MAI MULTE A TINTA UNI ON TO A ONI O NI NINI
US010033420B2
( 12 ) United States Patent
Lien et al
.
( 45 ) Date of Patent :
( 10 ) Patent No
. : US 10 , 033 , 420 B2
Jul . 24 , 2018
( 54 ) WIRELESS COMMUNICATION RECEIVER
( 56 )
References Cited
( 71 ) Applicant
: MEDIATEK Inc . , Hsin - Chu ( TW )
U . S . PATENT DOCUMENTS
7 , 385 , 443 B1 * 6 / 2008 Denison . . .
HO3F 3 / 38330 / 10
( 72 ) Inventors : Yuan - Ching Lien , Taipei ( TW ) ; Eric
Klumperink , Enschede ( NL ) ; Bram
Nauta , Enschede ( NL )
9 , 071 , 219 B2 9 , 263 , 995 B2 6 / 2015 De Geronimo et al . 2 / 2016 Wang et al .( Continued )
( 73 ) Assignee : MEDIATEK INC . , Hsin - Chu ( TW )
FOREIGN PATENT DOCUMENTS
( * ) Notice :
Subject to any disclaimer , the term of this
patent is extended or adjusted under 35
U . S . C . 154 ( b ) by 0 days .
WO 2011044585 A1 4 / 2011
OTHER PUBLICATIONS
( 21 ) Appl . No . : 15 / 469 , 690
( 22 ) Filed :
Mar
. 27 , 2017
( 65 )
Prior Publication Data
US 2017 / 0373710 A1 Dec . 28 , 2017
Related U . S . Application Data
( 60 ) Provisional application No . 62 / 353 , 587 , filed on Jun .
23 , 2016 .
( 51 ) Int . CI .H04B 1 / 26
( 2006 . 01 ) H04B 1 / 28 ( 2006 . 01 ) H04B 1 / 10 ( 2006 . 01 ) H04B 1 / 16 ( 2006 . 01 ) HO3H 11 / 12( 2006 . 01 )
( 52 ) U . S . CI . CPC . . . H04B 1 / 16 ( 2013 . 01 ) ; H03H 11 / 1204( 2013 . 01 ) ; H04B 1 / 1018 ( 2013 . 01 )
( 58 ) Field of Classification Search
CPC . . . HO3H 11 / 0433 ; HO3H 11 / 0455 ; HO3H
11 / 0466 ; HO3H 11 / 0477 ; H04B 1 / 16
. . . 455 / 307 , 333
See application file for complete search history .
Andrews , et al . : " A Passive - Mixer - First Receiver with Baseband
Controlled RF Impedance Matching , < 6dB NF , and > 27dBm Wideband IIP3 ” ; ISSCC 2010 / Session 2 / mm - Wave Beamforming
& RF Building Blocks / 2 . 5 ; pp . 46 - 48 .
( Continued )
Primary Examiner — Simon Nguyen
( 74 ) Attorney , Agent , or Firm - McClure , Qualey &
Rodack , LLP( 57 )
ABSTRACT
Provided is a wireless communication receiver including an
antenna for receiving an RF signal ; a first mixer , coupled to
the antenna , for performing frequency conversion on the RF
signal from the antenna by mixing the RF signal with a local
oscillator signal to provide a first intermediate frequency
( IF ) signal ; and a first filter , coupled to the first mixer
,
configured to pass a predetermined band of frequencies of
the first IF signal and to generate a first channel signal . The
first filter includes a negative feedback loop coupled to the
first mixer for performing negative feedback loop control on
the first IF signal ; and a positive capacitive feedback loop
coupled to the first mixer for performing positive capacitive
feedback loop control on the first IF signal , the negative
feedback loop and the positive capacitive feedback loop
being coupled in parallel .
5 Claims
, 5 Drawing Sheets
USPC . . .
