Direct digital conversion tuner and method for using same
View Patent ↗A direct sampling tuner includes a low noise amplifier and an optional dynamically configurable band pass filter coupled to the low noise amplifier. The optional filter is configured to pass a selected band of channels. The tuner further includes a relatively high accuracy, multi-bit analog-to-digital converter (“ADC”) coupled to the LNA or to the optional dynamically configurable band pass filter. The ADC operates at greater than about twice a frequency of a sampled signal. The ADC directly samples the spectrum of the selected channels at the Nyquist rate, thus avoiding image problems presented by conventional tuners.
1. A tuner, comprising:
an amplifier arranged at a front end of the tuner and configured to be a first element of the tuner to receive and amplify an RF signal;
a dynamically configurable band pass filter directly connected to the amplifier and configured to pass a selected band of the amplified RF signal; and
a converter coupled to the dynamically configurable band pass filter, wherein the converter operates at greater than twice a frequency of the selected band of the amplified RF signal.
2. The tuner according to claim 1 , wherein the converter comprises an analog-to-digital converter.
3. The tuner according to claim 2 , wherein the analog-to-digital converter operates at frequencies greater than 1 GHz.
4. The tuner according to claim 2 , wherein the analog-to-digital converter comprises one of a flash analog-to-digital converter, a pipeline analog-to-digital converter, an open loop analog-to-digital converter, between an 8 to 12 bit analog-to-digital converter, or a multiple-stage pipeline analog-to-digital converter wherein each stage of the multiple-stage pipeline analog-to-digital converter comprises one or more bits.
5. The tuner according to claim 2 , wherein the analog-to-digital converter comprises a sample and hold module and 2 n comparators, wherein n equals a number of bits in the sample and hold module.
6. The tuner according to claim 1 , wherein the amplifier comprises a low noise amplifier.
7. The tuner according to claim 1 , further comprising a noise shaping module coupled to the converter.
8. The tuner according to claim 7 , further comprising a digital signal processor coupled to the noise shaping module.
9. The tuner according to claim 1 , wherein the amplifier and the dynamically configurable band pass filter are implemented on a single integrated circuit.
10. The tuner according to claim 1 , wherein the amplifier comprises an autonomous gain control configured to keep an output of the amplifier at a fixed voltage level.
11. A method, comprising:
receiving an RF signal at an amplifier arranged at a front end of a tuner that is a first element of the tuner to receive the RF signal;
amplifying the RF signal using the amplifier;
filtering all but a sub-set of channels of the amplified RF signal using a dynamically configurable band pass filter directly connected to the amplifier; and
converting the sub-set of channels to a digital signal, wherein said converting is performed at a sample rate that is greater than twice a frequency of a highest frequency in the sub-set of channels.
12. The method according to claim 11 , further comprising digitally processing the digital signal to obtain information from the sub-set of channels.
13. The method according to claim 12 , further comprising noise shaping the digital signal.
14. The method according to claim 12 , wherein the digital processing comprises one or more of channel filtering, equalization, demodulation, decimation, and gain control.
15. The method according to claim 11 , wherein said converting comprises interleaving.
16. A tuner, comprising:
an amplifier arranged at a front end of the tuner and configured to be a first element of the tuner to receive and amplify an RF signal;
a dynamically configurable band pass filter directly connected to the amplifier, and configured to receive the amplified RF signal and pass a selected band of the amplified RF signal;
a converter coupled to the dynamically configurable band pass filter; and
a digital signal processor configured to demodulate the selected band of the amplified RF signal.
17. The tuner according to claim 16 , wherein the converter operates at greater than twice a frequency of the selected band of the amplified RF signal.
18. The tuner according to claim 16 , wherein the converter operates at less than twice a carrier frequency of the selected band of the multiple channels, but at greater than twice a frequency of information modulated on the selected band of the multiple channels.