Quadrature signal processor using single analog-to-digital converter unit

A system, comprising:

• an input terminal configured to receive a quadrature signal;
• a decoder configured to process the quadrature signal into an analog in-phase component signal and an analog quadrature component signal;
• a first multiplexer coupled to the decoder and including a first output terminal, the first multiplexer being configured to:
• receive the analog in-phase component signal,
• receive the analog quadrature component signal,
• receive a first control signal, and
• at a frequency determined by the first control signal, alternately output the analog in-phase component signal and the analog quadrature component signal at the output terminal as a first multiplexer output signal;
• an analog-to-digital converter configured to:
• sample analog values from the first multiplexer output signal,
• convert the analog values into corresponding digital values, and
• output the digital values as a digital output stream;
• a demultiplexer connected to the analog-to-digital converter, the demultiplexer being configured to:
• receive the digital output stream,
• receive a second control signal, and
• at a frequency determined by the second control signal, alternately output the digital output stream at a first output terminal of the demultiplexer as a digital representation of the in-phase component signal and a second output terminal of the demultiplexer as a digital representation of the quadrature component signal;
• and
• a filter system configured to impose a one-half sampling period delay on at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal, wherein a sampling period is equal to an inverse of a frequency of the first control signal;
• wherein the filter system exhibits a linear phase-response to effect a time delay on an input signal to the filter system;
• wherein coefficients of the filter system are determined by:
• determining a filter kernel including a first set of coefficients;
• upsampling the filter kernel by a factor by interpolating the first set of coefficients to determine a first set of modified filter coefficients;
• delaying the first set of modified filter coefficients by a number of samples to determine a second set of modified filter coefficients, wherein the number of samples is determined by the factor;
• and
• downsampling the filter kernel by the factor by interpolating the second set of modified filter coefficients by the factor to determine the coefficients of the filter system.

A system, comprising:

• an input terminal configured to receive a quadrature signal;
• a decoder configured to process the quadrature signal into an analog in-phase component signal and an analog quadrature component signal;
• a first multiplexer coupled to the decoder and including a first output terminal, the first multiplexer being configured to:
• receive the analog in-phase component signal,
• receive the analog quadrature component signal,
• receive a first control signal, and
• at a frequency determined by the first control signal, alternately output the analog in-phase component signal and the analog quadrature component signal at the output terminal as a first multiplexer output signal;
• an analog-to-digital converter configured to:
• sample analog values from the first multiplexer output signal,
• convert the analog values into corresponding digital values, and
• output the digital values as a digital output stream;
• a demultiplexer connected to the analog-to-digital converter, the demultiplexer being configured to:
• receive the digital output stream,
• receive a second control signal, and
• at a frequency determined by the second control signal, alternately output the digital output stream at a first output terminal of the demultiplexer as a digital representation of the in-phase component signal and a second output terminal of the demultiplexer as a digital representation of the quadrature component signal;
• and
• a filter system configured to impose a one-half sampling period delay on at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal, wherein a sampling period is equal to an inverse of a frequency of the first control signal;
• wherein the frequency determined by the first control signal is twice a frequency of a sampling frequency of the system.

A system, comprising:

• a first input configured to receive an analog in-phase component signal of a quadrature signal;
• a second input configured to receive an analog quadrature component signal of the quadrature signal;
• a multiplexer including a first output terminal, the multiplexer being configured to alternately output the analog in-phase component signal and the analog quadrature component signal at the output terminal as a multiplexer output signal;
• an analog-to-digital converter configured to:
• sample analog values from the multiplexer output signal,
• convert the analog values into corresponding digital values, and
• output the digital values as a digital output stream;
• a demultiplexer connected to the analog-to-digital converter, the demultiplexer being configured to alternately output the digital output stream at a first output terminal of the demultiplexer as a digital representation of the in-phase component signal and a second output terminal of the demultiplexer as a digital representation of the quadrature component signal;
• a filter system configured to impose a one-half sampling period delay on at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal;
• wherein the filter system is configured to upsample at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal by a factor, delay the upsampled signal by a number of samples determined by the factor, and downsample the delayed signal by the factor.

