Post on 08-Aug-2018
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Super-Regenerative Receiver
Ultra low-power RF Transceiver forhigh input power & low-data rateapplications
ECEN 665 TAMU AMSC
Thanks to this material to Felix Fernandez
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Overview
{ Invented by Armstrong in 1922 and widely used in
vacuum tube circuits until the 1950s{ It was replaced by the super-heterodyne receiver due
to its poor selectivity and sensitivity
{ Pros:z Small number of components allow for high integration
z Low power
z High energy efficiency
{ Consz poor sensitivity
z poor selectivity
z low data-rate
z limited demodulation capability
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Super-regenerative Receiver
Block Diagram
Selective
Network
Ka(t)
Quench
Oscillator
LNAEnvelope
DetectorLPF
Demodulator
Super-regenrativeOscillator
0
QU
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Super-regenerative Receiver
Block Diagram & Basic Model
( )tALV
dtdVG
dtVdC cos2
2
=++ ( ) ( ) ( )
( ) ( )tG
Ate
G
A
GtAe
GjAe
GjAV
dC
Gt
d
tj
d
tj
d
dd
020
000
sinsin
sin22
+=
+=
+
220
2
21
2
=
=
=
CG
LC
C
G
d
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WWII German Air Interception(first generation SRR, circa 1940)
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Operation Fundamentals
Ga(t) = G0
Ga(t) = 0 [Ga(t) is a negative conductance]
Ga(t) >> G0
Pole-Zero Map
Real Axis
ImaginaryAxis
-8000 -6000 -4000 -2000 0 2000 4000-8
-6
-4
-2
0
2
4
6
8x 10
4
Bode Diagram
Frequency (rad/sec)10
410
510
6-40
-20
0
20
40
60
80
100
120
140From: Input Point To: Output Point
Magnitude(dB)
stable
operation
close
to
unstab
le
(high
Q)
unstable
operat
ion
( )v(t)i(t)tG =
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Operation Modes
z Linear: The self
sustained oscillationsare quenched beforethey reach theirmaximum amplitude.The height of the SRO
output has a linearrelationship with the RFinput power.
z Logarithmic: The self
sustained oscillationsare allowed to reachtheir maximumamplitude. The areaenclosed by the
envelope of the SROoutput has a logarithmicrelationship with the RFinput power
vsro
(t)
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Quenching Mode
{ External Quenching:
z The oscillations of theSRO are quenched byan external oscillatorthat controls the
negative admittanceat a fixed frequency
{ Self Quenching
z The oscillation of theSRO are controlled bya feedback networkwhich quenches the
oscillation after theyhave reached acertain threshold
Low RF Input High RF Input Low RF Input High RF Input
0 1 0 1
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Building Blocks Operation
{ LNA
z Feeds the RF input to the SROz Provides antenna matchingz Isolates SRO oscillations from the antenna
{ SROz Generate the oscillations needed for the super-
regenerative operation{ Quench Oscillator
z Quench the SRO oscillations according to thequenching mode
{ Demodulatorz Detect the SRO oscillation envelope and digitize the
signal
{ Tuning (PLL)z Provide tuning ability to the selective network
(original tuning scheme was manual tuning)
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Super Regenerative System
Design Equations
( )
( )
( )
( )( )
=
=
=
t
t
bt
bt
dtt
dtt
dtt
s
ets
etp
eK
0
0
0
0
0
Super regenerative gain
Output pulse shape
Sensitivity function
Frequency response is given by the Fourier transform of theRF envelope and the sensitivity function.
ttQ
O
e)(2
(t)
AVG
ta tbt
ta tbt
s(t)1
p(t)
i(t)
G0 -Ga(t) L Ci(t)
{ })()( tstiF
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Selective Network Design Equations
( )2
000
2
000
2
2
++=
ss
sKsG
( ) ( )( ) aKsGsGsH
+= 1
: depends on the
quench control signal
( ) ( )( )tKKt a00 1=
( ) )(21
ttQ =
K0: maximum amplificationKa(t): variable gain controlled by quench signal
0: quiescent damping factorAVG: damping factor average value ( ) attaa tKK ==
*
( ) ( ) 20*
000
2
000
12
2
++= sKKs
s
KsHa
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Quench signal frequency limitations
{ Avoid resonance fromprevious cycles(a.k.a. hangover)
{ The hangovercoefficient is therelationship betweenthe amplitudes of the
first cycle and thesecond (unwanted)one.
QUAVGeh
02
=
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Examples
{ Setup
z FRF= 10kHz
z FINT=10.5kHz
z FQUENCH=100Hzz Q = 5
z LPF: 3RD order Butterworth with f3dB 800Hz
z Several quench signals
{ System was simulated using MatLabsSimulink.
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Sine Quench
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Sawtooth Quench
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-0.05 -0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04 0.05-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5Frequency Response for Different Damping Functions
Nomralizad Frequency
NormalizedMagnitude
SAWTOOTHSINE
SAWTOOTH 2
Different Damping Functions (t)
As the transition slopeis reduced the SRRshows an narrowerfrequency response oran increase selectivity
SRR selectivity iscontrolled mainly bythe slope at thetransition point
Better selectivityimplies betterperformance under thepresence of interferers
mSAW > mSAW2
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Which is the optimal (better selectivity)damping function for a give application?
