The invention relates to the field of
signal demodulation, in particular to a digital FM
signal demodulator with instant AGC. The digital FM
signal demodulator with instant AGC aims to solve the existing technical problems. Through real-time modulation on signal quantization amplitude by means of the instant AGC, the digital FM signal demodulator solves the problem that
demodulation is high in error rate due to small FM signal quantization amplitude, and increases the accurate rate of
demodulation. The digital FM signal demodulator with instant AGC comprises an ADC unit, an orthorhombic dual-channel digital downconversion unit, an extraction and
filtration unit, an instant AGC unit and the like.
Intermediate frequency signals generated by a
signal generator are input into the ADC unit and quantized into digital signals through the ADC unit, and then the digital signals pass through the orthorhombic dual-channel digital downconversion unit, the extraction and
filtration unit, the instant AGC unit and the like in sequence, wherein the instant AGC unit increases the number of quantization significance bits of I(n) and Q(n) signals to the value of the most significant bit allowed by a
CORDIC module by detecting the number of quantization sign bits of the I(n) and Q(n) signals, and the error rate of demodulation is lowered effectively.