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Learn about symbol clock recovery for PAM systems, including prefiltering, squaring, and bandpass filters. Design and implement filters using fdatool and lab code.
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EE 445S Real-Time Digital Signal Processing LabFall 2013 Lab #5.2PAM Symbol Clock RecoveryChao Jia
Outline • Recap: The Symbol Clock Recovery Block in the Receiver. • Symbol Clock Recovery: Step by Step.
Symbol Clock Recovery: Recap • In PAM systems, the receiver has no perfect knowledge of the transmitter’s symbol clock frequency • The symbol clock recovery module is used to recover the transmitter’s symbol frequency.
Symbol Clock Recovery: Prefiltering Recall from last time: If we define g(t) to be equal to: Then the output of the receive filter is:
Symbol Clock Recovery: Prefiltering & Squaring Under the assumption of no additive noise in the channel:
Symbol Clock Recovery: Squaring Fourier Series Expansion
Symbol Clock Recovery: Bandpass and PLL • : a bandpass filter centered half of the symbol rate. Then except for k = -1,0,1 • : a bandpass filter centered at the symbol rate.Then except for k=-1,1 • is a sinusoid signal at the symbol clock frequency. is a sinusoid with a slowly varying amplitude and phase • Design the two filters using fdatool and implement them using code in lab3 (biquads)
