Lecture 4 – Sampling theorem and types of sampling

Örneklenmiş işaret (Dirac katarı ile)

f_s<2f_m olursa Örtüşme (Aliasing)

Pratikte x(t) zamanda sınırlı, frekansta sınırlı değil (not band limited)

Çözüm: Örtüşme engelleyici filtre

Anti-aliasing filter

İşareti yeniden oluşturma

Üçgen varsa linear interpolasyon

varsa kare darbelerle temsil edilir

(yeniden oluşturma denklemi) Reconstruction eq

(İdeal interpolasyon //) ideal interpolation

A signal x(t)=sinc^2(5t) is sampled (using uniformly spaced impulses) at a rate of:

For each of three cases

a) Sketch the sampled signal

b) Sketch the spectrum of the sampled signal

c) Explain whether you can recover the signal x(t) from the sampled signal

d) If the sampled signal is passed through an ideal LPF of BW 5 Hz, Sketch the spectrum of the output signal.

Darbe Genlik mod. (DGM) deniliyor ama bu değil!!! sonra

Pulse amplitude mod (PAM)

A signal x(t) band limited to B Hz is sampled by a periodic pulse train p_T_s(t) made up of a rectangular pulse of width 18B seconds (centered at the origin) repeating at the Nyquist rate ( 2B pulses per second). Show that the sampled signal x_s(t) is given by

Show that the signal x(t) can be recovered by passing x_s(t) through an ideal LPF of BW B Hz and a gain of 4.

böyle olduğunu ispatlamamız gerek

Düz Tepeli örnekleme

(Flat top sampling) (FTS)

tepeyi takip etmiyor

Sample and hold circuit

(Örnekle ve tut devresi)

x_s(t) : Darbe Genlik mod (DGM)

Pulse amplitude mod