Apparatus for performing a non-integer sampling rate change in a multichannel polyphase filter
First Claim
1. A multichannel polyphase filter for performing a non-integer sampling rate change, the multichannel polyphase filter comprising:
- a processing system for accepting and processing M input channels of data, each sampled at an input sampling rate, wherein M is a positive integer greater than unity, and wherein the processing system is programmed to;
provide a commutator for the multichannel polyphase filter, wherein position of the commutator is decoupled from phase of a filter impulse response selected for the position, thereby allowing the multichannel polyphase filter to be operated at a sampling rate that is a non-integer multiple of the input sampling rate;
operate the multichannel polyphase filter at the non-integer multiple of the input sampling rate to obtain the non-integer sampling rate change;
determine a phase index of the filter impulse response as a function of a decimation rate, an interpolation rate, a starting phase index, and an output sample index of the multichannel polyphase filter, when the multichannel polyphase filter is employed in a modulator; and
determine the phase index of the filter impulse response as a function of M and the decimation rate, the intepolation rate, the starting phase index, a commutator position index, and the output sample index of the multichannel polyphase filter, when the multichannel polyphase filter is employed in a demodulator.
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Accused Products
Abstract
A multichannel polyphase filter (304, 602) includes a processing system (204, 506) for accepting and processing M input channels of data, each sampled at an input sampling rate, wherein M is a positive integer greater than unity. The processing system is programmed to provide a commutator (308, 606) for the multichannel polyphase filter, wherein the position of the commutator is decoupled from the phase of a filter impulse response selected for the position, thereby allowing the multichannel polyphase filter to be operated at a sampling rate that is a non-integer multiple of the input sampling rate. The processing system is further programmed to operate the multichannel polyphase filter at the non-integer multiple of the input sampling rate to obtain a non-integer sampling rate change.
71 Citations
19 Claims
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1. A multichannel polyphase filter for performing a non-integer sampling rate change, the multichannel polyphase filter comprising:
a processing system for accepting and processing M input channels of data, each sampled at an input sampling rate, wherein M is a positive integer greater than unity, and wherein the processing system is programmed to; provide a commutator for the multichannel polyphase filter, wherein position of the commutator is decoupled from phase of a filter impulse response selected for the position, thereby allowing the multichannel polyphase filter to be operated at a sampling rate that is a non-integer multiple of the input sampling rate; operate the multichannel polyphase filter at the non-integer multiple of the input sampling rate to obtain the non-integer sampling rate change; determine a phase index of the filter impulse response as a function of a decimation rate, an interpolation rate, a starting phase index, and an output sample index of the multichannel polyphase filter, when the multichannel polyphase filter is employed in a modulator; and determine the phase index of the filter impulse response as a function of M and the decimation rate, the intepolation rate, the starting phase index, a commutator position index, and the output sample index of the multichannel polyphase filter, when the multichannel polyphase filter is employed in a demodulator. - View Dependent Claims (2, 3, 4, 5)
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6. A modulation engine for facilitating a modulation of M subchannels in parallel, wherein M is a positive integer greater than unity, the modulation engine comprising:
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first processing means, arranged to; accept M baseband signals corresponding to the M subchannels and sampled at a baseband sampling rate; and transform the M baseband signals into M time-domain signals, each sampled at the baseband sampling rate; and a multichannel polyphase filter coupled to the first processing means for performing a non-integer sampling rate change on the M time-domain signals, the multichannel polyphase filter comprising; second processing means for accepting and processing the M time-domain signals, wherein the second processing means is arranged to; provide a commutator for the multichannel polyphase filter, wherein position of the commutator is decoupled from phase of a filter impulse response selected for the position, thereby allowing the multichannel polyphase filter to be operated at a sampling rate that is a non-integer multiple of the sampling rate of the M time-domain signals; determine a phase index of the filter impulse response as a function of a decimation rate, an interpolation rate, a starting phase index, and an output sample index of the multichannel polyphase filter; and operate the multichannel polyphase filter at the non-integer multiple of the sampling rate of the M time-domain signals to obtain the non-integer sampling rate change. - View Dependent Claims (7, 8, 9, 10)
