Patent ID: 6687293
Filing Date: 2004-02-03
Classification: G01S,G06K,H04B

Abstract:
A pulse position modulation (PPM) decoder, comprising:a synchronizer; a PPM decoder state machine a calibration/reload function a bit down counter; a bit window counter; and a symbol register having a data symbol output, wherein: the synchronizer has a first input adapted to receive a detected PPM signal, a second input connected to an internal oscillator, and an output connected to a first input of the PPM decoder state machine and a first input of the symbol register; the PPM decoder state machine has a second input connected to the internal oscillator, a first output connected to a first input of the calibration/reload function, a second output connected to a second input of the bit down counter and a third output connected to a second input of the bit window counter; the calibration/reload function has a second input connected to the internal oscillator and an output connected to a first input of the bit down counter; the bit down counter has a third input connected to the internal oscillator and an output connected to a first input of the bit window counter; the bit window counter has a third input connected to the internal oscillator, a first output connected to a second input of the symbol register, and a second output connected to a third input of the PPM decoder state machine; and the symbol register has an output comprising symbol data.