0195136047.pdf

614 ROTATING MACHINES (a) The field current is doubled, with the ar- mature terminal voltage and the load torque remaining the s ...

PROBLEMS 615 and the core-loss impedance is 400. Using the T-equivalent circuit of Figure 13.2.5(a): (a) Calculate the input cu ...

616 ROTATING MACHINES phase referred to the stator is 0.1. Neglect the stator resistance and rotational and stray-load losses. ...

PROBLEMS 617 (b) If a wye–delta starting method is employed, find the starting current and the starting torque. *13.2.22A three- ...

618 ROTATING MACHINES V has a synchronous reactance of 1.5per phase and an armature resistance of 0.5per phase. (a) Determine ...

PROBLEMS 619 chronous reactance of 2per phase and neg- ligible armature resistance. (a) If the motor takes a line current of 35 ...

620 ROTATING MACHINES 13.4.4When delivering rated load a 10-kW, 230-V self- excited shunt generator has an armature-circuit volt ...

PROBLEMS 621 (b) When the load is completely removed with- out change of excitation currents. 13.4.16The external-characteristic ...

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PART INFORMATION SYSTEMS FOUR ...

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14 Signal Processing 14.1 Signals and Spectral Analysis 14.2 Modulation, Sampling, and Multiplexing 14.3 Interference and Noise ...

626 SIGNAL PROCESSING consumption, accuracy, and reliability, digital communication systems are increasingly used for transmitti ...

14.1 SIGNALS AND SPECTRAL ANALYSIS 627 (PM) is performed primarily at the transmitter. For example, for a radio station found at ...

628 SIGNAL PROCESSING Digital message source Digital message output signal Analog message source Analog message output signal Di ...

14.1 SIGNALS AND SPECTRAL ANALYSIS 629 used, the demodulator may process the received waveform and decide on whether the transmi ...

630 SIGNAL PROCESSING Solution (a) This is a continuous-time signal (called a sinusoidal signal) that is real and periodic with ...

14.1 SIGNALS AND SPECTRAL ANALYSIS 631 xr(t) t xi(t) t |x(t)| t ∠x(t) t (b) 24 1 − 4 − 2 0 u− 1 (t) (c) 1 1 2 t x[n] (d) 2.5 2 1 ...

632 SIGNAL PROCESSING for all integersnandk, some positive integerN, and some integerm. From this it follows that 2 πf 0 kN= 2 m ...

14.1 SIGNALS AND SPECTRAL ANALYSIS 633 (b) From the sketches of Figure E14.1.1(b), forθ= 0 , x(t)=Aej^2 πf^0 t, the real part an ...