. . .
positive
feedback BlockerAKAT
in - bandHof
floRF1
negative
feedback
in - band Blocker Dgolding
0US 10 , 033 , 420 B2
Page 2
( 56 )
References Cited
U . S . PATENT DOCUMENTS . . .2007 / 0237273 A1 * 10 / 2007 Tan . . . HO3H 11 / 1291
375 / 3502012 / 0196555 A1 * 8 / 2012 Igarashi . . . H04B 1 / 30
455 / 3412013 / 0095779 A1 * 4 / 2013 Katsube . . . HO3H 11 / 1252
455 / 232 . 1 2015 / 0137882 A1 * 5 / 2015 Ciubotaru . . . HO3H 11 / 0405 327 / 558 2015 / 0180523 A1 * 6 / 2015 Tasic . . . H04B 1 / 26 375 / 3162017 / 0040972 A1 * 2 / 2017 Taya
. . HO3H 11 / 1252OTHER PUBLICATIONS
Chen , et al . : “ Reconfigurable Receiver With Radio Frequency Cur
rent - Mode Complex Signal Processing Supporting Carrier Aggre
gation " ; IEEE Journal of Solid - State Circuits , vol . 50 , No . 12 , Dec .
2015 , pp . 3032 - 3046 .
Andrews , et al . : " Implications of Passive Mixer Transparency for Impedance Matching and Noise Figure in Passive Mixer - First
Receivers ” ; IEEE Transactions on Circuits and Systems — I : Regu
lar Papers , vol . 57 , No . 12 , Dec . 2010 ; pp . 3092 - 3103 .
Soer , et al . : : A 0 . 2 - to - 2 . 0GHz 65nm CMOS Receiver Without LNA Achieving > 11dBm IIP3 and < 6 . 5 dB NF ; ISSCC 2009 / Session
12 / RF Building Blocks / 12 . 4 ; pp . 221 - 224 .
Darvishi , et al . : " A 0 . 3 - to - 1 . 2GHz Tunable 4th - Order Switched gm - C Bandpass Filter with > 55dB Ultimate Rejection and Out - of
Band IIP3 of + 29dBm ” ; ISSCC 2012 / Session 21 / Analog
Techniques / 21 . 1 ; pp . 358 - 360 .
TIPO Office Action dated Jan . 12 , 2018 in Taiwan application ( No .
106115939 ) .
U . S . Patent
Jul
. 24 , 2018
Sheet 1 of 5
US 10 , 033 , 420 B2
100
-
109
fogo
0090
- - - - 105A
2L0 + oy Logo
2L0 - 0 -
00180
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mixer
9M1
filter C11
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0270
QM7
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momento
omeone
tot
.OPZO
IRFANO
Ic14m
090
SM8
VVmixer
105B
FIG . 1
U . S . Patent
Jul . 24 , 2018
Sheet 2 of 5
US 10 . 033 , 420 B2
POSE
feedback
Blocker
?
in
- band
* fRE
negative
feedback
in
- hard
4G
AC1
Blocker
f105
" topi
OP
FE
. 2
U . S . Patent
Jul . 24 , 2018
Sheet 3 of 5
US 10 , 033 , 420 B2
100
= = = ... ... ... * * .-
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U . S . Patent
Jul
. 24 , 2018
Sheet 4 of 5
US 10 , 033 , 420 B2
400
- 405
mixer
- 407
OM1
filter C11
0180
OM2
0180
OM3
1h000
op
Bagh
00
balun
A1
FIG . 4
U . S . Patent
Jul
. 24 , 2018
Sheet 5 of 5
US 10 , 033 , 420 B2
500
505A2
mixer00
9M9
0180
M10
0180
9M11
- 507A
filter C1
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FIG . 5
US 10 , 033 , 420 B2
WIRELESS COMMUNICATION RECEIVER
FIG . 4 shows a circuit diagram for a single - channel
wireless communication receiver according to an embodi
This application claims the benefit of U . S . Provisional
ment of the application .
Patent application Ser . No . 62 / 353 , 587 , filed Jun . 23 , 2016 ,
FIG . 5 shows a circuit diagram for a two - channel - four
the disclosure of which is incorporated by reference herein 5 mixer wireless communication receiver according to an
in its entirety .
embodiment of the application .
