Receiving apparatus for spectrum spread system
First Claim
1. A spectrum spread receiving apparatus for coherent detection scheme with interpolation using pilot symbol spectrum spread mobile communication system, comprising:
- first and second despreading circuit for despreading a received signal which is a predetermined number of bits of a digital signal oversampled by an A/D converter circuit;
a delay profile measurement instrument for averaging the profile of each chip phase of the signal despread by said first despreading circuit;
a searcher circuit for detecting a delayed waveform of a predetermined number of higher-level samples having high receiving levels from the signal output from said delay profile measurement instrument, constantly continuing to detect the predetermined number of higher-level samples, and reproducing a symbol clock signal from a position of the peak of the delayed waveform;
a delayed waveform phase determination circuit for determining whether or not the delayed waveform detected by said searcher circuit is in the same phase as the previously detected delayed waveform, and outputting a delayed waveform switch signal if the delayed waveforms are out of phase with each other; and
a demodulation circuit which, if the delayed waveform switch signal is in an ON state on the basis of the signal despread by said second despreading circuit and the delayed waveform switch signal, respectively demodulate a first half and a second half of the received signal, as a boundary is a received signal at which the delayed waveform switch signal is turned on, by using a phase estimated from a first known signal and a phase estimated from a second known signal, without interpolating the phases estimated from the first and second known signals included in both ends of an information signal.
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Accused Products
Abstract
A spectrum spread receiver is provided with a delayed waveform phase determination circuit which determines whether or not a detected delayed waveform is in the phase as the previously-detected delayed waveform, and outputs a delayed waveform switch signal if they are out of phase with each other. If the delayed waveform switch signal is in an ON state, on the basis of the signal despread by a second despreading circuit 7 and the delayed waveform switch signal, a demodulation circuit 9 demodulates the first half and second half of a received signal, as a boundary is a received signal at which a delayed waveform switch signal is turned on, by using the phase estimated from a first known signal and the phase estimated from a second known signal, thereby preventing the received signal from becoming degraded.
25 Citations
4 Claims
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1. A spectrum spread receiving apparatus for coherent detection scheme with interpolation using pilot symbol spectrum spread mobile communication system, comprising:
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first and second despreading circuit for despreading a received signal which is a predetermined number of bits of a digital signal oversampled by an A/D converter circuit; a delay profile measurement instrument for averaging the profile of each chip phase of the signal despread by said first despreading circuit; a searcher circuit for detecting a delayed waveform of a predetermined number of higher-level samples having high receiving levels from the signal output from said delay profile measurement instrument, constantly continuing to detect the predetermined number of higher-level samples, and reproducing a symbol clock signal from a position of the peak of the delayed waveform; a delayed waveform phase determination circuit for determining whether or not the delayed waveform detected by said searcher circuit is in the same phase as the previously detected delayed waveform, and outputting a delayed waveform switch signal if the delayed waveforms are out of phase with each other; and a demodulation circuit which, if the delayed waveform switch signal is in an ON state on the basis of the signal despread by said second despreading circuit and the delayed waveform switch signal, respectively demodulate a first half and a second half of the received signal, as a boundary is a received signal at which the delayed waveform switch signal is turned on, by using a phase estimated from a first known signal and a phase estimated from a second known signal, without interpolating the phases estimated from the first and second known signals included in both ends of an information signal. - View Dependent Claims (2, 3, 4)
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Specification