| 摘要 |
PURPOSE:To make an optimum tuning possible to obtain an accurate tuning point by a high-speed operation, by correcting the time of deviation for generation and disapperance of respective detection signals in directions of rise and fall due to the hysteresis characteristic of a window comparator. CONSTITUTION:A frequency discriminating function which shows the detection charactersitic of an S curve is given to an FM detector 4 of the tuner of the voltage synthesizer system, and the output of this detector 4 is inputted to a window comparator 5, and detection voltages S1 and S2 are generated when the output voltage is outside a certain level range. These signals S1 and S2 are inputted to a controller 6 as signals indicating detuning signals, and an UP command, a DOWN command, and clock pulses are inputted also. This controller 6 is provided with a frequency divider which divides clocks, FFs where respective commands are stored, a reversible counter for common use and time counting, etc. to correct the time of deviation for generation and disappearance of signals S1 and S2 in directions of rise and fall due to the hysteresis characteristic, and the corrected voltage is applied to a VCO7 by a DC voltage generator to make an optimum tuning possible. |
