| 摘要 |
A testing method or apparatus utilizes multiple frequencies applied to a device under test for measuring newly discovered frequency modulation effects. An embodiment may include a lower frequency signal with a smaller amplitude higher frequency signal to test a dynamic change in frequency response, gain, and or phase. This dynamic test can reveal frequency modulation effects. Another embodiment may include the use of a multiple frequency signal or a modulated signal such as an amplitude modulated to dynamically induce a time varying phase or frequency distortion for the device that has differential phase distortion. In another embodiment, the device's output is then measured with an FM detector, Wow and/or Flutter meter, phase detector, and or spectrum analysis system to measure a shift in one of the frequencies used in the test signal or to measure phase and or frequency modulation effects of any signals such as a distortion product, a carrier signal, and or a distortion product of the carrier signal from the device. |
