| 摘要 |
<p>PURPOSE:To make it difficult to generate the data reproduction error caused by noise and fading, etc., by providing plural SAW filters and composing each filter so as to output a signal showing a correlation peak only when the modulation phase of an inputted signal is a corresponded modulation phase value. CONSTITUTION:On a sheet of piezoelectric substrate 1, plural SAW matched filters are composed corresponding to the number of phases of PSK. Two kinds of the input electrodes of each filter are provided by being apart with each other along a SAW propagation direction and the space of the two kinds of provided electrodes is set corresponding to any one of the phase value that a phase shift alpha(t) can take. For instance, in the case of two SAW matched filters in two-phase PSK modulation signal, the space X0 of the input electrodes 2 and 6 of a first filter is set according to a phase value alpha0 and the space X1 of the input electrodes 4 and 7 of a second filter is set according to a phase value alpha1. Namely, the correlation peak can be obtained from the first filter and the second filter when the modulation phase of the inputted PSK modulation signal is alpha0 and when the modulation phase is alpha1, respectively.</p> |
