Question 2.9: For a tribit input of Q = 0, I = 0, and C = 0 (000), determi......

For a tribit input of Q = 0, I = 0, and C = 0 (000), determine the output amplitude and phase for the 8-QAM transmitter shown in Figure 30a.

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The inputs to the I channel 2-to-4-level converter are I = 0 and C = 0. From Figure 30b, the output is -0.541 V. The inputs to the Q channel 2-to-4-level converter are Q = 0 and C = 0. Again from Figure 30b, the output is -0.541 V.

Thus, the two inputs to the I channel product modulator are -0.541 and sin $ω_{c}t$. The output is

I = (-0.541)(sin $ω_{c}t$) = -0.541 sin $ω_{c}t$

The two inputs to the Q channel product modulator are -0.541 and cos $ω_{c}t$. The output is

Q = (-0.541)(cos $ω_{c}t$) = -0.541 cos $ω_{c}t$

The outputs from the I and Q channel product modulators are combined in the linear summer and produce a modulated output of

summer output = -0.541 sin $ω_{c}t$ -0.541 cos $ω_{c}t$
= 0.765 sin($ω_{c}t$ – 135°)

For the remaining tribit codes (001, 010, 011, 100, 101, 110, and 111), the procedure is the same. The results are shown in Figure 31.
Figure 32 shows the output phase-versus-time relationship for an 8-QAM modulator. Note that there are two output amplitudes, and only four phases are possible.

Question: 2.15

For a QPSK system and the given parameters, determine a. Carrier power in dBm. b. Noise power in dBm. c. Noise power density in dBm. d. Energy per bit in dBJ. e. Carrier-to-noise power ratio in dB. f. Eb/N0 ratio. C = 10^-12 W fb = 60 kbps N = 1.2 × 10^-14 W B = 120 kHz ...

a.  The carrier power in dBm is determined by subs...
Question: 2.13

For an 8-PSK system, operating with an information bit rate of 24 kbps, determine (a) baud, (b) minimum bandwidth, and (c) bandwidth efficiency. ...

a.  Baud is determined by substituting into Equati...
Question: 2.11

For a 16-QAM modulator with an input data rate (fb) equal to 10 Mbps and a carrier frequency of 70 MHz, determine the minimum double-sided Nyquist frequency (fN) and the baud. Also, compare the results with those achieved with the BPSK, QPSK, and 8-PSK modulators in Examples 4, 6, and 8. Use the 16 ...

The bit rate in the I, I′ , Q, and Q′ channels is ...
Question: 2.10

For a quadbit input of I = 0, I′ = 0, Q = 0, and Q′ = 0 (0000), determine the output amplitude and phase for the 16-QAM modulator shown in Figure 33. ...

The inputs to the I channel 2-to-4-level converter...
Question: 2.8

For an 8-PSK modulator with an input data rate (fb) equal to 10 Mbps and a carrier frequency of 70 MHz, determine the minimum double-sided Nyquist bandwidth (fN) and the baud. Also, compare the results with those achieved with the BPSK and QPSK modulators in Examples 4 and 6. Use the 8-PSK block ...

The bit rate in the I, Q, and C channels is equal ...
Question: 2.5

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For a binary data input of Q = 0 and I = 0, the tw...
Question: 2.7

For a tribit input of Q = 0, I = 0, and C = 0 (000), determine the output phase for the 8-PSK modulator shown in Figure 23. ...

The inputs to the I channel 2-to-4-level converter...
Question: 2.6

For a QPSK modulator with an input data rate (fb) equal to 10 Mbps and a carrier frequency of 70 MHz, determine the minimum double-sided Nyquist bandwidth (fN) and the baud. Also, compare the results with those achieved with the BPSK modulator in Example 4. Use the QPSK block diagram shown in ...

The bit rate in both the I and Q channels is equal...
Question: 2.17

Which system requires the highest Eb/N0 ratio for a probability of error of 10^-6, a four-level QAM system or an 8-PSK system? ...

From Figure 49, the minimum E_{b}/N_{0}[/la...
From Figure 48, the minimum E_{b}/N_{0}[/la...