In the following detailed description , for purposes of
TECHNICAL FIELD
explanation , numerous specific details are set forth in orderto provide a thorough understanding of the disclosed
The disclosure relates in general to a wireless communi - 10 embodiments . It will be apparent , however , that one or more
cation receiver .
embodiments may be practiced without these specificdetails . In other instances , well - known structures and
BACKGROUND
devices are schematically shown in order to simplify the
drawing .
Many modern radio frequency ( RF ) receivers use a direct 15
DETAILED DESCRIPTION
conversion or zero - IF ( ZIF ) architecture . RF signals
received at an antenna are fed through mixer driven by a
Disclosed are wireless communication receiver struclocal oscillator ( LO ) and subsequently filtered to produce a
tures . Note , embodiments described herein include variousbaseband channel demodulated output signal . Ideally , RF 20 elements and limitations , with no one element or limitation
power amplifiers of the RF receiver would act linearly ,
contemplated as being a critical element or limitation . Eachfaithfully reproducing an amplified RF signal at their output
of the claims individually recites an aspect of the invention
with no distortion . in its entirety . One or multiple systems , devices , compo
As for the design targets for the RF receiver , low noise nents , etc . may comprise one or more embodiments , which
figure ( NF ) , high third - order intercept point ( IIP3 ) and high 25 may include some elements or limitations of a claim being
central frequency ( fc ) are required . performed by the same or different systems , devices , com
The mixer - first receiver has advantages , for example ,
ponents , etc . The embodiments described hereinafter
good linearity , high tunable Q and low NF . The requirement embody various aspects and configurations within the scope
on improving the IIP3 of the receiver is one of the issues .
and spirit of the invention , with the figures illustrating
Further , to reject out - band signals , higher order BPF 30 exemplary and non - limiting configurations .
( band pass filter ) may be used . But
, numerous off - chip BPF
Technical terms of the disclosure are based on general
would increase the device cost .
definition in the technical field of the disclosure . If the
Thus , there needs a wireless communication receiver
disclosure describes or explains one or some terms , definiarchitecture which achieves high linearity and requires
tion of the terms is based on the description or explanation
simple external low cost LPF ( low pass filter ) or BPF .
35 of the disclosure . Each of the disclosed embodiments hasone or more technical features . In possible implementation ,
SUMMARY
one skilled person in the art would selectively implementpart or all technical features of any embodiment of the
According to one embodiment , provided is a wireless
disclosure or selectively combine part or all technical feacommunication receiver including an antenna for receiving 40 tures of the embodiments of the disclosure .
FIG . 1 shows a circuit diagram for a wireless communi
a wireless communication signal ; a first mixer , coupled to
cation receiver according to an embodiment of the applicathe antenna , for performing frequency conversion on the
tion . The wireless communication receiver 100 includes anreceived wireless communication signal from the antenna by
antenna 101 , a plurality of mixers ( two mixers 105A andmixing the wireless communication signal with a local 45 105B in this embodiment but the application is not limited
oscillator signal to provide a first intermediate frequency by ) and a plurality of filters ( two filters 107A and 107B in( IF ) signal ; and a first filter , coupled to the first mixer , this embodiment , but the application is not limited by ) . The
configured to pass a predetermined band of frequencies of wireless communication receiver may further optionally
the first IF signal of the first mixer and to generate a first include a balun ( balanced to unbalanced ) circuit 103 and two
channel signal . The first filter includes : a negative feedback 50 input capacitors Cin1 and Cin2 . In other possible embodi
loop coupled to the first mixer for performing negative
ments of the application , the input capacitors Cinl and Cin2
feedback loop control on the first IF signal from the first may be omitted .
mixer ; and a positive capacitive feedback loop coupled to
The antenna 101 is for receiving an RF signal . In FIG . 1 ,
the first mixer for performing positive capacitive feedback the equivalent circuit model of the antenna 101 is also loop control on the first IF signal from the first mixer , the 55 shown , which includes a serially - connected resistor element
negative feedback loop and the positive capacitive feedback
Rs and a voltage source Vs .
loop being coupled in parallel .
