Patent ID: 7224759

Claim:
An apparatus to eliminate a frequency-dependent differential phase shift, Δθ, between a double sideband suppressed carrier modulated angular rate information signal and its sinusoidal demodulation reference signal in a gyroscope angular rate sensing circuit, the circuit including a demodulation reference source, said apparatus comprising: a demodulator; a phase shifter in a demodulation reference signal path, the demodulation reference signal path being between the demodulation reference source and said demodulator, said phase shifter configured to adjust a phase of the sinusoidal demodulation reference signal; a phase locked loop (PLL) comprising a phase detector, a servo equalizer, and a dual-frequency, numerically controlled oscillator, said PLL configured to provide a demodulation signal based on the phase shifted demodulation reference signal; and a phase shift command source comprising frequency dependent outputs and configured to provide an input to said phase shifter to command an appropriate phase adjustment, the frequency dependent outputs based upon a tuning parameter, β, of a numerically controlled oscillator (NCO) in said PLL that is controlled by the demodulation reference signal.