Module IIITaub Ch.6 презентация

Содержание

1. Module IIITaub Ch.6
2. Examples of Modulation Amplitude Shift Keying (ASK)
3. Description of binary ASK,PSK, and FSK
4. Binary information over bandpass channels
5. Digital modulation and channel
6. Digital Demodulator
7. Signal Regeneration
8. Bandwidth of signal Baseband versus bandpass:
9. BPSK-Transmitter
10. Scheme to recover the baseband signal in BPSK
11. BPSK-Receiver
12. Cont..
13. Spectrum of BPSK
14. PSD of NRZ data b(t) & binary PSK
15. Geometrical Representation of BPSK Signals
16. Differential Phase-Shift Keying Merit – it eliminate
17. Means of generating a DPSK signal
18. Logic waveforms to illustrate the response b(t) to an input d(t)
19. Method of recovering data from the DPSK signal
20. Cont.. The transmitted data d(t) can be
21. Type-D flip-flop
22. Quadrature Phase-Shift Keying (QPSK) BW for BPSK
23. An offset QPSK Transmitter
24. Waveforms for the QPSK Transmitter
25. OQPSK
26. Phasor diagram for sinusoids in QPSK Transmitter
27. A QPSK Receiver Carrier Recovery Circuit
28. Signal Space Representation
29. The four QPSK signal drawn in signal space 2 2
30. M-ary PSK
31. Geometrical representation of M-ary PSK signals
32. Cont..
33. Cont..
34. M-ary PSK Transmitter
35. M-ary PSK receiver
36. BFSK
37. BFSK signal generator
38. Spectrum of BFSK
39. The PSD of individual terms
40. A BFSK Receiver
41. Geometrical Representation of Orthogonal BFSK
42. Signal space representation orthogonal / non-orthogonal
43. An M-ary Communication System
44. M-ary FSK
45. Power Spectral Density of M-ary FSK (four frequencies)
46. Geometrical Representation of orthogonal M-ary FSK (M=3)
47. MSK

Examples of Modulation Amplitude Shift Keying (ASK) or On/Off Keying (OOK): Frequency Shift Keying (FSK): Phase Shift Keying (PSK):

Слайд 1Module III Taub Ch.6
PSK
QPSK
M-ary PSK
FSK
M-ary FSK
MSK

Слайд 2Examples of Modulation
Amplitude Shift Keying (ASK) or On/Off Keying (OOK):

Frequency Shift

Keying (FSK):

Phase Shift Keying (PSK):

Слайд 3
Description of binary ASK,PSK, and
FSK schemes
Bandpass binary data transmission

system

Modulator

Channel
Hc(f)

Demodulator
(receiver)

{bk}

Binary
data

Input

{bk}

Transmit
carrier

Clock pulses

Noise
n(t)

Clock pulses

Local carrier

Binary data output

Z(t)

V(t)

ּ+

Слайд 4Binary information over bandpass channels

Слайд 5Digital modulation and channel

Слайд 6Digital Demodulator

Слайд 7Signal Regeneration

Слайд 8Bandwidth of signal

Baseband versus bandpass:

Слайд 9BPSK-Transmitter

Слайд 10Scheme to recover the baseband signal in BPSK

Слайд 13Spectrum of BPSK

Слайд 14PSD of NRZ data b(t) & binary PSK

Слайд 15Geometrical Representation of BPSK Signals

Слайд 16Differential Phase-Shift Keying
Merit – it eliminate the ambiguity about whether the

demodulated data is or is not inverted.
Avoids the need to provide the synchronous carrier required at the demodulator for detecting a BPSK signal.
Arbitrarily assuming that in the first interval b(0)=0. In the demodulator, the data will be correctly determined regardless of our assumption concerning b(0) - Invariant feature of the system.
i.e no change in b(t) occur whenever d(t)=0, and a change in b(t) occurs whenever d(t)=1.
When d(t)=0 the phase of the carrier does not change at the beginning of the bit interval, while when d(t)=1 there is a phase change of magnitude π.

Слайд 17Means of generating a DPSK signal

Слайд 18Logic waveforms to illustrate the response b(t) to an input d(t)

Слайд 19Method of recovering data from the DPSK signal

Слайд 20Cont..
The transmitted data d(t) can be readily determined from the product

b(t)b(t-Tb).
If d(t)=0 then there was no phase change and b(t)=b(t-Tb) both being +1V or both being -1V. In this case b(t)b(t-Tb)=1.
If however d(t)=1 then there was a phase change and either b(t)=1V with b(t-Tb)= -1V or vice versa.
In either case b(t)b(t-Tb)= -1.