The balun circuit 103 is coupled to the antenna 101 . Thebalun circuit 103 is an electrical device that converts
BRIEF DESCRIPTION OF THE DRAWINGS
between a balanced signal and an unbalanced signal . The60 details of the balun circuit 103 are not specified here for
FIG . 1 shows a circuit diagram for a wireless communi -
simplicity .
cation receiver according to an embodiment of the applica The mixers 105A and 105B are coupled to the balun
tion . circuit 103 . The mixers 105A and 105B perform frequency
FIG . 2 shows an equivalent circuit model of the receiver
conversion on the received RF signals from the antenna 101
of FIG . 1 according to the embodiment of the application . 65 and output the resulting frequency - converted signal to the
FIG . 3 shows the transfer functions of the receiver of the subsequent filters 107A and 107B , respectively . Further , the
embodiment of the application .
mixers 105A and 105B mix the received RF signal with aUS 10 , 033 , 420 B2
C
local oscillator signal to provide an intermediate frequency
tors C5 - C8 , C13 - C16 and Ca2 . The filter 107A will be
( IF ) signal to the subsequent filters 107A and 107B , respec - explained . The details of the filter 107B may be referenced
tively . In the embodiment of the application , the mixers
to that of the filter 107A and thus are omitted here .
105A and 105B may have the same or similar circuit
In the filter 107A , the capacitor C1 and the resistor
structures and operations . 5 element RF1 are coupled in parallel between the nonThe filters 107A and 107B are coupled to the mixers 105A
inverting input terminal and the inverting output terminal of
and 105B . The filters 107A and 107B operate to suppress an the operational amplifier OP1 . The capacitor C2 and the interfering wave from a neighbored channel . The filters resistor element RF2 are coupled in parallel between the
107A and 107B are configured to pass a predetermined band
inverting input terminal and the non - inverting output termi
of frequencies from the output signals of the mixers 105A 10 nal of the operational amplifier OP1 . The capacitor C3 isand 105B and generate the output I / Q channel signals . coupled between the non - inverting input terminal of the
In the embodiment of the application , the filters 107A and operational amplifier OP1 and one terminal of the capacitor
107B may have the same or similar circuit structures and
Cal . The capacitor C4 is coupled between the inverting
operations .
input terminal of the operational amplifier OP1 and another
The mixers 105A and 105B will now be explained . The 15 terminal of the capacitor Cal . The capacitor C9 is coupled
mixer 105A includes NMOS transistors M1 - M4 , as shown from the non - inverting input terminal of the operational in FIG . 1 . The NMOS transistor M1 includes a source ( or amplifier OP1 to GND . The capacitor C10 is coupled from
drain ) coupled to the non - inverted input of the operational
the inverting input terminal of the operational amplifier OP1
amplifier OP1 of the filter 107A , a drain ( or source ) coupled to GND . The capacitor C11 is coupled from the output
to the input capacitor Cinl and a gate receiving the clock 20 terminal of the operational amplifier OP1 to GND . The
signal 00 . The NMOS transistor M2 includes a source ( or capacitor C12 is coupled from the output terminal of the
drain ) coupled to the source ( or drain ) of the NMOS operational amplifier OP1 to GND . The capacitors C9 - C12
transistor M1 and to the non - inverted input of the opera
may be parasitic capacitors or real capacitors . The resistor
tional amplifier OP1 of the filter 107A , a drain ( or source ) elements R1 - R3 are coupled in series between the non
coupled to the input capacitor Cin2 and a gate receiving the 25 inverting output terminal and the inverting output terminal
clock signal 0180 . The NMOS transistor M3 includes a
of the operational amplifier OP1
. The capacitor Cal ( also
source ( or drain ) coupled to the inverted input of the referred as “ the attenuation capacitor " ) is further coupled in
operational amplifier OP1 of the filter 107A , a drain ( or
parallel with the resistor element R2 . The resistor elements
source ) coupled to the input capacitor Cinl and a gate R1 - R3 and the capacitor Cal form an attenuator A1 .receiving the clock signal 0180 . The NMOS transistor M4 30 In the filter 107B , the capacitor C5 and the resistor
includes a source ( or drain ) coupled to the source ( or drain ) element RF3 are coupled in parallel between the non
of the NMOS transistor M3 and to the inverted input of the inverting input terminal and the inverting output terminal of
operational amplifier OP1 of the filter 107A , a drain ( or
the operational amplifier OP2 . The capacitor C6 and the
source ) coupled to the input capacitor Cin2 and a gate
resistor element RF4 are coupled in parallel between the
receiving the clock signal 00 .
