Demodulator system and method
First Claim
Patent Images
1. A demodulator system comprising:
- an analog-to-digital converter (ADC) configured to sample a modulated signal and to output a digital signal;
a Coordinate Rotation Digital Computer (CORDIC) mixer coupled to an output of the ADC, the CORDIC mixer to generate an Inphase (I) signal and a Quadrature (Q) signal based on the digital signal output by the ADC and further based on an input frequency;
a filter path to process the I signal and the Q signal generated at the CORDIC mixer; and
a demodulation stage to demodulate an output of the filter path, wherein the demodulation stage includes a CORDIC demodulator.
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Abstract
A demodulator system and method is disclosed. In an embodiment, the demodulator system can include a Coordinate Rotation Digital Computer (CORDIC) mixer to mix a first signal substantially to baseband using a first input frequency and to mix a second signal substantially to baseband using a second input frequency. In another embodiment, the demodulator system can include a phase detector to receive a pilot signal and to generate a control signal to adjust a decimation rate based on the pilot signal. In another embodiment, the demodulator system can include a symbol decoder to determine a symbol from a phase signal.
76 Citations
30 Claims
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1. A demodulator system comprising:
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an analog-to-digital converter (ADC) configured to sample a modulated signal and to output a digital signal; a Coordinate Rotation Digital Computer (CORDIC) mixer coupled to an output of the ADC, the CORDIC mixer to generate an Inphase (I) signal and a Quadrature (Q) signal based on the digital signal output by the ADC and further based on an input frequency; a filter path to process the I signal and the Q signal generated at the CORDIC mixer; and a demodulation stage to demodulate an output of the filter path, wherein the demodulation stage includes a CORDIC demodulator. - View Dependent Claims (2, 3, 4, 5)
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6. A demodulator system comprising:
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a Coordinate Rotation Digital Computer (CORDIC) mixer to receive a first input signal modulated using a first modulation mode and to generate a first Inphase (I) signal and a first Quadrature (Q) signal by mixing the first input signal substantially to baseband using a first input frequency, the CORDIC mixer further to receive a second input signal modulated using a second modulation mode and to generate a second I signal and a second Q signal by mixing the second input signal substantially to baseband using a second input frequency; a filter path to process an output of the CORDIC mixer; and a demodulation stage to demodulate an output of the filter path, wherein the demodulation stage includes a CORDIC demodulator. - View Dependent Claims (7)
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8. A demodulator system comprising:
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a Coordinate Rotation Digital Computer (CORDIC) mixer to generate an Inphase (I) signal and a Quadrature (Q) signal based on a modulated input signal and an input frequency; a decimator to perform decimation of the I signal and the Q signal at an adjustable decimation rate; a phase detector to receive a pilot signal and including decimation rate logic to generate a control signal to adjust the decimation rate based on the pilot signal, wherein an oversample rate of the pilot signal is not less than approximately two and not more than approximately sixty-four; and a demodulation stage to demodulate a filtered output of the decimator, wherein the demodulation stage includes a CORDIC demodulator. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A demodulator system comprising:
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a Coordinate Rotation Digital Computer (CORDIC) mixer to generate an Inphase (I) signal and a Quadrature (Q) signal; a decimator coupled to the CORDIC mixer to adjust a sample rate of at least one of the I signal and the Q signal; a filter path coupled to the decimator to process an output of the decimator; a demodulation stage to demodulate an output of the filter path, wherein the demodulation stage includes a CORDIC demodulator, and a symbol decoder to receive a phase signal from the CORDIC demodulator, the symbol decoder including symbol recognition logic to adjust a sample of the phase signal by an offset value, to map the adjusted sample to a nearest predetermined phase value of a plurality of predetermined phase values, and to determine a symbol using a difference between the nearest predetermined phase value and a prior nearest predetermined phase value, wherein the offset value at least partially compensates for a phase drift generated at the CORDIC mixer. - View Dependent Claims (18, 19, 20, 21)
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22. A demodulation method comprising:
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receiving a modulated signal; mixing the audio signal substantially to baseband at a Coordinate Rotation Digital Computer (CORDIC) mixer having multiple pipelined mixing stages; decimating an output of the CORDIC mixer at a decimator having an adjustable decimation rate; and demodulating a filtered output of the decimator with a CORDIC demodulator. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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Specification