U.S. patent application number 13/852197 was filed with the patent office on 2013-08-29 for on-demand signal notching in a receiver.
This patent application is currently assigned to Broadcom Corporation. The applicant listed for this patent is Broadcom Corporation. Invention is credited to Ahmadreza Rofougaran, Maryam Rofougaran.
Application Number | 20130225109 13/852197 |
Document ID | / |
Family ID | 41267260 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130225109 |
Kind Code |
A1 |
Rofougaran; Ahmadreza ; et
al. |
August 29, 2013 |
On-Demand Signal Notching in a Receiver
Abstract
Aspects of a method and system for on-demand signal notching in
a receiver. In this regard, signal strength measurements of a
received signal may enable detection of unwanted signal
component(s) and one or more filters in an on-chip receiver may be
configured in response to the measurements. The filter(s) may
additionally be configured based on power consumption of the
filter(s). Signal measurements and/or the corresponding
configuration may be performed real-time. The filter(s) may be
configured such that a notch in a frequency response of the
filter(s) is centered at or near the unwanted component. In this
manner, the unwanted component(s) may be filtered out. The
filter(s) may be configured, for example, by switching one or more
filter stages and/or components into and/or out of a signal path
and/or by tuning one or more variable circuit elements within the
filter(s).
Inventors: |
Rofougaran; Ahmadreza;
(Newport Coast, CA) ; Rofougaran; Maryam; (Rancho
Palos Verdes, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Broadcom Corporation; |
|
|
US |
|
|
Assignee: |
Broadcom Corporation
Irvine
CA
|
Family ID: |
41267260 |
Appl. No.: |
13/852197 |
Filed: |
March 28, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12116397 |
May 7, 2008 |
8417204 |
|
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13852197 |
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Current U.S.
Class: |
455/307 |
Current CPC
Class: |
H04B 1/1036 20130101;
H04B 1/10 20130101 |
Class at
Publication: |
455/307 |
International
Class: |
H04B 1/10 20060101
H04B001/10 |
Claims
1-27. (canceled)
28. A signal processing system comprising: a circuit operable to
detect an unwanted component of a received signal in a receiver;
said circuit being operable to configure a filter in said receiver
such that a notch in a frequency response of said filter is
centered by adjusting one or more poles and zeros near said
unwanted component.
29. The signal processing system of claim 28, wherein said circuit
is operable to detect said unwanted component by a comparison of a
strength of said received signal to one or more thresholds.
30. The signal processing system of claim 29, wherein said circuit
is operable to determine said one or more thresholds based on a
signal to noise ratio of said received signal.
31. The signal processing system of claim 29, wherein said circuit
is operable to determine said one or more thresholds based on a
dynamic range of said received signal.
32. The signal processing system of claim 28, wherein said unwanted
components is in-band.
33. The signal processing system of claim 28, wherein said unwanted
components is out-of-band.
34. The signal processing system of claim 28, wherein said circuit
is operable to configure said filter by switching one or more
stages of said filter into a signal path.
35. The signal processing system of claim 28, wherein said circuit
is operable to configure said filter by switching one or more
stages of said filter out of a signal path.
36. The signal processing system of claim 28, wherein said circuit
is operable to configure said filter by tuning one or more variable
circuit elements within said filter.
37. A machine-readable storage having stored thereon a computer
program having at least one code section for signal processing,
said at least one code section being executable by a machine for
causing said machine to: detect an unwanted component of a received
signal in a receiver; configure a filter in said receiver such that
a notch in a frequency response of said filter is centered by
adjusting one or more poles and zeros near said unwanted
component.
38. The machine-readable storage of claim 37, wherein said at least
one code section comprises code for filtering said unwanted
component of said received signal by said filter.
39. The machine-readable storage of claim 37, wherein said at least
one code section comprises code for configuring said filter in said
receiver based on a power consumption of said filter.
40. The machine-readable storage of claim 37, wherein said at least
one code section comprises code for detecting said unwanted
component by a comparison of a strength of said received signal to
one or more thresholds.
41. The machine-readable storage of claim 40, wherein said at least
one code section comprises code for determining said one or more
thresholds based on a signal to noise ratio of said received
signal.
42. The machine-readable storage of claim 40, wherein said at least
one code section comprises code for determining said one or more
thresholds based on a dynamic range of said received signal.
43. The machine-readable storage of claim 37, wherein said unwanted
components is in-band.
44. The machine-readable storage of claim 37,wherein said unwanted
components is out-of-band.
45. The machine-readable storage of claim 37, wherein said at least
one code section comprises code for configuring said filter by
switching one or more stages of said filter into a signal path.
46. The machine-readable storage of claim 37, wherein said at least
one code section comprises code for configuring said filter by
switching one or more stages of said filter out of a signal
path.