35 inverting input terminal and the non - inverting output termiThe mixer 105B includes NMOS transistors M5
- M8
, asnal of the operational amplifier OP2 . The capacitor C7 is
shown in FIG . 1 . The NMOS transistor M5 includes a source coupled between the non - inverting input terminal of the ( or drain ) coupled to the non - inverted input of the opera operational amplifier OP2 and one terminal of the capacitor
tional amplifier OP2 of the filter 107A , a drain ( or source )
Ca2 . The capacitor C8 is coupled between the inverting
coupled to the input capacitor Cinl and a gate receiving the 40 input terminal of the operational amplifier OP2 and another
clock signal 090 . The NMOS transistor M6 includes a terminal of the capacitor Ca2 . The capacitor C13 is coupled
source ( or drain ) coupled to the source ( or drain ) of the from the non - inverting input terminal of the operational
NMOS transistor M5 and to the non - inverted input of the
amplifier OP2 to GND . The capacitor C14 is coupled from
operational amplifier OP2 of the filter 107A , a drain coupled
the inverting input terminal of the operational amplifier OP2
to the input capacitor Cin2 and a gate receiving the clock 45 to GND . The capacitor C15 is coupled from the output signal 0270 . The NMOS transistor M7 includes a source ( or terminal of the operational amplifier OP2 to GND . Thedrain ) coupled to the inverted input of the operational capacitor C16 is coupled from the output terminal of the
amplifier OP2 of the filter 107A , a drain ( or source ) coupled
operational amplifier OP2 to GND . The capacitors C13 - C16
to the input capacitor Cinl and a gate receiving the clock may be parasitic capacitors or real capacitors . The resistor signal 0270 . The NMOS transistor M8 includes a source ( or 50 elements R4 - R6 are coupled in series between the non drain ) coupled to the source ( or drain ) of the NMOS inverting output terminal and the inverting output terminal transistor M7 and to the inverted input of the operational of the operational amplifier OP2 . The capacitor Ca2 ( also
amplifier OP2 of the filter 107A , a drain ( or source ) coupled
referred as “ the attenuation capacitor ” ) is further coupled in
to the input capacitor Cin2 and a gate receiving the clock
parallel with the resistor element R5
. The resistor elements
signal 090 .
55 R4 - R6 and the capacitor Ca2 form an attenuator A2 .The clock signals 00 , 090 , 0180 and $ 270 are four
The output of the operational amplifier OP1 is I - channel
clock phases generated by a clock divider 109 by dividing output and the output of the operational amplifier OP2 is
the oscillator signals 2LO + and 2LO - wherein the oscillator
Q - channel output . Thus , the receiver 100 of FIG . 1 is a
signals 2LO + and 2LO - are generated by a local oscillator two - channel receiver . Further , the circuit configuration of
( not shown ) .
60 the operational amplifiers OP1 and OP2 are not specified
The filter 107A is coupled to the mixer 105A and the filter
hereby .
107B is coupled to the mixer 105B . The filter 107A is an The passband width of the filters 107A and 107B may be
active filter which includes the operational amplifier OP1
,
changed by controlling the capacitance value of the capaci
the resistor elements RF1 - RF2 and R1 - R3 , and the capaci t ors C1 - C8 or the resistance of the resistor elements R1 - R6 .tors C1 - C4 , C9 - C12 and Cal . The filter 107B is also an 65
In other possible embodiment of the application , the
active filter which includes the operational amplifier OP2 , capacitors C1 , C2 , C5 and / or C6 may be coupled to GND .the resistor elements RF3 - RF4 and R4 - R6 , and the capaci -
That is , the capacitors C1 , C2
, C5 and / or C6 may be coupled
US 10 , 033 , 420 B2
between the respective sources ( or drains ) of the transistors embodiment of the application . The wireless communication M1 - M8 and GND , which is still within the spirit and scope receiver 500 includes an antenna 501 , a balun circuit 503 ,
of the application . For example , the capacitor C1 may be
two input capacitors Cin1 - Cin2 , four mixers 505A1 , 505A2 ,
coupled between the source ( or drain ) of the transistor M1
505B1 and 505B2 and two filters 507A and 507B . The
and GND , and so on . 5 mixers 505A1 , 505B1 and the filters 507A , 507B may haveFIG . 2 shows an equivalent circuit model of the receiver
the same or similar circuit structure and operations with the
of FIG . 1 according to the embodiment of the application . In mixers 105A , 105B and the filters 107A , 107B of FIG . 1 of
FIG . 2 , the single - ended diagram is shown for simplicity ,
the embedment of the application . Details of the mixerssome elements ( for example , the balun circuit 103 , the filter 505A1 , 505B1 and the filters 507A , 507B are omitted here .
