| 摘要 |
In a discriminator that utilizes one or more piezoelectric crystals, the crystals are tuned to resonate at a desired frequency after being connected in the discriminator, since the capacity of the discriminator components is not determinable prior to being used. The tuning includes frequency modulating a carrier signal of the desired frequency with a selected sinusoidal signal, and applying this frequency-modulated signal to the discriminator. Each crystal is then respectively tuned (such as by plating) to resonate at the desired frequency. Resonance is indicated when the discriminator output signal is approximately twice the sinusoidal modulating frequency.
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