| 摘要 |
PURPOSE:To obtain a code identification circuit not susceptible to the adverse effect due to temperature even in using a conventional resonance circuit by adopting the constitution that a phase shift of a phase shift circuit optimizing the sample timing of an A/D conversion circuit is controlled by using a phase difference output signal. CONSTITUTION:Even when the characteristic of the 1st resonance circuit 6 is fluctuated due to ambient temperature change and the phase of an extracted clock signal changes, the characteristic of the 2nd resonance circuit 9 is changed similarly as that of the resonance circuit 6. Then a phase error proportional to the temperature characteristic of the resonance circuit appears at the output of a phase comparison circuit 8. In giving a phase change of opposite polarity corresponding to the phase error by a phase shift circuit 10, the phase change of the resonance circuit 6 due to its temperature characteristic is cancelled. Thus, the sample timing of the A/D conversion circuit 2 is always kept constant against the ambient temperature change.
|
