Abstract: The position of a specific pattern such as a known symbol in a signal such as an OFDM signal is estimated with high accuracy. An effective symbol extraction section extracts a known symbol (preamble) as an effective symbol from a signal to be measured according to an approximate position of the known symbol. A mixer determines the product of the frequency spectrum of the extracted effective symbol by the result of the conversion performed by a complex conjugate conversion section from the frequency spectrum of the known symbol into the conjugate complex. A phase shift amount measuring section measures the phase shift amount ?? of the product determined by the mixer. A precision pattern position measuring section measures the difference between the position of the known symbol and its approximate position on the basis of the phase shift amount.

Abstract: The symbol points of a received signal can be more precisely measured.

Abstract: The position of a specific pattern such as known symbol in a signal such as an OFDM signal is estimated with high accuracy. An effective symbol extraction section (12) extracts a known symbol (preamble) as an effective symbol from a signal to be measured according to an approximate position of the known symbol. A mixer (20) determines the product of the frequency spectrum of the extracted effective symbol by the result of the conversion performed by a complex conjugate conversion section (16) from the frequency spectrum of the known symbol into the conjugate complex. A phase shift amount measuring section (26) measures the phase shift amount ?? of the product determined by the mixer (20). A precision pattern position measuring section (28) measures the difference between the position of the known symbol and its approximate position on the basis of the phase shift amount.

Abstract: In a measurement of a quality of a CDMA signal diffused by a long code and a short code, the measurement can be performed even if a carrier frequency error is relatively large. A received signal is converted to a complex base band signal s (12) and a symbol point of the signal extracted (33). A frequency error &Dgr;f is obtained from a phase slippage from the signal point (34). The signal s is corrected by the &Dgr;f and the corrected signal s′ is decoded by a diffusion signal of each channel. Also each power is obtained and each reference signal is created. A delay time &tgr; is obtained from each reference signal and the signal s′ such that a square error &egr; between them is minimized (37). The signal s′ is corrected by the value &tgr;. Regarding the corrected signal s″ thereof, a frequency error and an initial phase are obtained such that &egr; is minimized (38). The signal s″ is corrected by those frequency error and initial phase to generate a signal s′″.

Abstract: A complex base band signal b of a send signal from a mobile station of the CDMA system is obtained, then a portion of the complex base band signal is normalized in amplitude, and the normalized signal is synchronized with a PN code and the time reference is estimated. A frequency error is estimated from a complex correlation value used for the estimation of the time reference. The normalized signal is corrected corresponding to the estimated frequency error, and the corrected signal is used to estimate and correct the initial phase. The corrected signal and the time reference are used to estimate a time lag between a symbol point and the sample point nearest thereto and a reference signal displaced by the time lag is generated. The reference signal and the corrected signal are used to estimate the remaining frequency error and initial phase by the least squares method.

Abstract: An input quadrature modulation signal which is converted into a digital signal is converted into a complex baseband signal in a converter 7. A rough estimation of parameters of the signal is made in a rough signal correction unit 51. Using the estimates, the complex baseband signal is corrected. Utilizing a data detection of the corrected signal, a reference signal which corresponds to a transmitted signal is formed from the detected data in a generator 52. The reference signal and the corrected signal are used to estimate parameters in a fine parameter estimation unit 23.

Abstract: The signal to be measured is converted into digital form and read into a memory 13 using a trigger as the reference, and a signal of a length 1/5 that of the signal to be measured, in the vicinity of the trigger, is orthogonal-transformed (14). A frequency error .omega..sub.1 of the transformed output I.sub.1,Q.sub.1 is estimated (15) and is used to correct the output I.sub.I, Q.sub.I (16). The corrected output I.sub.2,Q.sub.2 is subjected to processing by a receiving filter (17), and the filtered output I.sub.3,Q.sub.3 is synchronized with a PN code to obtain an ideal signal R.sub.I,R.sub.Q and a phase difference .tau..sub.1 is calculated. The signal I.sub.3,Q.sub.3 and the ideal signal R.sub.I,R.sub.Q are used to obtain a frequency error .omega..sub.2 and a phase error .tau..sub.2 of the signal I.sub.3,Q.sub.3. All signals to be measured, stored in the memory 13, are subjected to orthogonal transformation (23) so that the frequency error .omega..sub.1 +.omega..sub.2 and the phase error .tau..sub.1 +.tau..