The frequency synthesis module is mainly used to provide the required LO signals to the three mixers in
the microwave/millimeter-wave frequency conversion module and the fourth mixer in the IF signal
processing module. It consists of seven phase-lock loops of 5.3 GHz ~ 5.55 GHz first LO, 6 GHz ~ 12
GHz second LO, 3,200 MHz third LO and 109 MHz fourth LO, which will directly determine the phase
noise, sweep speed, sideband stray, etc. of the main unit.
2.3 IF Signal Processing Module
It is mainly used to carry out amplification and IF gain modulation of 140.25 MHz third IF signal output by
the microwave/millimeter-wave frequency conversion module, and then make it enter the acoustic
surface wave filter to suppress the out-of-band frequency, and obtain the fourth IF signal by mixing the
third IF signal after gain adjustment on the third IF channel with the fourth local oscillator and make it as
the AD converter input sampling signal. After AD sampling, it will output the LVDS level to the data
processing, display and control module for IF filtering, video detection, digital down-conversion and
video filtering, etc., and finally convert it to the testing curve and display it on the LCD.
2.4 Data Processing, Display and Control Module
It includes the switch power conversion, digital signal processing, display and touch screen driver, all
kinds of user input and output interfaces required by the main unit and logic control functions of each unit
circuit on the main unit. The data processing, display and control module is mainly used to control the
circuit of each module to complete the measurement of the spectrum analyzer and the processing and
display of the measurement data. It also includes auxiliary functions including the processing of
keyboard and touch screen input information, peripheral control, parameter transformation, data and
status storage and recall, measurement result output and cursor, as well as statistical analysis and
functional support of LAN and USB interfaces.
