Receiver architectures utilizing coarse analog tuning and associated methods
First Claim
1. A method for tuning a channel within a signal spectrum, comprising:
- receiving a signal spectrum including a plurality of channels within a frequency range;
receiving a channel selection signal identifying at least one desired channel to be tuned;
selecting one of a plurality of predetermined analog mixing signals depending upon a location of the desired channel within the signal spectrum;
mixing the signal spectrum with the selected analog mixing signal to mix the desired channel down to a variable location within a frequency range around DC and not to a fixed target frequency, the variable location being dependent upon the location of the desired channel within the signal spectrum arid the selected analog mixing signal;
converting the desired channel at the variable frequency location to digital signals; and
digitally processing the digital signals.
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Abstract
Receiver architectures and associated methods are disclosed that provide initial analog coarse tuning of desired channels within a received signal spectrum, such as a set-top box signal spectrum for satellite communications. These architectures provide significant advantages over prior direct down-conversion (DDC) architectures and low intermediate-frequency (IF) architectures, particularly where two tuners are desired on the same integrated circuit. Rather than using a low-IF frequency or directly converting the desired channel frequency to DC, initial coarse tuning provided by analog coarse tuning circuitry allows for a conversion to a frequency range around DC. This coarse tuning circuitry can be implemented, for example, using a large-step local oscillator (LO) that provides a coarse tune analog mixing signal. Once mixed down, the desired channel may then be fine-tuned through digital processing, such as through the use of a wide-band analog-to-digital converter (ADC) or a narrow-band tunable bandpass ADC.
56 Citations
20 Claims
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1. A method for tuning a channel within a signal spectrum, comprising:
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receiving a signal spectrum including a plurality of channels within a frequency range; receiving a channel selection signal identifying at least one desired channel to be tuned; selecting one of a plurality of predetermined analog mixing signals depending upon a location of the desired channel within the signal spectrum; mixing the signal spectrum with the selected analog mixing signal to mix the desired channel down to a variable location within a frequency range around DC and not to a fixed target frequency, the variable location being dependent upon the location of the desired channel within the signal spectrum arid the selected analog mixing signal; converting the desired channel at the variable frequency location to digital signals; and
digitally processing the digital signals. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A receiver for tuning a channel within a signal spectrum, comprising:
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mixing circuitry having an 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; local oscillator (LO) circuitry having a channel selection signal as an input and having the analog mixing signal as an output, the analog mixing signal being selected from a plurality of predetermined analog mixing signals depending upon a location of a desired channel to be tuned within the signal spectrum such that the desired channel is mixed down to a variable location within a frequency range around DC and not to a fixed target frequency, the variable location being dependent upon the location of the desired channel within the signal spectrum and the selected analog mixing signal; analog to digital conversion circuitry configured to convert the desired channel at the variable frequency location to digital signals; and digital processing circuitry configured to digitally process the digital signals. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A satellite set-top box for tuning a program channel within a satellite signal spectrum, comprising:
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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; mixing circuitry having an 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; local oscillator (LO) circuitry having a channel selection signal as an input and having the analog mixing signal as an output, the analog mixing signal being selected from a plurality of predetermined analog mixing signals depending upon a desired channel to be tuned such that desired channels are mixed down to variable locations with a frequency range around DC based upon the desired channel and the selected analog mixing signal rather than being mixed down to a fixed frequency; and digital processing circuitry having an output from the mixing circuitry as an input and having as an output digital baseband signals for the desired channel; 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. - View Dependent Claims (19, 20)
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Specification