more than 5%, which cannot meet the requirements of a high-power stable system. Require.

Contents of the invention

The invention proposes a high-stable power control circuit and method for common-mode temperature compensation detection, which solves the problem in the prior art that the power drift introduced by the temperature characteristics of the detection tube causes the power stability of the radio frequency signal to fail to meet the demand.

Technical scheme of the present invention is realized like this:

A highly stable power control circuit for common-mode temperature compensation detection, including: a power modulator, an amplifier circuit, a directional coupler, a detector, a power reference generation circuit, and an error summation circuit, the detector includes a pair of detector tubes, One of the detection tubes extracts the radio frequency output signal, and the other detection tube is set at the reference level output by the power reference generating circuit. The two detection tubes are respectively positively detecting the reference level and the coupled radio frequency signal, and the two detection signals pass through the error. The summation circuit calculates the difference by common-mode integration, and the output signal of the error summation circuit drives the power modulator.

Optionally, the above pair of detector tubes are in the same package.

Based on the high-stable power control circuit for common-mode temperature compensation detection described above, the present invention also provides a high-stable power control method for common-mode temperature compensation detection. The peacefully coupled radio frequency signal is positively detected at the same time, and the two detection signals are differenced through common-mode integration to drive the power modulator.

The beneficial effects of the present invention are:

(1) High power control temperature stability and precise control;

(2) The circuit is simple, easy to realize and low in cost.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the functional block diagram of existing automatic level control system;

Fig. 2 is a schematic block diagram of a high stable power control circuit for common-mode temperature compensation detection of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention provides a high-stable power control circuit and method for common-mode temperature-compensated detection. The temperature characteristics of a pair of detection tubes are used to realize the output power stability of radio frequency signals less than 5‰, thereby achieving high stability of radio frequency signal power.

As shown in Figure 2, a highly stable power control circuit for common-mode temperature compensation detection of the present invention includes: a power modulator, an amplifier circuit, a directional coupler (not shown in the figure), a wave detector, a power reference generation circuit, In the error summation circuit, the detector includes a pair of detector tubes.

As mentioned above, the traditional ALC system cannot meet the requirement of high power stability. The invention improves the ALC loop and adds a detector at the reference level. One detector tube extracts the RF output signal, and the other detector tube is set at the power reference level. At the reference level output by the generating circuit, a pair of detector tubes is used to detect the reference level and the coupled RF signal at the same time. The reference level here is the preset power level, and the data from the CPU is converted into Reference level, DAC temperature characteristic ±20ppm/℃, far higher than the whole system's requirement for high stability of power temperature, two-way detection through common-mode integration to find the difference, drive the power modulator, to achieve the purpose of controlling the power of the RF output signal, Due to the temperature characteristics of the power detection tube, that is, the detection size changes with the temperature, now a pair of detection tubes are used for simultaneous detection to compensate the drift of the RF output power caused by the temperature characteristics of the detection tubes. The temperature characteristics of the two detection tubes at the same temperature can be They cancel each other out, which eliminates the fluctuation of the radio frequency output power caused by the temperature characteristics of the detector tube, and greatly improves the ability of power temperature stability. Preferably, the pair of detector tubes are in the same package.

When the preset reference level becomes larger, the voltage driving the power modulator will become larger after the sum of the common-mode errors, and the RF signal entering the amplifier will become larger. In the linear operating range of the amplifier, the RF output power will also change. Large, at this time, the detection voltage through the RF coupling terminal will also increase. When the voltage of the RF coupling detection is equal to the voltage of the reference voltage detection, the entire loop is maintained in a constant state to ensure that the RF output power is stable in a constant state. down, and vice versa.

When the power of the RF output signal becomes larger, the detected voltage of the RF signal increases after coupling. When the reference level remains unchanged, the voltage driving the power modulator becomes smaller through the sum of the common mode errors, and enters the amplifier RF When the signal becomes smaller, within the linear operating range of the amplifier, that is, when the amplifier has not yet entered a saturated state, the power of the entire RF output signal becomes smaller. Through the closed-loop feedback, the stability of the RF output power is maintained, and vice versa.

Based on the above-mentioned high stable power control circuit for common-mode temperature compensation detection, the present invention also proposes a high-stable power control method for common-mode temperature compensation detection. The peacefully coupled RF signal is positively detected at the same time. The reference level here is the preset power level. The data from the CPU is converted into a reference level through a high-performance DAC. The temperature characteristic of the DAC is ±20ppm/℃, which is much higher than that of the entire system. For the requirement of high stability of power temperature, the two-way detection uses the common mode integral to find the difference to drive the power modulator.

The high-stable power control circuit and method for common-mode temperature compensation detection of the present invention have the characteristics of high power control temperature stability, precise control, simple and easy implementation of the circuit, and low cost.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (3)

1. A highly stable power control circuit for common-mode temperature compensation detection, comprising: a power modulator, an amplifier circuit, a directional coupler, a wave detector, a power reference generating circuit, and an error summation circuit, wherein the wave detector It includes a pair of detector tubes, one of which extracts the radio frequency output signal, and the other detector tube is set at the reference level output by the power reference generating circuit, and the two detector tubes respectively detect the reference level and the coupled radio frequency signal at the same time, The difference of the two detection signals is obtained through the common-mode integration of the error summation circuit, and the output signal of the error summation circuit drives the power modulator. 2. A highly stable power control circuit for common-mode temperature compensation detection as claimed in claim 1, wherein the pair of detection tubes are in the same package. 3. a kind of control method based on the high stable power control circuit of common-mode temperature compensation detection described in claim 1, it is characterized in that, increase one-way detection at reference level place, utilize a pair of detection tubes to reference level and coupling radio frequency signal At the same time, the positive detection is performed, and the difference of the two detection signals is obtained through common-mode integration to drive the power modulator.