A system, comprising:

• a first input configured to receive an analog in-phase component signal of a quadrature signal;
• a second input configured to receive an analog quadrature component signal of the quadrature signal;
• a multiplexer including a first output terminal, the multiplexer being configured to alternately output the analog in-phase component signal and the analog quadrature component signal at the output terminal as a multiplexer output signal;
• an analog-to-digital converter configured to:
• sample analog values from the multiplexer output signal,
• convert the analog values into corresponding digital values, and
• output the digital values as a digital output stream;
• a demultiplexer connected to the analog-to-digital converter, the demultiplexer being configured to alternately output the digital output stream at a first output terminal of the demultiplexer as a digital representation of the in-phase component signal and a second output terminal of the demultiplexer as a digital representation of the quadrature component signal;
• a filter system configured to impose a one-half sampling period delay on at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal;
• wherein a sampling period is equal to an inverse of an operational frequency of operation of the multiplexer;
• wherein the frequency of operation of the multiplexer is twice a frequency of a sampling frequency of the system.

A system, comprising:

• a first input configured to receive an analog in-phase component signal of a quadrature signal;
• a second input configured to receive an analog quadrature component signal of the quadrature signal;
• a multiplexer including a first output terminal, the multiplexer being configured to alternately output the analog in-phase component signal and the analog quadrature component signal at the output terminal as a multiplexer output signal;
• an analog-to-digital converter configured to:
• sample analog values from the multiplexer output signal,
• convert the analog values into corresponding digital values, and
• output the digital values as a digital output stream;
• a demultiplexer connected to the analog-to-digital converter, the demultiplexer being configured to alternately output the digital output stream at a first output terminal of the demultiplexer as a digital representation of the in-phase component signal and a second output terminal of the demultiplexer as a digital representation of the quadrature component signal;
• a filter system configured to impose a one-half sampling period delay on at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal;
• wherein the filter system exhibits a linear phase-response to effect a time delay on an input signal to the filter system;
• wherein coefficients of the filter system are determined by:
• determining a filter kernel including a first set of coefficients;
• upsampling the filter kernel by a factor by interpolating the first set of coefficients to determine a first set of modified filter coefficients;
• delaying the first set of modified filter coefficients by a number of samples to determine a second set of modified filter coefficients, wherein the number of samples is determined by the factor;
• and
• downsampling the filter kernel by the factor by interpolating the second set of modified filter coefficients by the factor to determine the coefficients of the filter system.

A method, comprising:

• receiving an analog in-phase component signal of a quadrature signal and an analog quadrature component signal of the quadrature signal;
• alternately outputting the analog in-phase component signal and the analog quadrature component signal as a first output signal;
• sampling analog values from the first output signal;
• converting the analog values into corresponding digital values;
• outputting the digital values as a digital output stream;
• alternately output the digital output stream as a digital representation of the in-phase component signal and a digital representation of the quadrature component signal;
• upsampling at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal by a factor of two to generate an upsampled signal;
• delaying the upsampled signal by a single sample to generate a delayed signal;
• and
• downsampling the delayed signal by a factor of two.

A method, comprising:

• receiving an analog in-phase component signal of a quadrature signal and an analog quadrature component signal of the quadrature signal;
• alternately outputting the analog in-phase component signal and the analog quadrature component signal as a first output signal;
• sampling analog values from the first output signal;
• converting the analog values into corresponding digital values;
• outputting the digital values as a digital output stream;
• alternately output the digital output stream as a digital representation of the in-phase component signal and a digital representation of the quadrature component signal;
• upsampling at least one of the digital representation of the in-phase component signal and the digital representation of the quadrature component signal by a factor of four to generate a first upsampled signal;
• delaying the first upsampled signal by a single sample to generate a first delayed signal;
• and
• downsampling the first delayed signal by a factor of four to generate a first output signal.