{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# hw1 - Synthesizers © 2009 G Zhang-70dBc spur-120dBc/Hz...

This preview shows pages 1–2. Sign up to view the full content.

! A LO with phase noise of -120dBc/Hz at 1MHz offset from the carrier, assume - 120dBc/Hz phase noise is uniform within 100kHz bandwidth. There is a jammer at 1MHz offset,+65dB relative to signal power(at carrier frequency). ! Question 1: after direct down conversion, how much is the down converted jammer power relative to the signal (within 100kHz base-band signal band-width); ! Question 2: in order to make the down converted jammer to be 10dB below signal, what is the max allowed phase noise at 1MHz offset; ! Question 3: if in addition to -120dBc/Hz phase noise (as in Question 1), there is also a spur at 1MHz offset with power of -70dBc, what is the down converted total jammer ECE264D Homework1, Prob#1 Page 1 power relative to signal (in 100kHz band, assume two parts of down-converted jammer power are uncorrelated). ECE264D RF Frequency

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Synthesizers © 2009 G. Zhang-70dBc spur-120dBc/Hz Q1,Q2 Q3 1MHz 65dB signal jammer ! A PLL with two forward charge-pump/loop filter paths as shown below, assume small signal linear model; ! Question1: derive the open loop transfer function, find poles and zeros; ! Question2: sketch the Bode’s plot of loop transfer: magnitude and phase (estimate with reasoning is fine, no need to be exact, assume C1 is much bigger than C2); ! Questions 3:generally C1 is too big to be integrated on chip, is there a way to reduce C1 by 10x, without changing PLL loop transfer function/bandwidth (hint, Icp1, Icp2 don’t have to be the same)? ECE264D homework1, Prob#2 UP Icp1 C1 Page 2 ECE264D RF Frequency Synthesizers © 2009 G. Zhang PFD UP/DN DN Icp1 UP DN Icp2 Icp2 + VCO Kv ideal voltage adder C2 R1 fref Div by N...
View Full Document

{[ snackBarMessage ]}

### Page1 / 2

hw1 - Synthesizers © 2009 G Zhang-70dBc spur-120dBc/Hz...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online