Abstract: Apparatus and method for acquiring and tracking a data signal are disclosed. Two different CDR circuits are configured to acquire and track data based on two different modulation schemes. While in the acquisition mode, the first CDR circuit may acquire data signal by sampling the signal at a reduced clock rate and handover to the second CDR circuit when a preamble is found. Also in the acquisition mode, the data acquisition and tracking circuit may determine the power level of the preamble signal and dynamically adjust the threshold level for the tracking period upon finding of the preamble.

Abstract: Apparatus and method for acquiring and tracking a data signal are disclosed. Two different CDR circuits are configured to acquire and track data based on two different modulation schemes. While in the acquisition mode, the first CDR circuit may acquire data signal by sampling the signal at a reduced clock rate and handover to the second CDR circuit when a preamble is found. Also in the acquisition mode, the data acquisition and tracking circuit may determine the power level of the preamble signal and dynamically adjust the threshold level for the tracking period upon finding of the preamble.

Abstract: An FSK demodulator system with tunable spectral shaping including a pair of quadri-correlators responsive to first and second quadrature signals, one of the pair deriving first and second signals representative of the frequency deviation of the quadrature signals at even integer multiples of the frequency deviation and for resolving the modulated FSK data represented by the quadrature signals and the other of the pair deriving first and second signals representative of the frequency deviation of the quadrature signals at odd integer multiples of the deviation frequency and for resolving the modulated FSK data represented by the quadrature signals, and a delay control circuit for setting a delay to each of the pair of quadri-correlators to control the first and second signals representative of the frequency deviation of the quadrature signals derived by each of the pair of quadri-correlators and generate a tuned spectral response at both even and odd integer multiples of the frequency deviation.

Abstract: A digital frequency measurement system including first and second digital differentiators responsive to first and second digital quadrature signals representative of first and second quadrature modulated input signals that represent binary data having a center frequency equal to a predetermined IF frequency for generating first and second differentiated signals, first and second processing circuits responsive to the first and second digital quadrature signals representative of the modulated input signals and the first and second differentiated signals for multiplying the first differentiated signal by the second quadrature digital representation of the input signals and multiplying the second differentiated signal by the first quadrature digital representation of the input signals to provide first and second multiplied signals, a combining circuit responsive to the first and second multiplied signals for generating a density signal having a pulse density proportional to the frequency of the input signals, a d