| 摘要 |
PURPOSE:To constitute a 3-multiple circuit with a few number of terminals by multiplying two signals with same amplitude and different phase by 90 deg. obtained from an input signal and a signal being a squared sum of said two signals. CONSTITUTION:A phase shift circuit comprising a resistor R and a capacitor C and a cosine/sine signal generating circuit 32 form two signals V1, V2 having different phase by 90 deg. from an input signal Vi. An automatic gain control loop consisting of an amplifier 33 with the unity gain, a variable gain amplifier 34 and an output comparison circuit makes the amplitude of the signals V1, V2. A logarithmic amplifier 36 squares signals V1', V2'. Then an adder circuit 37 outputs a signal V3 being the subtraction of a signal V1' by a factor 3 from a signal V2'. Then a multiplier circuit 38 multiplies the signals V3 and V2' to output an output V0 having a frequency three times that of the input signal Vi.
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