07-10-2013, 12:47 PM
'Zero-beat' traditionally refers to the audio product of two RF carriers together, with the difference between them showing up as a tone or whistle through some sort of detector and reproducer (speaker or headphones).
The closer they are together, frequency-wise, the lower the tone. You will find there is a null in between the lowering and raising tone.
When the tone finally gets past slow to no sound, it is said to be at 'zero-beat'.
Your FM radio probably has some sort of AFC, or automatic frequency control. It will tend to make nulling a bit more difficult, hence the instruction to keep an eye on levels and not let that function affect your test.
Dennis
The closer they are together, frequency-wise, the lower the tone. You will find there is a null in between the lowering and raising tone.
When the tone finally gets past slow to no sound, it is said to be at 'zero-beat'.
Your FM radio probably has some sort of AFC, or automatic frequency control. It will tend to make nulling a bit more difficult, hence the instruction to keep an eye on levels and not let that function affect your test.
Dennis
Pacing the cage...
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