Delay detection circuit
AssigneeNEC Corporation
InventorSoichi Tsumura
Life of this patent
Estimating the term…
Abstract
This delay detection circuit receives a digital-phase-modulated signal including an already-known preset symbol string and an unknown data symbol string following the already-known string, and detects a phase difference between an instantaneous phase of a reception signal and an instantaneous phase after a preset symbol time from the time of the reception signal received using a phase difference detector. Then, the delay detection circuit calculates a compensation phase difference necessary to demodulate the reception signal from the phase difference, the phase difference of demodulation symbol estimated from the already-known symbol string and the phase difference of demodulation symbol estimated from the data symbol string, and demodulate the reception signal based on the compensation phase difference.
Claims15
A delay detection circuit that receives a reception signal resulting from digital-phase-modulation of an already-known symbol string and an unknown data symbol string following said already-known symbol string, comprising;
- a reception phase difference detector means for detecting a reception phase difference between an instantaneous phase of said reception signal and an instantaneous phase of another reception signal before a preset symbol time from said reception signal;
- a first compensation phase difference calculator means for calculating a first phase difference between said reception phase difference obtained at receiving said already-known symbol and an ideal phase difference of said already-known symbol and calculating a first compensation phase difference based on said reception phase difference and said first phase difference;
- a second compensation phase difference calculator means for calculating a second phase difference between said first compensation phase difference and an ideal phase difference of said unknown data symbol and calculating a second compensation phase difference based on said first compensation phase difference and said second phase difference;
- and
- a demodulation means for demodulating said reception signal based on said second compensation phase difference.
A delay detection circuit that receives a digital-phase-modulated reception signal, performs delay-detection and outputs demodulation result, comprising:
- a phase difference detector means for detecting a phase difference between a first instantaneous phase of said reception signal and a second instantaneous phase before a preset symbol time from said instantaneous phase of said reception signal;
- a plurality of dummy phase compensation quantity generator means, each dummy phase compensation quantity generator means for generating a dummy phase compensation quantity;
- a plurality of dummy phase error calculator means, each dummy phase error calculator means for adding said dummy phase compensation quantity and said phase difference and calculating a dummy phase difference;
- a plurality of dummy demodulation symbol demodulation means, each dummy demodulation symbol demodulation means for demodulating a dummy demodulation symbol based on said dummy phase difference;
- a plurality of convertor means, each convertor means for converting said dummy demodulation symbol to an ideal phase difference of said dummy demodulation symbol;
- a plurality of phase difference error calculator means, each phase difference error calculator means for calculating a phase difference error between said dummy phase difference and said ideal phase difference of said dummy demodulation symbol;
- and
- a decision means for detecting a smallest difference from phase difference errors, selecting a dummy demodulation symbol corresponding to said smallest difference from said dummy demodulation symbols, and outputting this dummy demodulation symbol as a demodulation symbol.
Dependencies are inferred from the claim text.