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We need to transmit 100 digitized voice channels using a passband channel of 30 KHz. What should be the ratio of bits/Hz if we use no guard band?

What I understand and get the bandwidth are :

30 KHz / 100 = 300 Hz

And the ratio of bit/Hz if no guard band is 640000/300 = 213.333... bits/Hz (because digitized voice channel has a date rate of 64 Kbps)

Is that right answers?

anna
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1 Answers1

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digitization scheme. High quality PCM - 144 kbps, PCM (DSO) - 64 kbps, CVSD - 32 kbps, Compressed - 16 kbps, LPC - 2.4 kbps.

Assuming DSO, you have 100 channels at 64 kbps or 6400 kbps to send over a 20 kHz channel. Thus 6400 kbps / 20 kHZ = 320 b/Hz. Rather high packing but could be done over a noise-free channel.

Entropic multiplexing (don't send silent time) could reduce this by a factor of 5-10 for 32-64 k/HZ.

RichardBrown
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