In multiplexed FM, we can perform further demodulation on the received message signal to obtain the...

   

 

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In multiplexed FM, we can perform further demodulation on the received message signal to obtain the various signals contained within the message signal: u(t) m(t) 0 FM Demodulation Mono Audio Left + Right 30 Hz 19kHz stereo pilot (10%) 23 15 kHz kHz Stereo Audio Left-Right Low-Pass Filter Figure 2 - In multiplexed FM, we can further demodulate the message signal The multiplexed signals are said to be modulated on subcarriers within the message signal. A typical spectrum of the FM radio signal is shown in Figure 3 below. Note that this is the spectrum of m(t), the multiplex signals contained within the message signal m(t), instead of u(t). Use this as a reference for comparison when looking at the spectrum of the demodulated received FM signal. 38 kHz Band-Pass Filter AM DSB-SC Demodulation FSK Demodulation RBDS (10%) (5%) 57 kHz DirectBand 53 kHz 58.65 kHz 67.65 kHz Mono Audio 76.65 kHz Stereo Pilot Tone Stereo Difference Audio Digital Station/Track data (RBDS) Audos subcarrier (10%) 92 99 kHz kHz Figure 3- A typical spectrum of a FM radio signal², note that DirectBand and Audos subcarrier are not used in Singapore Q2a - Given that originally the left and right audio channels are given by the terms L(t) and R(t) respectively, but the received signals are L(t) + R(t) [Mono audio Left + Right] and L(t) - R(t) [Stereo Audio Left - Right], show how the original left and right audio channels can be recovered from the received signals. Q2b - Why do you think such a method was chosen to encode the stereo audio? In multiplexed FM, we can perform further demodulation on the received message signal to obtain the various signals contained within the message signal: u(t) m(t) 0 FM Demodulation Mono Audio Left + Right 30 Hz 19kHz stereo pilot (10%) 23 15 kHz kHz Stereo Audio Left-Right Low-Pass Filter Figure 2 - In multiplexed FM, we can further demodulate the message signal The multiplexed signals are said to be modulated on subcarriers within the message signal. A typical spectrum of the FM radio signal is shown in Figure 3 below. Note that this is the spectrum of m(t), the multiplex signals contained within the message signal m(t), instead of u(t). Use this as a reference for comparison when looking at the spectrum of the demodulated received FM signal. 38 kHz Band-Pass Filter AM DSB-SC Demodulation FSK Demodulation RBDS (10%) (5%) 57 kHz DirectBand 53 kHz 58.65 kHz 67.65 kHz Mono Audio 76.65 kHz Stereo Pilot Tone Stereo Difference Audio Digital Station/Track data (RBDS) Audos subcarrier (10%) 92 99 kHz kHz Figure 3- A typical spectrum of a FM radio signal², note that DirectBand and Audos subcarrier are not used in Singapore Q2a - Given that originally the left and right audio channels are given by the terms L(t) and R(t) respectively, but the received signals are L(t) + R(t) [Mono audio Left + Right] and L(t) - R(t) [Stereo Audio Left - Right], show how the original left and right audio channels can be recovered from the received signals. Q2b - Why do you think such a method was chosen to encode the stereo audio?

Answer rating: 100% (QA)

Q2a To recover the original left and right audio channels Lt and Rt from the received signals Lt Rt and Lt Rt you can use a simple algebraic manipulat... View the full answer