Synchronous AM demodulator with quadrature signal cancellation
First Claim
1. A method of removing a quadrature error signal component from a synchronous signal in a synchronous AM demodulator network having a phase reference signal, comprising the steps of:
- (a) generating a counteracting signal, phase related in stable manner to the system phase reference signal; and
(b) mixing said counteracting signal with said synchronous signal, wherein said counteracting signal subtracts from the quadrature error signal component of said synchronous signal.
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Abstract
A method and apparatus for removing quadrature error signal components from synchronous AM demodulation signals are disclosed. A synchronous AM demodulator processes a synchronous sensor output signal in phase relation to a phase reference signal. Means are provided for dynamically producing a counteracting signal that is stably phase related to the system reference signal. The counteracting signal is in phase with the quadrature component of the synchronous signal such that when added to the synchronous signal, the quadrature component thereof is minimized or eliminated.
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Citations
15 Claims
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1. A method of removing a quadrature error signal component from a synchronous signal in a synchronous AM demodulator network having a phase reference signal, comprising the steps of:
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(a) generating a counteracting signal, phase related in stable manner to the system phase reference signal; and (b) mixing said counteracting signal with said synchronous signal, wherein said counteracting signal subtracts from the quadrature error signal component of said synchronous signal. - View Dependent Claims (2, 3, 4)
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5. In combination with a synchronous AM demodulator circuit of the type suitable for demodulating a synchronous signal having a quadrature component, circuit means operatively connected with said demodulator circuit for dynamically minimizing said quadrature component of said synchronous signal.
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6. A quadrature corrector demodulator circuit comprising:
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(a) synchronous AM demodulator circuit means operatively connected to receive a synchronous input signal and a synchronous phase reference input signal, for providing a demodulated output signal responsive thereto;
said synchronous signal including a quadrature signal component;(b) counteracting signal producing circuit means operatively connected to receive said synchronous input signal and said phase reference input signal for dynamically generating in response thereto a counteracting signal that is stable and phase related to said synchronous phase reference signal; and (c) mixing circuit means operatively connected to receive said synchronous input signal and said counteracting signal for summing said signals;
wherein said counteracting signal tends to cancel said quadrature signal component of said synchronous signal. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A vibratory element sensor apparatus comprising:
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(a) a vibratory element sensor of the type that produces a sensed synchronous output signal in response to an impressed force; (b) drive means for driving said sensor with a phase reference signal; (c) synchronous AM demodulator circuit means operatively connected to receive said sensed synchronous output signal and said phase reference signal, for producing a demodulated output signal responsive thereto, said sensed synchronous output signal including a quadrature signal component; (d) counteracting signal producing circuit means operatively connected to receive said sensed synchronous output signal and said phase reference signal for dynamically generating in response thereto a counteracting signal that is phase related, in stable manner, to said phase reference signal; and (e) mixing circuit means operatively connected to receive said sensed synchronous output signal and said counteracting signal for summing the two signals;
wherein said counteracting signal tends to cancel said quadrature signal component of said sensed synchronous output signal. - View Dependent Claims (15)
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Specification