| 摘要 |
PURPOSE:To demodulate an information signal without deteriorating a steady- state tracking characteristic by providing a low pass filter tracing a steady-state phase change and a band pass filter tracking a momentary phase change in parallel as a loop filter to the lock loop. CONSTITUTION:A pseudo noise(PN) signal sent from a transmitter is given to a receiver, in which the signal is extracted as a demodulation signal based on the correlation of the received PN code through the use of a multi-filter delay lock loop including a correlation network via an RF amplifier section 1 and a frequency converter 2. The delay lock loop consists of two filters provided in parallel, that is, a low pass filter 6 and a band pass filter 7. Since the low pass filter 6 relates to a steady-state tracking characteristic, the cut-off frequency is set in the vicinity of the DC component such as 2-3kHz and the center frequency of the band pass filter 7 depends on the frequency of the information signal and the band width is sufficient to extract the information signal. |
