EMC and Transmitter Interference
Cross Modulation & Blocking
- When a strong signal overloads an amplifier it can cause the gain of the amplifier
to vary in time with its modulation, imposing its modulation on a wanted AM signal,
e.g., TV video, as light and dark horizontal lines; lesser impact on FM signals
- SSB is worst for this; interference from FM transmissions might go unnoticed
- A strong signal may affect the receiver’s AGC circuits, or overload an amplifier stage,
turning down gain and causing the wanted signal to become weak or / and noisy;
this is known as desensing or blocking
- It is more common from FM or data modes