47. The machine-readable storage of claim 37, wherein said at least
one code section comprises code for configuring said filter by
tuning one or more variable circuit elements within said filter.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY
REFERENCE
[0001] This patent application makes reference to: [0002] U.S.
patent application Ser. No. 11/954,962 (Attorney Docket No.
19247US01) filed on Dec. 12, 2007; [0003] U.S. patent application
Ser. No. 11/955,064 (Attorney Docket No. 19254US01) filed on Dec.
12, 2007; and [0004] U.S. patent application Ser. No. ______
(Attorney Docket No. 19249US01) filed on even date herewith.
[0005] Each of the above stated applications is hereby incorporated
herein by reference in its entirety.
FIELD OF THE INVENTION
[0006] Certain embodiments of the invention relate to signal
processing. More specifically, certain embodiments of the invention
relate to a method and system for on-demand signal notching in a
receiver.
BACKGROUND OF THE INVENTION
[0007] Mobile communications have changed the way people
communicate and mobile phones have been transformed from a luxury
item to an essential part of every day life. The use of mobile
phones is today dictated by social situations, rather than hampered
by location or technology. While voice connections fulfill the
basic need to communicate, and mobile voice connections continue to
filter even further into the fabric of every day life, the mobile
Internet is the next step in the mobile communication revolution.
The mobile Internet is poised to become a common source of everyday
information, and easy, versatile mobile access to this data will be
taken for granted.
[0008] As the number of electronic devices enabled for wireline
and/or mobile communications continues to increase, significant
efforts exist with regard to making such devices more power
efficient. For example, a large percentage of communications
devices are mobile wireless devices and thus often operate on
battery power. Additionally, transmit and/or receive circuitry
within such mobile wireless devices often account for a significant
portion of the power consumed within these devices. Moreover, in
some conventional communication systems, transmitters and/or
receivers are often power inefficient in comparison to other blocks
of the portable communication devices. Accordingly, these
transmitters and/or receivers have a significant impact on battery
life for these mobile wireless devices.
[0009] Additionally, as the number of wireless devices and wireless
communications standards increase, commonly used frequency bands
are becoming increasingly congested with wireless traffic. In this
regard, designing devices that can reliably operate in such noisy
frequency bands is becoming increasingly difficult and costly.
Accordingly, efforts exist to develop wireless technologies which
operate at higher, less congested frequencies.
[0010] For example, in 2001, the Federal Communications Commission
(FCC) designated a large contiguous block of 7 GHz bandwidth for
communications in the 57 GHz to 64 GHz spectrum. This frequency
band may be used by the spectrum users on an unlicensed basis, that
is, the spectrum is accessible to anyone, subject to certain basic,
technical restrictions such as maximum transmission power and
certain coexistence mechanisms. The communications taking place in
this band are often referred to as `60 GHz communications`. With
respect to the accessibility of this part of the spectrum, 60 GHz
communications is similar to other forms of unlicensed spectrum
use, for example Wireless LANs or Bluetooth in the 2.4 GHz ISM
bands. However, communications at 60 GHz may be significantly
different in aspects other than accessibility. In this regard,
there may be certain drawbacks associated with 60 GHz
communications. For example, 60 GHz signals may provide markedly
different communications channel and propagation characteristics.
In this regard, 60 GHz radiation is partly absorbed by oxygen in
the air. Accordingly, 60 GHz communications suffer from increased
attenuation with distance as compared to, for example, 2.4 GHz. On
the other hand, there may be advantages associated with 60 GHz
communications. For example, since a very large bandwidth of 7 GHz
is available, very high data rates may be achieved.
[0011] Shrinking features size of CMOS processes, for example, is
one factor enabling development products and technologies for 60
GHz communications. However, even when fabricated on the smallest
processes, conventional methods and circuit topologies are often
unable to realize signal generation circuits which can generate
signals sufficiently high in frequency to enable technologies such
as 60 GHz communications.
[0012] Further limitations and disadvantages of conventional and
traditional approaches will become apparent to one of skill in the
art, through comparison of such systems with some aspects of the
present invention as set forth in the remainder of the present
application with reference to the drawings.
BRIEF SUMMARY OF THE INVENTION
[0013] A system and/or method is provided for on-demand signal
notching in a receiver, substantially as shown in and/or described
in connection with at least one of the figures, as set forth more
completely in the claims.
[0014] These and other advantages, aspects and novel features of
the present invention, as well as details of an illustrated
embodiment thereof, will be more fully understood from the
following description and drawings.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0015] FIG. 1A is a block diagram illustrating an exemplary
wireless device, in accordance with an embodiment of the
invention.
[0016] FIG. 1B is a block diagram of an exemplary receiver with
on-demand filtering, in accordance with an embodiment of the
invention.
