Digital automatic gain control system and method

Abstract

The invention discloses a digital automatic gain control system and method. The digital automatic gain control system includes a DC calculation module, a gain adjustment module, an amplitude limiter,a cordic modulo module, an IIR low pass filter, an error control module, a gain calculation module, and a gain limiting module, wherein the gain adjustment module, the amplitude limiter, the cordic modulo module, the IIR low pass filter, the error control module, the gain calculation module, and the gain limiting module are sequentially cyclically communicated and connected; the DC calculation module is in communication connection with the gain adjustment module through a subtractor; and the IIR low pass filter is connected to the error control module through a summator. The digital automaticgain control system adopts addition, subtraction, multiplication and shifting operations to complete feedback control, is simpler in hardware implementation, and has a greater AGC dynamic adjustment range, wherein the system adjustment time is controllable in three shifts. Besides, the DC filter and the IIR first-order filter are used to solve the problem that the convergence speed of the controlalgorithm under an AM signal is slow or not convergent.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a digital automatic gain control system and method. Background technique [0002] In the software radio, especially the receiving system, the strength of the received signal will vary greatly with the channel environment and receiving conditions. Although the high-resolution ADC has a large dynamic range, the signal is still relatively small. Will have a great impact on receiving performance. The fence ensures that the size of the received signal can be within the expected range, and the received signal amplitude must be adjusted in real time to reduce the impact of signal fluctuations on the system, thereby improving the demodulation performance of the receiving system; in the receiving system, automatic Gain Control (AGC) to solve this problem. [0003] Such as figure 1 As shown, the current superheterodyne receiver structure includes two AGCs. The first-st...

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Problems solved by technology

[0004] Aiming at the above-mentioned deficiencies in the prior art, the digital automatic gain control system and method provided by the present invention solve the problem that the existing automatic gain control method has poor ability to regulate AM signals and deteriorates the signal-to-noise ratio of AM signals

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