Quench gain or oscillations death rate
Sampling (frequency selectivity)
SR gain or oscillations growth rate
Find the Optimum for a Given Application !
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Optimal damping for this case
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Modern Applications
{ SRR today:
z Ultra low power communication require minimumenergy consumption during the RF communication
{ Application fields:
z
short-distance data-exchange wireless link withmedium data-rate, such as sensor network, homeautomation, robotics, computer peripherals, orbiomedicine.
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Case Studies [6]
A low-power 1-GHz super-regenerative transceiver with time-shared PLL control
The SRR behaves like a PLL for a short amount of time to:
Tune the frequency
Find the optimal transition point
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Case Studies [6]
Operating Voltage: 2.4v
Current of RX mode: 1.5mA
Sensitivity: -105dBm
Selectivity (-5dB attenuation): 150kHz
Data-Rate: 150kbits/s
Frequency Range: 300-1500MHz
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Case Studies [5]
A 400uW-RX, 1.6mW-TX Super-Regenerative Transceiver for Wireless Sensor
Networks
The SRO is based on a extremely high-Q BAW resonator thus reducing the requiredresolution on the Q controlling scheme.
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Case Studies [5]
Operating Voltage: 1v
Current of RX mode: 400uA
Sensitivity: -100.5dBm
Bandwidth: 500kHz
Data-Rate: 5kbits/s
Frequency: 1.7GHz
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Case Studies [4]
A 3.6mW 2.4-GHz Multi-Channel Super-Regenerative Receiver in 130nm CMOS
Similar to case study [1] but the quench/damp signal generated is shaped by the digital
controller to improved the selectivity.critical point
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Case Studies [4]
Operating Voltage: 1.2v
Current of RX mode: 3mA
Sensitivity: -80dBm
Selectivity (channel space): 10MHz
Data-Rate: 500kbits/s
Frequency Range: 2.4GHz ISM
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Challenges:
{ Selectivity:z Maximize control of quench shape and frequency
{ Sensitivity:z 5-20dB lower than heterodyne ones
{ LC tank tuning:z Low-power tuning
{ Data rate:z How to decrease the quench to modulation frequency
ratio
{ Integration level:z On-chip LC tank with enhanced Q (SAW, BAW)
{ Spread spectrum:z PN synchronization and frequency de-hopping
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References:
[1] E. H. Armstrong, Some recent developments of regenerative circuits, Proc. IRE, vol. 10, pp. 244-260, Aug.
1922
[2] J. R. Whitehead, Super-Regenerative Receivers. Cambridge Univ. Press, 1950.
[3] F.X. Moncunill-Geniz, P. Pala-Schonwalder, O. Mas-Casals, A generic approach to the theory of
superregenerative reception,IEEE Transactions on Circuits and Systems-I, vol. 52, No.1, pp:54 70, Jan.
2005.
[4] J.Y. Chen, M. P. Flynn, and J. P. Hayes, A 3.6mW 2.4-GHz multi-channel super-regenerative receiver in 130nm
CMOS,In Proc. IEEE Custom Integrated Circ. Conference, pp. 361-364, Sep. 2005.
[5] B. Otis, Y. H. Chee, and Y. Rabaey, A 400uW-RX, 1.6mW-TX super-regenerative transceiver for wireless
sensor networks,Digest of Technical Papers of the IEEE Int. Solid-State Circ. Conference, vol. 1, pp. 396-397and p. 606, San Francisco, Feb. 2005.
[6] N. Joehl, C. Dehollain, P. Favre, P. Deval, M. Declerq, A low-power 1-GHz super-regenerative transceiver with
time-shared PLL control,IEEE J. of Solid-State Circuits, vol. 36, pp:1025 1031, Jul. 2001.
[7] P. Favre, N. Joehl, A. Vouilloz, P. Deval, C. Dehollain, M.J. Declercq, A 2-V 600-A 1-GHz BiCMOS super-
regenerative receiver for ISM applications,IEEE J. of Solid-State Circuits, vol. 33, pp:2186 2196, Dec. 1998.
[8] F.X. Moncunill-Geniz, P. Pala-Schonwalder, C. Dehollain, N. Joehl, M. Declercq, A 2.4-GHz DSSS
superregenerative receiver with a simple delay-locked loop,IEEE Microwave and Wireless ComponentsLetters, vol 15, pp:499 501, Aug. 2005.
[9] A. Vouilloz, M. Declercq, C. Dehollain, A low-power CMOS super-regenerative receiver at 1 GHz,IEEE
J.Solid-state circuits, vol. 36, pp:440 451, Mar. 2001.
[10] A. Vouilloz, M. Declercq, C. Dehollain, Selectivity and sensitivity performances of superregenerative
receivers, Proc. ISCAS98, vol.4, pp:325-328, Jun. 1998.
[11] F.X. Moncunill-Geniz, C. Dehollain, N. Joehl, M. Declercq, P. Pala-Schonwalder, A 2.4-GHz Low-Power
Superregenerative RF Front-End for High Data Rate Applications,Microwave Conference, 2006. 36thEuropean, pp:1537 1540, Sept. 2006