Internal calibration circuit of microwave power probe and calibration method

Abstract

The invention provides an internal calibration circuit of a microwave power probe. The internal calibration circuit of the microwave power probe includes a microwave power sensor, a multi-core cable and a host power measurement channel; after microwave signals are inputted, a diode detector pair enabling +detection and -detection performs detection, so that +detection voltage and -detection voltage which are opposite to each other and have the same amplitude are outputted; a precise input operational amplifier performs 1:1 reverse amplification on output voltage of a D / A converter; various kinds of compensation data of the probe are stored in an EEPROM; an interface extender controls port output states through an IIC bus and is used for controlling the switching selection of high-speed switches and operating control signals of the D / A converter; and a linear differential amplifier enhances the transmission capability of the signals and transmits the signals to a power meter host through a cable. Compared with a method in which a calibration source plate is arranged inside a host, with the circuit and method of the invention adopted, 2000 yuan to 3000 yuan is expected to be saved, and calibration time is short, and calibration can be completed in one minute.

Description

technical field [0001] The invention relates to the technical field of testing, in particular to an internal calibration circuit of a microwave power probe, and also to an internal calibration method of a microwave power probe. Background technique [0002] In order to ensure the accuracy of the microwave power test, the power sensor and the host need to be calibrated before the test, and the power sensor and the host need to be calibrated to the power standard. [0003] The current existing power standards adopt a calibration source with a fixed frequency and variable power inside the main unit of the power meter. The specific indicators are: [0004] Frequency: 1GHz; [0005] Power range: -40dBm~+20dBm; [0006] Calibration step: 1dB / point; [0007] Calibration time: 120 seconds. [0008] Current solutions with calibration sources inside the power meter host have the following limitations: [0009] (1) High cost: a calibration source circuit board is required inside t...

AI Technical Summary

Problems solved by technology

[0009] (1) High cost: a calibration source circuit board is required inside the host, and the cost is estimated to be 2,000 to 3,000 yuan;

[0010] (2) Poor calibration operability: Calibration needs to move the power probe from the port of the device under test to the output port of the calibration source, and then connect the power probe to the port of the device under test after the calibration is completed, which is inconvenient to operate;

[0011] (3) Long calibration time: the entire calibration process needs to start from +20dBm, calibrate with a step of 1dB / point, and calibrate to -40dBm. The entire calibration process takes about 120 seconds

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