Methods and apparatus for synchronization in multiple-channel communication systems
Methods and apparatus for processing multichannel signals in a multichannel receiver are described. In one implementation, a plurality of demodulator circuits may provide a plurality of outputs to a processing module, with the processing module then simultaneously estimating noise characteristics based on the plurality of outputs and generating a common noise estimate based on the plurality of outputs. This common noise estimate may then be provided back the demodulators and used to adjust the demodulation of signals in the plurality of demodulators to improve phase noise performance.
1. A system comprising:
a plurality of demodulator circuits, each of said plurality of demodulator circuits comprising an equalizer circuit; and
a processor circuit, wherein:
each equalizer circuit is configured to generate a channel estimate based on a respective channel of a multichannel signal;
said processor circuit is configured to generate a common channel estimate based on said channel estimates from each equalizer circuit of said plurality of demodulator circuits; and
each of said plurality of demodulator circuits is configured to demodulate a respective channel of said multichannel signal with use of a corresponding respective one of said channel estimates and said common channel estimate.
2. The system of claim 1 , wherein each of said plurality of demodulator circuits is configured to correct for noise in said multichannel signal based on said common channel estimate.
3. The system of claim 1 , comprising a radio front end configured to downconvert and filter said multichannel signal to output each channel of said multichannel signal to a respective one of said plurality of demodulator circuits.
4. The system of claim 1 , comprising:
an in-phase analog-to-digital converter configured to concurrently digitize each channel of said multichannel signal; and
a quadrature-phase analog-to-digital converter configured to concurrently digitize each channel of said multichannel signal.
5. The system of claim 4 , comprising a digital front end circuit which receives an in-phase digital signal generated by said in-phase analog-to-digital converter and a quadrature-phase signal generated by said quadrature-phase analog-to-digital converter.
6. The system of claim 5 , wherein said digital front end circuit is operable to select each channel of said multi-channel signal for conveyance to a respective one of said plurality of demodulator circuits.
7. The system of claim 1 , wherein each of said plurality of demodulator circuits is configured to use said channel estimates to correct noise present in said respective one of said plurality of channels.
8. The system of claim 1 , wherein said multichannel signal is a channel bonded cable television signal.
9. A method comprising:
in a receiver comprising a plurality of demodulator circuits and a processor circuit, wherein each of said plurality of demodulator circuits comprises an equalizer circuit:
generating, by each equalizer circuit, a channel estimate based on a respective channel of a multichannel signal;
generating, by said processor circuit, a common channel estimate based on said channel estimates from each equalizer circuit of said plurality of demodulator circuits; and
demodulating, by each of said plurality of demodulator circuits, a respective channel of said multichannel signal using a corresponding respective channel estimate and said common channel estimate.
10. The method of claim 9 , comprising correcting, by each of said plurality of demodulator circuits based on said common channel estimate, noise in a respective one of said plurality of channels of said multichannel signal.
11. The method of claim 9 , comprising downconverting and filtering, by a radio front end circuit, said multichannel signal to output each channels of said multichannel signal to a respective one of said plurality of demodulator circuits.
12. The method of claim 9 , comprising concurrently digitizing, by an in-phase analog-to-digital converter circuit and a quadrature-phase analog-to-digital converter circuit, each channel of said multichannel signal.
13. The method of claim 12 , comprising receiving, by a digital front end circuit, an in-phase digital signal generated by an in-phase analog-to-digital converter and a quadrature-phase signal generated by a quadrature-phase analog-to-digital converter.
14. The method of claim 13 , comprising selecting, by said digital front end circuit, each channel of said multichannel signal for conveyance to a respective one of said plurality of demodulator circuits.
15. The method of claim 9 , correcting, by each of said plurality of demodulator circuits, noise present in a respective channel of said multichannel signal using a respective channel estimate.
16. The method of claim 9 , wherein said multichannel signal is a channel bonded signal cable television signal.