| 摘要 |
A radio receiver such that even though the variations of elements are large, the receiving condition can be set the same irrespective of the antenna input level. In the receiver, a high-frequency cut-off circuit (30) removes a high-frequency band included in a composite signal according to a high-frequency cut-off factor and according to the voltage applied to an HCC terminal (30a). The main signal and the sub-signal which are included in the composite signal are demodulated respectively by main demodulation and sub-demodulation circuits (32, 34). In the sub-demodulation circuit (34), based on the voltage applied to an SPC terminal (34a), the demodulation level of the sub-signal is changed from 0 to 100 % according to its separation characteristic to control the separation. From the demodulated main signal and sub-signal, a matrix circuit (36) reproduces L and R signals and outputs them. A signal meter output voltage from an FM detection IC (12) is inputted to a microcomputer (20). In an operation part (24), based on the signal meter output reference voltage and a control reference voltage which are stored in an EEPROM (18), the intrinsic signal meter output voltage of the receiver is corrected, and the SPC and HCC voltages, which have no variation due to differences in antenna input level even though the antenna input level changes are calculated to be applied to the HCC and SPC terminals (30a, 34a).
|