107B , the operational amplifier OP2 , the resistor element 10
Now , the mixers 505A2 and 505B2 will be explained . The
RF2
, the capacitors C2 and C4 of the filter 107A ) are
mixer 505A2 includes NMOS transistors M9
- M12 . The
omitted .
As shown in FIG . 2 , the capacitor C1 ( and also the
NMOS transistor M9 includes a source ( or drain ) coupled to
capacitor C2 ) and the operational amplifier OP2 form a
the capacitor C3 of the filter 507A , a drain ( or source )
negative feedback loop for performing negative feedback 15 coupled to the input capacitor Cinl and a gate receiving the
loop control on the output signals from the mixer 105A . The
clock signal 00 . The NMOS transistor M10 includes a
capacitor C3 ( and also the capacitor C4 ) and the attenuator
source ( or drain ) coupled to the source ( or drain ) of the
A1 form a positive capacitive feedback loop for performing
NMOS transistor M9 and to the capacitor C3 of the filter
positive capacitive feedback loop control on the output 507A , a drain ( or source ) coupled to the input capacitor Cin2
signals from the mixer 105A . The negative feedback loop 20 and a gate receiving the clock signal Ø180 . The NMOS
and the positive capacitive feedback loop are coupled in
transistor M11 includes a source ( or drain ) coupled to the
parallel . capacitor C4 of the filter 507A , a drain ( or source ) coupled
The gain ( A0 ) of the operational amplifier OP1 is higher
to the input capacitor Cinl and a gate receiving the clock
than 1 and the gain ( A1 ) of the attenuator A1 is lower than signal 0180 . The NMOS transistor M12 includes a source
1 . If the gain ( AO ) of the operational amplifier OP1 and the 25 ( or drain ) coupled to the source ( or drain ) of the NMOS
gain ( A1
) of the attenuator Al are tuned to be large , then the
transistor M11 and to the capacitor C4 of the filter 507A , a
Q factor of the receiver is also large . In other words , if
drain coupled to the input capacitor Cin2 and a gate receiv
A0 * A1 is larger , then Q is also larger .
ing the clock signal 00 .
At the antenna input side of FIG . 2 , the in - band signal , i . e .
Similarly , the mixer 505B2 includes NMOS transistors
the wanted signal , is small while the " blocker ” , i . e . the 30 M13 - M16 . The NMOS transistor M13 includes a source ( or
out - band signal which is unwanted signals , is large . After
drain ) coupled to the capacitor C7 of the filter 507B , a drain
processed by the receiver of the embodiment of the appli
( or source ) coupled to the input capacitor Cinl and a gate
cation , the in - band signal is amplified while the out - band
receiving the clock signal 090 . The NMOS transistor M14
signal is attenuated .
includes a source ( or drain ) coupled to the source ( or drain )
As shown in output side of the operational amplifier 35 of the NMOS transistor M13 and to the capacitor C7 of the OP1 / OP2 , the receiver according to the embodiment of the filter 507B , a drain ( or source ) coupled to the input capacitor
application has better out - band rejection because of the high
Cin2 and a gate receiving the clock signal 0270 . The NMOS
order LPF / BPF .
