Patent ID: 7623598
Filing Date: 2009-11-24
Classification: H04L

Abstract:
1. An apparatus for demodulation of an analog received signal which is frequency-modulated at the transmitter end with a data symbol sequence {d k }, said apparatus comprising: a detector for zero crossings of the received signal, a sequence generator for production of a sequence {z a calculation unit for reconstruction of the data symbol sequence {d k }, with that data symbol sequence being chosen from the possible data symbol sequences as the sought data symbol sequence {d k } for which the Euclidean distance between the sequence {z i } and a sequence which is calculated at the receiver end is a minimum, with each sequence element in the calculated sequence being formed from a convolution of the data symbol sequence {d k } with a coefficient sequence {h i,k } for the index k, wherein the coefficient sequences {h i,k } are obtained from the times t i and t i+1 , wherein the sequence elements h i,k in the coefficient sequences {h i,k } are defined in such a way that wherein the sequence elements z i are given by the function where ω 0 is the carrier frequency of the unmodulated signal, in that the coefficients h the modulation index ii is given by and the integral q(t) over the elementary pulse shape g(t) is given by where Δω is the modulation shift.