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11. A demodulation engine for facilitating a demodulation of at least two of M subchannels in parallel, wherein M is a positive integer greater than unity, the demodulation engine comprising:
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a multichannel polyphase filter for accepting from a receiver a composite signal derived from the at least two of the M subchannels and for performing a non-integer sampling rate change on the composite signal, the multichannel polyphase filter comprising; first processing means for accepting and processing the composite signal, wherein the first processing means is arranged to; provide a commutator for the multichannel polyphase filter, wherein position of the commutator is decoupled from phase of a filter impulse response selected for the position, thereby allowing the multichannel polyphase filter to be operated at a sampling rate that is a non-integer multiple of the sampling rate of the composite signal; determine a phase index of the filter impulse response as a function of M and a decimation rate, an interpolation rate, a starting phase index, a commutator position index, and an output sample index of the multichannel polyphase filter; and operate the multichannel polyphase filter at the non-integer multiple of the sampling rate of the composite signal to obtain the non-integer sampling rate change, thereby generating at least two rate-changed signals; and second processing means coupled to the multichannel polyphase filter and arranged to transform the at least two rate-changed signals into at least two frequency-domain signals, thereby generating at least two baseband signals. - View Dependent Claims (12, 13, 14)
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15. A transmitter for modulating M subchannels in parallel, wherein M is a positive integer greater than unity, the transmitter comprising:
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first processing means arranged to; accept M baseband signals corresponding to the M subchannels and sampled at a baseband sampling rate; and transform the M baseband signals into M time-domain signals, each sampled at the baseband sampling rate; and a multichannel polyphase filter coupled to the first processing means for performing a non-integer sampling rate change on the M time-domain signals, the multichannel polyphase filter comprising; second processing means for accepting and processing the M time-domain signals, wherein the second processing means is arranged to; provide a commutator for the multichannel polyphase filter, wherein position of the commutator is decoupled from phase of a filter impulse response selected for the position, thereby allowing the multichannel polyphase filter to be operated at a sampling rate that is a non-integer multiple of the baseband sampling rate; determine a phase index of the filter impulse response as a function of a decimation rate, an interpolation rate, a starting phase index, and an output sample index of the multichannel polyphase filter; and operate the multichannel polyphase filter at the non-integer multiple of the baseband sampling rate to obtain the non-integer sampling rate change and to generate a frequency-multiplexed composite signal; and a wireless modulator for modulating a wireless carrier with the frequency-multiplexed composite signal to produce a wireless signal having M subchannels. - View Dependent Claims (16, 17)
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18. A receiver for demodulating at least two of M subchannels in parallel, wherein M is a positive integer greater than unity, the receiver comprising:
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a receiver front end for converting a wireless signal having the M subchannels into a composite signal having a sampling rate and derived from the at least two of the M subchannels; a multichannel polyphase filter coupled to the receiver front end for accepting from the receiver the composite signal and for performing a non-integer sampling rate change on the composite signal, the multichannel polyphase filter comprising; first processing means for accepting and processing the composite signal, wherein the first processing means is arranged to; provide a commutator for the multichannel polyphase filter, wherein position of the commutator is decoupled from phase of a filter impulse response selected for the position, thereby allowing the multichannel polyphase filter to be operated at a sampling rate that is a non-integer multiple of the sampling rate of the composite signal; determine a phase index of the filter impulse response as a function of M and a decimation rate, an interpolation rate, a starting phase index, a commutator position index, and an output sample index of the multichannel polyphase filter; and operate the multichannel polyphase filter at the non-integer multiple of the sampling rate of the composite signal to obtain the non-integer sampling rate change, thereby generating at least two rate-changed signals; and second processing means coupled to the multichannel polyphase filter and arranged to transform the at least two rate-changed signals into at least two frequency-domain signals, thereby generating at least two baseband signals. - View Dependent Claims (19)
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Specification