transistor M15 includes a source ( or drain ) coupled to the
FIG . 3 shows the transfer functions of the receiver 100 of
capacitor C8 of the filter 507B , a drain coupled to the input
the embodiment of the application . As shown in FIG . 3 , at 40 capacitor Cinl and a gate receiving the clock signal 0270 .
the input side of the mixer 105 , the transfer function TF1 has The NMOS transistor M16 includes a source ( or drain )
the theoretical 4th order BPF ( band pass filter ) characteristic coupled to the source ( or drain ) of the NMOS transistor M15 wherein “ fLO ” refers to the LO frequency ( i . e . the RF and to the capacitor C8 of the filter 507B , a drain ( or source ) frequency ) and “ BW ” is the bandpass filter bandwidth . At coupled to the input capacitor Cin2 and a gate receiving the
the input side of the operational amplifier OP2 , the transfer 45 clock signal 090 .
function TF2 has the theoretical 2nd order LPF characteristic .
As shown in FIG . 5 , the I - channel has the mixers 505A1
In the transfer function TF2 , " f3dB , BB ” is the baseband and 505A2 and the Q - channel has the mixers 505B1 and
signal bandwidth , " rO ” is the output impedance of the
505B2 . The mixers 505A1 and 505A2 , coupled in parallel ,
operational amplifier OP2 and “ CO ” is the capacitance at the are configured to perform frequency conversion on the output side of the operational amplifier OP2 . At the output 50 received RF signal from the antenna 101 by mixing the RF side of the operational amplifier OP2 , the transfer function signal with the local oscillator signal ( i . e . the clock signal )
TF3 has the theoretical 2nd order LPF characteristic . to provide the output signal to the filter 507A . The mixers
FIG . 4 shows a circuit diagram for a single - channel
505A1 and 505A2 substantially have the same or similar
wireless communication receiver 400 according to an
functions and circuit configuration . Similarly , the mixers
embodiment of the application . The wireless communication 55 505B1 and 505B2 , coupled in parallel , are configured to
receiver 400 includes an antenna 401 , a balun circuit 403 ,
perform frequency conversion on the received RF signal
two input capacitors Cin1 - Cin2 , a mixer 405 and a filter 407 . from the antenna 101 by mixing the RF signal with the local
The mixer 405 and the filter 407 may have the same or oscillator signal ( i . e . the clock signal ) to provide the output
similar circuit structure and operations with the mixer 105A ) signal to the filter 507B . The mixers 505B1 and 505B2
105B and the filter 107A / 107B of FIG . 1 of the embedment 60 substantially have the same or similar functions and circuit
of the application . Thus , the circuit operations of the single
configuration .
channel receiver 400 may be referenced to that of the Also , the two - channel - four - mixer receiver 500 of the
two - channel receiver 100 . Also , the single - channel receiver
embodiment of the application has improved LPF and BPF
400 of the embodiment of the application has improved LPF performance .
and BPF performance .
65
In possible embodiment of the application , the resulting
FIG . 5 shows a circuit diagram for a two - channel - four - signals from the operational amplifiers OP1 and OP2 may bemixer wireless communication receiver 500 according to an
further converted by analog - to - digital converters ( ADC )
US 10 , 033 , 420 B2
( not shown ) into digital signals , which are then subject to
wherein the negative feedback loop includes an opera
digital processing operations by a digital baseband unit ( not
tional amplifier , a first capacitor and a second capacitor ,
shown ) .
the first capacitor being coupled between a first input
In the above embodiments of the application , the clock terminal and a first output terminal of the operational
signal fed into the mixers 105A , 105B , 405 , 505A1 , 505A2 , 5
amplifier , and the second capacitor being coupled
505B1 and 5056B2 has four clock phases $ 0 , 090 , Ø180
between a second input terminal and a second output
and $ 270 . However , the application is not limited by . In terminal of the operational amplifier ;
other possible embodiments of the application , the clock
wherein the positive capacitive feedback loop includes : a
signal fed into the mixer ( s ) of the receiver may have six or
third capacitor and a fourth capacitor ; and an attenua
eight or more clock phases , which is still within the spirit of 10
the application .
tor , coupled to the third capacitor and the fourth capaci
As described above , compared with the state of the art tor ,
( having 1st order LPF and / or 2nd order BPF ) , the receiver
the third capacitor is coupled between the first input
according to the embodiments of the application include terminal of the operational amplifier and a terminal of
higher - order filter ( for example , but not limited by , theoreti - 15 an attenuation capacitor of the attenuator , and
cal 2nd order LPF and / or theoretical 4th order BPF ) . Thus , the
the fourth capacitor is coupled between the second inputreceiver according to the embodiments of the application
terminal of the operational amplifier and another ter
may have advantages over the state of the art , for example
minal of the attenuation capacitor of the attenuator .but not limited by , better out - band rejection and linearity .
