0195136047.pdf

714 COMMUNICATION SYSTEMS ( So Nq ) = 3 L^2 KCR^2 (15.3.9) It can be seen that messages with large crest factors will lead to po ...

15.3 DIGITAL COMMUNICATION SYSTEMS 715 L≤Lb= 2 Nb (15.3.11) ifLlevels span the message variations. For example, in Figure 15.3.1 ...

716 COMMUNICATION SYSTEMS not lose track of polarity while processing polar or Manchester waveforms, a technique called differen ...

15.3 DIGITAL COMMUNICATION SYSTEMS 717 Analog message f(t) Band-limited message Presampling lowpass filter Sampler A Compressor ...

718 COMMUNICATION SYSTEMS PCM + noise Sampler Timing ≥ 0 choose 1 < 0 choose 0 VT = A^2 Tb 2 (a) Σ + − A∫ (.) dt D Tb Sampler ...

15.3 DIGITAL COMMUNICATION SYSTEMS 719 where the numeratorS 0 /Nqis given by Equation (15.3.5), or by Equation (15.3.9) when Equ ...

720 COMMUNICATION SYSTEMS .. . Σ + + f 2 (t) LPF Sampler + Compressor f 1 (t) f 2 (t) Ts Ts Ts t 2 Ts 3 Ts 3 1 1 2 (^121) Guard ...

15.3 DIGITAL COMMUNICATION SYSTEMS 721 One frame, 193 bits, 125 μs 2 3 4 5 24 One framing bit 8 bits per message word MSB LSB 1 ...

722 COMMUNICATION SYSTEMS signal transmitted from a mobile subscriber to a fixed subscriber will undergo two different types of ...

15.3 DIGITAL COMMUNICATION SYSTEMS 723 Digital recorder A/D converter Studio LR Modulator Laser recording Master disc Replicatio ...

724 COMMUNICATION SYSTEMS whereAc,ωc, andφcare the peak amplitude, angular frequency, and phase angle of the mod- ulated carrier ...

15.3 DIGITAL COMMUNICATION SYSTEMS 725 PHASE-SHIFTKEYING(PSK) In PSK, the phase angle of a carrier is keyed between two values. ...

726 COMMUNICATION SYSTEMS Sampler Sample at time Tb for bit interval 0 < t ≤ Tb Waveform formatter Channel Demodulator and co ...

15.3 DIGITAL COMMUNICATION SYSTEMS 727 t 0 Digital signal d(t) Phase of si(t) (a) (b) 0 0 π − + π Initial level 11100001 1 110 0 ...

728 COMMUNICATION SYSTEMS When Equation (15.3.23) is satisfied, the bandwidth of the channel needed to supportsFSK(t)is about 2ω ...

15.3 DIGITAL COMMUNICATION SYSTEMS 729 Pe Eb N 0 100 ASK (noncoherent) FSK (noncoherent) ASK (coherent) FSK (coherent) PCM (unip ...

730 COMMUNICATION SYSTEMS ∼=^1 2 e−^18 4. 243 √ π ∼= 1. 01 × 10 −^9 The PSK system is clearly superior to the ASK system, based ...

15.5 PRACTICAL APPLICATION: A CASE STUDY 731 Pulse-code modulation and demodulation for processing analog signals. Time-divisio ...

732 COMMUNICATION SYSTEMS The simple concept of relative phase relationships is exploited by engineers and scientists in several ...

PROBLEMS 733 15.1.16A transmitter is connected to an antenna by a transmission line for whichZ ̄ 0 =R 0 = 50 . The transmitter ...