FM TRANSMITTER AND NON-FM RECEIVER INTEGRATED ON SINGLE CHIP

摘要

PROBLEM TO BE SOLVED: To efficiently implement a frequency modulation (FM) transmitter and a non-FM receiver on the same IC chip.SOLUTION: The FM transmitter includes a digital FM modulator, a lowpass filter, an amplifier, and an LC tank circuit. The digital FM modulator receives a digital input signal, performs FM modulation with the digital input signal, and provides a digital FM signal. The lowpass filter filters the digital FM signal and provides a filtered FM signal. The amplifier amplifies the filtered FM signal and provides an output FM signal. The LC tank circuit filters the output FM signal. The digital FM modulator performs FM modulation by changing a variable divider ratio of a multi-modulus divider within a PLL. A delta-sigma modulator receives the digital input signal and generates a modulator output signal used to obtain the variable divider ratio.