Method for tuning a bandpass analog-to-digital converter and associated architecture

A method for tuning a tunable bandpass analog-to-digital converter (ADC), comprising:

• converting an analog input signal to a digital output signal using a tunable bandpass analog-to-digital converter (ADC), the bandpass ADC utilizing a tuning signal to tune the bandpass ADC by adjusting a notch location for the bandpass ADC;
• digitally processing the digital output signal to generate a baseband output signal;
• determining a noise energy level in the baseband output signal;
• modifying the tuning signal applied to the bandpass ADC;
• and
• repeating the converting, processing, determining and modifying steps to adjust the tuning signal so that the noise energy level in the baseband output signal tends to be reduced;
• wherein the analog input signal comprises a channel signal spectrum including a plurality of channels within a frequency range;
• wherein the tunable bandpass ADC is tuned to a desired channel within the channel signal spectrum;
• wherein the baseband output signal is representative of the desired channel;
• and
• wherein the signal spectrum comprises a channel signal spectrum from satellite communications, the satellite channel signal spectrum comprising a plurality of transponder channels with each transponder channel including a plurality of program channels.

A method for tuning a tunable bandpass analog-to-digital converter (ADC), comprising:

• filtering an analog input signal with a tunable bandpass filter,
• converting the filtered analog input signal to a digital output signal using a tunable bandpass analog-to-digital converter (ADC), the bandpass ADC utilizing a tuning signal to tune the bandpass ADC by adjusting a notch location for the bandpass ADC,
• digitally processing the digital output signal to generate a baseband output signal;
• determining a noise energy level in the baseband output signal;
• modifying the tuning signal applied to the bandpass ADC;
• and
• repeating the converting, processing, determining and modifying steps to adjust the tuning signal so that the noise energy level in the baseband output signal tends to be reduced;
• wherein the method further comprises configuring the tunable bandpass ADC as a master circuit and configuring the tunable bandpass filter as a slave circuit such that the tunable bandpass filter is created from circuit elements that are similar to those used in the tunable bandpass ADC, and utilizing a slave tuning signal to tune the tunable bandpass filter, the slave tuning signal matching the master tuning signal used to tune the tunable bandpass ADC.

A tunable analog-to-digital conversion system, comprising:

• a tunable bandpass analog-to-digital converter (ADC) coupled to receive an analog input signal and configured to utilize a tuning signal to tune a notch location for the bandpass ADC;
• digital processing circuitry coupled to receive a digital output signal from the bandpass ADC and configured to output a baseband output signal;
• an energy detector coupled to receive the baseband output signal and configured to determine a noise energy level in the baseband output signal;
• control circuitry coupled to the energy detector and having the tuning signal as an output, the
• control circuitry being configured to adjust the tuning signal so that the noise energy level in the baseband output signal tends to be reduced;
• and
• input selection circuitry coupled to the input of the bandpass ADC, the input selection circuitry configured to allow a predetermined calibration signal or a channel signal spectrum as the input signal to the bandpass ADC, and the input selection circuitry configured to receive a selection control signal from the control circuitry;
• wherein the channel signal spectrum comprises a plurality of channels within a frequency range;
• wherein the tunable bandpass ADC is configured to be tuned to a desired channel within the channel signal spectrum;
• and wherein the baseband output signal is representative of the desired channel.

A tunable analog-to-digital conversion system, comprising:

• a tunable bandpass filter coupled to receive an analog input signal and configured to provide a filtered analog input signal to the tunable bandpass ADC;
• a tunable bandpass analog-to-digital converter (ADC) coupled to receive the filtered analog input signal and configured to utilize a tuning signal to tune a notch location for the bandpass ADC;
• digital processing circuitry coupled to receive a digital output signal from the bandpass ADC and configured to output a baseband output signal;
• an energy detector coupled to receive the baseband output signal and configured to determine a noise energy level in the baseband output signal;
• and
• control circuitry coupled to the energy detector and having the tuning signal as an output, the control circuitry being configured to adjust the tuning signal so that the noise energy level in the baseband output signal tends to be reduced, and
• wherein the tunable bandpass ADC is configured as a master circuit and the tunable bandpass filter is configured as a slave circuit such that the tunable bandpass filter is created from circuit elements that are similar to those used in the tunable bandpass ADC, and
• wherein a slave tuning signal is utilized to tune the tunable bandpass filter, the slave tuning signal matching the master tuning signal used to tune the tunable bandpass ADC.

A receiver for tuning a channel within a signal spectrum, comprising:

• local oscillator (LO) circuitry having a channel selection signal as an input and having a coarse-tune analog mixing signal as an output, the output mixing signal being selected from a plurality of predetermined output mixing signals depending upon a desired channel to be tuned;
• analog coarse tune circuitry having the coarse-tune analog mixing signal as an input and having a signal spectrum as an input, the signal spectrum including a plurality of channels within a frequency range, and the analog coarse tune circuitry being configured to use the coarse tune analog mixing signal to output a coarsely tuned signal spectrum;
• a tunable bandpass analog-to-digital converter (ADC) coupled to receive the coarsely tuned signal spectrum as an input and configured to utilize a tuning signal to tune a notch location for the bandpass ADC, the tunable bandpass ADC being tuned to a desired channel within the plurality of channels;
• digital processing circuitry coupled to receive a digital output signal from the bandpass ADC and configured to output a baseband output signal representative of the desired channel;
• an energy detector coupled to receive the baseband output signal and configured to determine a noise energy level in the baseband output signal;
• and
• control circuitry coupled to the energy detector and having the tuning signal as an output, the control circuitry being configured to adjust the tuning signal so that the noise energy level in the baseband output signal tends to be reduced.

A satellite set-top box for tuning a program channel within a satellite signal spectrum using a receiver that includes a tunable bandpass analog-to-digital converter (ADC), comprising:

• a receiver configured to receive a satellite signal spectrum including a plurality of transponder channels and to tune a transponder channel within the signal spectrum, each transponder channel including a plurality of program channels, comprising:
• local oscillator (LO) circuitry having a channel selection signal as an input and having a coarse-tune analog mixing signal as an output, the output mixing signal being selected from a plurality of predetermined output mixing signals depending upon a desired channel to be tuned;
• analog coarse tune circuitry having the coarse-tune analog mixing signal as an input and having a signal spectrum as an input, the signal spectrum including a plurality of channels within a frequency range, and the analog coarse tune circuitry being configured to use the coarse-tune analog mixing signal to output a coarsely tuned signal spectrum;
• a tunable bandpass analog-to-digital converter (ADC) coupled to receive the coarsely tuned signal spectrum as an input and configured to utilize a tuning signal to tune a notch location for the bandpass ADC, the tunable bandpass ADC being tuned to a desired channel within the plurality of channels;
• digital processing circuitry coupled to receive a digital output signal from the bandpass ADC and configured to output a baseband output signal representative of the desired channel;
• an energy detector coupled to receive the baseband output signal and configured to determine a noise energy level in the baseband output signal;
• and
• control circuitry coupled to the energy detector and having the tuning signal as an output, the control circuitry being configured to adjust the tuning signal so that the noise energy level in the baseband output signal tends to be reduced;
• and
• a demodulator coupled to receive a digital baseband output signal from the receiver representative of a tuned transponder channel, the demodulator being configured to tune a program channel within the tuned transponder channel and to provide the tuned program channel as an output.