Apparatus for measuring frequency error of CDMA signals
OwnerMitsuru Yokoyamainventor
Life of this patent
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Abstract
Phase error signals are detected at the symbol evaluation point of signals under test that have been receiver filter-processed, and reference signals obtained by remodulation and respreading of bit data restored from the filter-processed signals under test, or signals obtained by differentiating said phase error signals are calculated, and either of these are displayed as a graph over the period of time when they have a length exceeding one slot.
Claims16
An apparatus for measuring the frequency error of digital modulation signals from a CDMA system whereby data are transmitted and received in slot units, including the pilot signals for each slot, or a CDMA system whereby data are transmitted and received in slot units using common pilot signals, said apparatus comprising:
- a reference signal generator for remodulation and respreading of bit data obtained by de-spreading and demodulation of said digital modulation signals using the modulation parameters and spreading parameters that are used when said digital modulation signals are generated, and outputting the resulting signals as reference signals;
- a comparator for comparing said digital modulation signals and said reference signals and generating phase error signals that represent the phase error at each symbol evaluation point of the digital modulation signals with respect to said reference signals;
- and
- a differentiator for calculating the gradient of said phase error signals for each of multiple intervals shorter than the slot length of said digital modulation signals,
- wherein each of the multiple intervals is lined up in a time series adjacent to one another or partially overlapping one another and the overall length is longer than one slot.
An apparatus for measuring the phase error of digital modulation signals from a CDMA system whereby data are transmitted and received in slot units, including the pilot signals for each slot, or a CDMA system whereby data are transmitted and received in slot units using common pilot signals, said apparatus comprising:
- a reference signal generator for remodulation and respreading of bit data obtained by de-spreading and demodulation of said digital modulation signals using the modulation parameters and spreading parameters that are used when said digital modulation signals are generated, and outputting the resulting signals as reference signals;
- and
- a comparator for comparing said digital modulation signals and said reference signals and generating phase error signals that represent the phase error at each symbol evaluation point of the digital modulation signals with respect to said reference signals.
A method for measuring the frequency error of digital modulation signals from a CDMA system whereby data are transmitted and received in slot units, including the pilot signals for each slot, or a CDMA system whereby data are transmitted and received in slot units using common pilot signals, said method comprising:
- remodulating and respreading of bit data obtained by de-spreading and demodulation of said digital modulation signals using the modulation parameters and spreading parameters that are used when said digital modulation signals are generated, and outputting the resulting signals as reference signals;
- comparing said digital modulation signals and said reference signals and generating phase error signals that represent the phase error at each symbol evaluation point of the digital modulation signals with respect to said reference signals;
- and
- calculating the gradient of said phase error signals for each of multiple intervals shorter than the slot length of said digital modulation signals,
- outputting the calculation results,
- wherein each of the multiple intervals are lined up in a time series adjacent to one another or partially overlapping one another and the overall length is longer than one slot.
A method for measuring the phase error of digital modulation signals from a CDMA system whereby data are transmitted and received in slot units, including the pilot signals for each slot, or a CDMA system whereby data are transmitted and received in slot units using common pilot signals, said method comprising:
- remodulating and respreading of bit data obtained by de-spreading and demodulation of said digital modulation signals using the modulation parameters and spreading parameters that are used when said digital modulation signals are generated, and outputting the resulting signals as reference signals;
- and
- comparing said digital modulation signals and said reference signals and generating phase error signals that represent the phase error at each symbol evaluation point of the digital modulation signals with respect to said reference signals;
- thereby measuring the phase error of said digital modulation signals.
Dependencies are inferred from the claim text.