Patent ID: 7860187
Filing Date: 2010-12-28
Classification: H04L

Abstract:
1. A frequency shift keying (FSK) signal modulator for receiving information to be transmitted to produce an FSK signal, comprising: a counter for determining a count value by adding an addition value modified in accordance with a predetermined rule depending on a data value specified by the information to be transmitted and for holding the count value; and a decision circuit for comparing the count value to a threshold value for a decision and for producing the FSK signal of a binary which is in keeping with a result of the decision, wherein, in the predetermined rule, when a center frequency Fq_if of an input modulation frequency component of an opposite FSK demodulator and frequencies Fq_m and Fq_s of the FSK signal respectively corresponding to the data value of “0” and “1” are used to determine integer values a, b and c, which satisfy the following condition: and when a symbol rate Sb of a modulation signal and an input sampling frequency Spf of the opposite FSK demodulator are used to determine an integer value d which satisfies the following condition: said addition value is determined on basis of the integer values b, c and d and the data value.