2 . The wireless communication receiver according to
Further , the receiver according to the embodiments of the 20
o claim 1 , wherein the attenuator of the positive capacitive
application has negligible NF degradation because the noise
feedback loop includes a plurality of resistor elements
of the resistor attenuator ( for example , the attenuator Al coupled in series between the first output terminal and the formed by the resistor elements R1 - R3 and the capacitor second output terminal of the operational amplifier , and one
Cal in FIG . 1 ) will be divided by the gain of operational
of the resistor elements is coupled to the attenuation capaciamplifier OP1
/ OP2 .
25 tor in parallel .
Still further , the Q factor of the receiver according to the
3 . The wireless communication receiver according to
embodiments of the application is tunable by tuning the
claim 2 , wherein the first mixer includes a plurality of active
gains of the attenuator and / or the operational amplifier
elements coupled between the antenna and the first inputwherein the factor may determine the filter shape . Thus , terminal of the operational amplifier or between the antenna
the theoretical 2nd order LPF and / or the theoretical 4th order 30
and the second input terminal of the operational amplifier ,
BPF of the receiver according to the embodiments of the
the plurality of the active elements of the mixer being
application may have good filter shape by tuning the Q
controlled by a plurality of clock phases of the local oscilfactor ( . e . tuning the gains of the attenuator and / or the
lator signal , respectively . 4 . The wireless communication receiver according tooperational amplifier ) .
The receiver of the embodiments of the application may 35 Clai
vos claim 3 , further comprising :
be applied in the wireless communication system , for
a second mixer , coupled to the antenna , for performingexample but not limited by , LTE - A ( Long Term Evolution
frequency conversion on the received wireless commu
( LTE ) - Advanced ) system .
nication signal from the antenna by mixing the wirelessIt will be apparent to those skilled in the art that various
communication RF signal with the local oscillator
modifications and variations can be made to the disclosed 40signal to provide a second intermediate frequency ( IF )
embodiments . It is intended that the specification and
signal ; and
examples be considered as exemplary only , with a true scope
a second filter , coupled to the second mixer , configured to
of the disclosure being indicated by the following claims and
pass a predetermined band of frequencies of the second
their equivalents .
IF signal of the second mixer and to generate a second
What is claimed is : 45 channel signal .
1 . A wireless communication receiver , comprising :
5 . The wireless communication receiver according to
an antenna for receiving a wireless communication signal ;
claim 4 , further comprising :a first mixer , coupled to the antenna , for performing a third mixer , coupled between the antenna and the first
frequency conversion on the received wireless commu filter ; and
nication signal from the antenna by mixing the wireless 50
a fourth mixer , coupled between the antenna and the
communication signal with a local oscillator signal to
second filter ,
provide a first intermediate frequency ( IF ) signal ; and
wherein
a first filter , coupled to the first mixer , configured to pass
the first and the third mixers , coupled in parallel , are
a predetermined band of frequencies of the first IF
configured to perform performing frequency conver
signal of the first mixer and to generate a first channel 55
sion on the received wireless communication signalsignal , from the antenna by mixing the wireless communica
tion RF signal with the local oscillator signal to provide
wherein the first filter includes :
a negative feedback loop coupled to the first mixer for
the first intermediate frequency ( IF ) signal ; andperforming negative feedback loop control on the first
the second and the fourth mixers , coupled in parallel , are
IF signal from the first mixer ; and configured to perform performing frequency conver
a positive capacitive feedback loop coupled to the first
sion on the received wireless communication signal
mixer for performing positive capacitive feedback loop
