FPGA (field programmable gate array) based digital AGC (automatic gain control) system and method of ultra-short wave radio set

Abstract

The invention relates to a FPGA (field programmable gate array) based digital AGC (automatic gain control) system and method of an ultra-short wave radio set. An RF (radio frequency signal) IN of a receiver is sent to a digital attenuator I to achieve an IF (intermediate frequency) signal through a mixer. One part of the IF signal enters a digital attenuator II, and the other part of the IF signal enters a detector for the detection. An IF-RSSI (received signal strength indicator), received by the detector, is converted into a digital signal by an A / D (analog / digital) converter and entered the FPGA. The signal processing is performed to the FPGA by adopting the sliding window smoothing algorithm to acquire average value of the IF signal. The FPGA judges according to the IF-RSSI. The digital attenuator I and the digital attenuator II are controlled through RFAGC (radio frequency automatic gain control), IFAGC 1(intermediate frequency automatic gain control) and IFAGC2, and a variable gain amplifier is controlled through an SPI interface to achieve constant output of the IF signal. By the use of the FPGA-based digital AGC system and method, automatic gain control on the RF signal reception is achieved within a wide dynamic range, thus the IF signal is maintained within a stable range, and smooth output of the IF signal is realized.

Description

technical field [0001] The present invention relates to a digital AGC automatic gain control system and method, in particular to an FPGA-based digital AGC control system and method for ultrashort wave radio stations that can perform automatic gain control on wide dynamic range radio frequency signals . Background technique [0002] The function of the AGC circuit is to realize automatic gain control within a wide dynamic range of the system, and it is widely used in systems with a large dynamic range such as military radio stations, smart antennas, wireless communication systems, medical care, and disk reading channels. The AGC circuit can adjust the gain of these systems so that signals that vary in a wide range can output a stable output level. [0003] Due to the influence of factors such as the size of the transmitting power, the distance of sending and receiving, and the fading of electromagnetic wave propagation, the range of variation of the input signal of the recei...

AI Technical Summary

Problems solved by technology

However, the invention patent only amplifies or attenuates the intermediate frequency signal, and does not perform AGC processing on the received RF signal. When the input signal is large, the front-end analog device is likely to cause nonlinearity or even be damaged; and the invention patent is The intermediate frequency signal is subjected to AD sampling and related processing, the AGC processing delay is too long, and the adjustment time is relatively slow

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