4-28
V0
Filter
V1V2
Trigonometric identities: sin(x)sin(y) = ½cos(x-y) - ½cos(x+y)
cos(x±p/2) = sin(x)
•  Phase detector:
•
•
•  AM detector:
•
•
•   Frequency multiplier:
•
•
When V1 = V2 and the filter is bandpass at 2w1
Mixer Functions
   A mixer is a versatile device in frequency metrology.  As shown above, the input to the mixer are two voltages, and the output is the product of those voltages.  Through the application of elementary trigonometry, a mixer can be made into a phase detector, an amplitude detector, and a frequency multiplier.


P. Kartaschoff, Frequency and Time, section 3.4 “Frequency Multiplication and Division,” Academic Press, 1978.