| 摘要 |
PURPOSE:To obtain an oscillating circuit which does not require many oscillation sources and has a variable frequency and is stably operated, by converting the frequency signal from a logic circuit, which converts the output frequency signal from the second oscillation source, to an analog signal to modulate the output frequency signal from the first oscillation source. CONSTITUTION:One part of the signal oscillated by a highly stable oscillation source 1 is inputted to one multiplier 2, and another part is inputted to the other multiplier 4 through a 90 deg. phase shifter 3, and outputs of multipliers 2 and 4 are subjected to subtraction by an adder 5. The frequency signal oscillated by an oscillation source 6 which is highly stable similarly to the oscillation source 1 is converted to frequency signals different in phase by 90 deg. by a logic circuit 7, and they are converted to digital signals by A/D converters 8 and 9 and are integrated by filters 10 and 11 and are inputted to multipliers 2 and 4. Thus, the frequency of an output Vout can be changed in a wide range if the oscillation frequency of the oscillation source 6 is converted to another frequency by the logic circuit 7, and the output signal is stabilized because highly stable oscillation sources 1 and 6 are used.
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