Figure 2-7. Cochannel interference

TM 11-490-5

the same frequency or channel or when the transmitters

have been assigned adjacent channels. Interference

occurs when the carrier frequency or sideband

frequency of the interferer is within the bandpass of a

victim receiver (fig 2-7 and 2-8).

Figure 2-8. Adjacent-channel interference.

(b ) Intermediate-frequency interference. A form

of interference known as intermediate frequency (IF)

Figure 2-7. Cochannel interference.

interference may occur if a high-amplitude signal at the

receiver IF reaches the mixer or IF stage (fig 2-9)

through the receiver antenna and front end, or through

the equipment case or cabling. Since the IF of a

receiver normally remains constant through the tuning

range of the receiver, this type of interference is

characterized by its presence at all tuned frequencies of

the receiver.

Figure 2-9. Intermediate-frequency interference.

2-13