| 摘要 |
PURPOSE:To facilitate line connection, line monitor, etc., by amplifying the DC component of a low pass filter by a DC gain variable amplifier controlled with a frequency division ratio designating signal to fix the output frequency switching time when the output frequency is changed at intervals of a comparison frequency. CONSTITUTION:An oscillation frequency is divided into three bands, and their center frequencies are defined as f1, f0, and f2 in order from the lowest frequency, and loop gains corresponding to them are defined as GL1, GL0, and GL2, and an optimum loop gain is defined as GL0. For the purpose of equalizing loop gains of frequencies f1, f0, and f2, it is sufficient if the loop gain is made lower by GL1-GL0 in case of the frequency f1 and the loop gain is made higher by GL0-GL2 in case of the frequency f2. When a DC gain variable amplifier 5' controlled by a frequency division ratio designating signal S1 is set to such value that the loop gain is GL0 in case of the frequency f0, loop gains of frequencies f1, f0, and f2 are equalized if the gain of the DC gain variable amplifier 5' is made lower by GL1-GL0 in case of the frequency f1 and is made higher by GL0-GL2 in case of the frequency f2. |
