q what do you mean by fm stereoit shows the

Question

Q. What do you mean by FM Stereo?

IT  shows the block diagram of an FM stereo transmitter and an FM stereo receiver. The following notation is used:

• f_L(t), fR(t): Left and right messages that undergo preemphasis and are then added to yield f 1(t) and differenced to give fd(t).

• f₂(t): Given by signal fd(t) when it DSB-modulates (with carrier suppressed) a 38-kHz subcarrier.

• f₃(t):Alow-level pilot carrier at 19 kHz that is included to aid in the receiver's demodulation process.

• f_s(t): Final compositemessagewhen f₁(t), f₂(t), f₃(t), and SCA(subsidiary communications authorization) are all added up.

• SCA: A narrow-band FM waveform on a 67-kHz subcarrier with a total bandwidth of 16 kHz. It is a special signal available to fee-paying customers who may desire to have background music free of commercials or nonaudio purposes such as paging.

• NBPF: Narrow-band band-pass filter.

• LPF, BPF, and NBPF: Appropriate filters that select the spectrum portions corresponding to f₁(t), f₂(t), and f₃(t), respectively.

The output signal-to-noise power ratio is smaller in FM stereo than in a monaural system with the same transmitted power, messages, and other parameters. With a loss as high as 22 dB, many FM stations can tolerate the loss because of the high power being transmitted.