Patent ID: 6738433
Filing Date: 2004-05-18
Classification: H03D

Abstract:
A quadricorrelator for a demodulator for frequency-modulated signals, comprising:a first input for receiving an in-phase component of a signal to be demodulated, and a second input for receiving a quadrature component of the signal to be demodulated; a first multiplier unit connected to said first input and having an output, and a second multiplier unit connected to said second input and having an output, an output adder unit having a first input connected with a positive sign to said output of said first multiplier unit, a second input connected with a negative sign to said output of said second multiplier unit, and an output forming an output of the quadricorrelator; said second multiplier unit receiving as an input signal the in-phase component from said first input via a first transfer function, and said first multiplier unit receiving as an input signal the quadrature component from said second input via a second transfer function; the first and second transfer functions being chosen such that a demodulator characteristic formed between said input of the quadricorrelator and said output of said output adder unit cuts a frequency axis at a point where the frequency is not zero and runs essentially linearly in a sufficiently wide frequency band surrounding or adjacent to the intersection point; and wherein said first transfer function comprising a first, transfer function element applied to the in-phase component, and a second transfer function element applied to an input signal to said first multiplier unit, wherein signals weighted by said first transfer function element and said second transfer function element are added to generate an added signal forming the input signal to said second multiplier unit; and said second transfer function comprising a first transfer function element applied to the quadrature component, and a second transfer function element applied to the input signal to said second multiplier unit, wherein the signals weighted by said first transfer function element and said second transfer function element are added to generate an added signal forming the input signal to said first multiplier unit.