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edit approved Jan 8, 2016 at 16:27
Tomislav Nakic-Alfirevic
edit approved Jan 8, 2016 at 16:27
Tomislav Nakic-Alfirevic
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One Question of my note is like this.

Consider a communication channel with a bandwidth of 2400Hz. If QPSK technique is
used, what is the possible transmission rate? (Assume that rectangular  
pulses are used in
  the baseband signals, and that 90% energy preservation is  
required.)

For a baseband system, a bipolar signal of bandwidth B can support a rate of B  
with 90%
  energy preservation (since bandwidth =1/τ in this case).
For a bandpass system, a BPSK signal of bandwidth of B can support a rate of B/2. This
This is because, after modulation, the bandwidth is 2/τ.
For QPSK, rate can be doubled using the same bandwidth. Therefore the  
supported rate is
  2400bps.

Why the BPSK signal of bandwidth 2/τ can support a datarate of B/2? and what is the relationship between the bandwidth and the datarate? and why in the QPSK, the rate can be doubled using the same bandwidth?

One Question of my note is like this.

Consider a communication channel with a bandwidth of 2400Hz. If QPSK technique is
used, what is the possible transmission rate? (Assume that rectangular pulses are used in
 the baseband signals, and that 90% energy preservation is required.)

For a baseband system, a bipolar signal of bandwidth B can support a rate of B with 90%
 energy preservation (since bandwidth =1/τ in this case).
For a bandpass system, a BPSK signal of bandwidth of B can support a rate of B/2. This
is because, after modulation, the bandwidth is 2/τ.
For QPSK, rate can be doubled using the same bandwidth. Therefore the supported rate is
 2400bps.

Why the BPSK signal of bandwidth 2/τ can support a datarate of B/2? and what is the relationship between the bandwidth and the datarate? and why in the QPSK, the rate can be doubled using the same bandwidth?

One Question of my note is like this.

Consider a communication channel with a bandwidth of 2400Hz. If QPSK technique is
used, what is the possible transmission rate? (Assume that rectangular 
pulses are used in the baseband signals, and that 90% energy preservation is 
required.)

For a baseband system, a bipolar signal of bandwidth B can support a rate of B 
with 90% energy preservation (since bandwidth =1/τ in this case).
For a bandpass system, a BPSK signal of bandwidth of B can support a rate of B/2.
This is because, after modulation, the bandwidth is 2/τ.
For QPSK, rate can be doubled using the same bandwidth. Therefore the 
supported rate is 2400bps.

Why the BPSK signal of bandwidth 2/τ can support a datarate of B/2? and what is the relationship between the bandwidth and the datarate? and why in the QPSK, the rate can be doubled using the same bandwidth?

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Samuel
Samuel
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the relationship between bandwidth and the datarate

One Question of my note is like this.

Consider a communication channel with a bandwidth of 2400Hz. If QPSK technique is
used, what is the possible transmission rate? (Assume that rectangular pulses are used in
the baseband signals, and that 90% energy preservation is required.)

For a baseband system, a bipolar signal of bandwidth B can support a rate of B with 90%
energy preservation (since bandwidth =1/τ in this case).
For a bandpass system, a BPSK signal of bandwidth of B can support a rate of B/2. This
is because, after modulation, the bandwidth is 2/τ.
For QPSK, rate can be doubled using the same bandwidth. Therefore the supported rate is
2400bps.

Why the BPSK signal of bandwidth 2/τ can support a datarate of B/2? and what is the relationship between the bandwidth and the datarate? and why in the QPSK, the rate can be doubled using the same bandwidth?