Patent ID: 6980609

Claim:
A digital passband matched filter having a carrier recovery section for converting a passband digital signal of a specific channel into a baseband digital signal, removing a frequency offset and a phase jitter by demodulating the passband digital signal into a complex carrier frequency, the matched filter comprising: a control signal generation section for generating a coefficient renewal control signal to control a renewal of a passband matched filter to each N+1 (N=(L−1)/2, L: a tap number) sample of a cosine wave address of M bits (M: a natural number) and a baseband filter selection address of K bits (K: a natural number) adapted to the carrier frequency outputted from the carrier recovery section; a cosine generation section for storing a cosine wave corresponding to 0~2π, and generating a cosine wave corresponding to the cosine wave address; a baseband filter coefficient output section for storing the baseband matched filter coefficient according to a number of N+1 (N=(L−1)/2, L: a tap number) samples, and selectively outputting the baseband matched filter coefficients in accordance with the baseband filter selection address; a passband filter coefficient generation section for generating passband matched filter coefficients adapted to the carrier frequency by convoluting the baseband matched filter coefficients outputted from the baseband filter coefficient output section according to the cosine wave generated in the cosine generation section in a proper frequency region, and outputting the passband matched filter coefficients in accordance with the coefficient renewal control signal; and a L-tap Finite Impulse Response (FIR) filter for convoluting the passband digital signal in a time axis based on a filter coefficient of the passband matched filter coefficients outputted from the passband filter coefficient generation section.