Transcript No Slide Title

Semiconductor
Simulation
Laboratory
Phase-Locked Loop Design
Phase-Locked Loops
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Phase-locked loops: Building blocks in receivers and
other communication electronics
Main premise: Lock in to a frequency or phase
component of an incoming signal and give a
synchronized output
Block diagram:
Phase Detector & Loop Filter: Schematic and Responses
•Phase Detector: Creates an output proportional to the
phase difference between its input signals, the incoming data
and the feedback signal.
•Loop Filter: A low pass filter; adds another pole to the
feedback loop to control lock-in range and frequency.
•Voltage-Controlled Oscillator: Produces a clock signal
whose frequency is proportional to its input voltage.
•Divide-by-N Counter: Feeds the output clock signal, its
frequency divided by N, back to the PD.
•Closed Loop Gain:
H ( s) 
 clock
K PD KVCO K F

 data s  1 K K K
PD VCO F
N
Phase detector and the loop filter
Transient responses for the phase detector and the loop filter
VCO Current Pump and the VCO: Schematic and Responses
10-bit Counter Schematics
Design Specifications
•Design Goal Given a reference clock signal at 200 kHz,
design a PLL whose output will oscillate in a range between
110 MHz to 130 MHz.
•For the block diagram above, this requires a divide-by-N
counter with N between 550 and 650.
•Therefore we used a 10-bit binary downcounter. The inputs
set the number it starts counting down from. The output of the
VCO is the “count” signal for the counter. When the counter
reaches zero, it is reloaded and sends a pulse to the phase
detector.
Full VCO
A VCO current pump
250
VCO_f (MHz)
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Circuit Operation
200
150
100
50
0.9 0.95
1
1.05 1.1 1.15 1.2 1.25 1.3
Vin (V)
Phase-Locked Loop, Complete Circuit
VCO current pump, current vs. Vin
VCO, input voltage vs. frequency
Phase-Locked Loop, Operation: Simulation Results
Reference Clock and the Counter Output
PD output to loop filter and loop filter output to VCO
VCO outputs at the beginning of the simulation
and after lock-in
A High-Frequency FM Transceiver
Transmitter PC Board Design
FM Transceiver: Frequency-Modulation Transmitter and Receiver
A FM transceiver consists both FM transmitter and FM receiver where FM stands for “frequency modulation”. Transmitter and receiver
are the basic building blocks in modern wireless communication systems. A transmitter modulates the information signal and transmits the
modulated signal in form of electro-magnetic wave. A receiver, on the other hand, receives this modulated signal and demodulates it in which
way the original information is recovered. Frequency modulation differs from amplitude modulation by reflecting the changing of the amplitude
of the information signal to the frequency domain. The superheterodyne topology is used for high frequency solution.
We are working on the design and hardware implementation of a high-frequency FM transceiver. First, we try to investigate some of the
design issues and thus improve the performance of the system. Second, we use this transmitter as the platform to test signal interference effects
associated with the topology.
Design of High-Frequency FM Transceiver
Voltage
Adder
Input
Signal

DC
Bias
Mixer
PA
VCO
• FM Transmitter
Antenna
The information signal is first added to a DC signal which
enables the VCO (voltage controlled oscillator) to have the maximal
operation linearity. The VCO acts as the FM modulator. The
modulated signal is up-converted by the mixer to wanted carrier
frequency. The PA (power amplifier) further increases the signal level
which is transmitted by the antenna.
Matching
Network
RC
Network
FM Modulator
Local
Oscillator
• FM Receiver
Antenna
The modulated signal sent out by the transmitter
is received by the antenna at the receiver end and is
amplified by the LNA (low noise amplifier). The mixer
down-converts this signal to intermediate frequency
(IF), realizing the tuning function. The PLL (phase
lock loop) demodulates the FM signal and thus the
original information is recovered for processing.
Mixer
Matching
Network
LNA
IFA
Crystal
Filter
Local
Oscillator
Design Note
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DC Bias: Voltage regulator that has very low output resistance.
VCO: Current Starved Ring Oscillator.
Power Amplifier: Class A cascade common-emitter amplifier with emitter degeneration and resonant load.
Antenna: Loop antenna with 50Ω radiant impedance.
LNA: Cascode amplifier with input matching and output buffer.
Mixer: Gilbert cell.
Local Oscillator: Colpitts oscillator.
PLL: Phase frequency detector, charge pump, loop filter, and VCO.
PLL
FM
Demodulator
PA
Output
Signal
Receiver Chip Layout