[0017] FIG. 1C is a block diagram of an exemplary configurable
filter, in accordance with an embodiment of the invention.
[0018] FIG, 2A is a diagram illustrating an exemplary frequency
spectrum of signals arriving at a receiver with on-demand signal
notching, in accordance with an embodiment of the invention.
[0019] FIG. 2B is a diagram that illustrates introduction of a
notch in a filter response to attenuate a blocker (interference)
signal, in accordance with an embodiment of the invention.
[0020] FIG. 2C is a diagram that illustrates adjustment of a
frequency of a notch to attenuate a blocker (interference) signal,
in accordance with an embodiment of the invention.
[0021] FIG. 3 is a flow chart illustrating exemplary steps for
on-demand signal notching in a receiver, in accordance with an
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Certain embodiments of the invention may be found in a
method and system for on-demand signal notching in a receiver. In
accordance with various embodiments of the invention, signal
strength measurements of a received signal may enable detection of
unwanted signal component(s), and one or more filters in an on-chip
receiver may be configured in response to the measurements. The
filter(s) may additionally be configured based on power consumption
of the filter(s). Signal measurements and/or the corresponding
configuration may be performed dynamically and/or in real-time. The
filter(s) may be configured such that a notch in a frequency
response of the filter(s) is centered at or near the unwanted
component. In this manner, the unwanted component(s) may be
filtered out. Unwanted components, which may be in-band and/or
out-of-band, may be detected based on, for example, a comparison of
the measured strength to one or more thresholds, a signal to noise
ratio of the received signal, and/or a dynamic range of the
received signal. The filter(s) may be configured, for example, by
switching one or more filter stages and/or components into and/or
out of a signal path and/or by tuning one or more variable circuit
elements within the filter(s). In various embodiments of the
invention, received signals may comprise a frequency at or near the
industrial scientific and medical band centered at 61.25 GHz.
[0023] FIG. 1A is a block diagram illustrating an exemplary
wireless device, in accordance with an embodiment of the invention.
Referring to FIG. 1A, there is shown a wireless device 20 that may
comprise an RF receiver 23a, an RF transmitter 23b, a digital
baseband processor 29, a processor 25, and a memory 27. A receive
antenna 21a may be communicatively coupled to the RF receiver 23a.
A transmit antenna 21b may be communicatively coupled to the RF
transmitter 23b. The wireless device 20 may transmit and receive
information utilizing high data rate, line-of-site communications
operating at extremely high frequency (EHF) such as the ISM band
centered at 61.25 GHz.
[0024] The RF receiver 23a may comprise suitable logic, circuitry,
and/or code that may enable processing of received RF signals. The
RF receiver 23a may enable receiving RF signals in a plurality of
frequency bands. For example, the RF receiver 23a may enable
receiving signals in extremely high frequency (e.g., 60 GHz) bands.
The receiver 23a may be as described with respect to FIG. 1A, for
example. In this regard, the receiver 23a may be enabled to
receive, filter, amplify, down-convert, and/or perform analog to
digital conversion. Moreover, filtering in the receiver 23a may be
dynamically controlled, and thus power efficiency of the receiver
23a may be improved over conventional receivers. In various
embodiments of the invention, the wireless device 20 may comprise a
plurality of the receivers 23a and may thus support multiple
frequency bands and or simultaneous reception of signals in the
same frequency band. In various embodiments of the invention, the
RF receiver 23a may down convert a received RF signal to baseband
or to an intermediate frequency (IF). Additionally, the receiver
23a may perform quadrature down-conversion where in-phase
components and quadrature phase components may be processed in
parallel.
[0025] The digital baseband processor 29 may comprise suitable
logic, circuitry, and/or code that may enable processing and/or
handling of baseband signals. In this regard, the digital baseband
processor 29 may process or handle signals received from the RF
receiver 23a and/or signals to be transferred to the RF transmitter
23b, when the RF transmitter 23b is present, for transmission to
the network. The digital baseband processor 29 may also provide
control and/or feedback information to the RF receiver 23a and to
the RF transmitter 23b based on information from the processed
signals. In this regard, the baseband processor 29 may provide a
control signal to one or more of SSI 104, the LNA 110, the mixer
112, the filter 114 (and possibly 106 and 108), and/or the ADC 116.
The digital baseband processor 29 may communicate information
and/or data from the processed signals to the processor 25 and/or
to the memory 27. Moreover, the digital baseband processor 29 may
receive information from the processor 25 and/or to the memory 27,
which may be processed and transferred to the RF transmitter 23b
for transmission to the network.
[0026] The RF transmitter 23b may comprise suitable logic,
circuitry, and/or code that may enable processing of RF signals for
transmission. The RF transmitter 23b may enable transmission of RF
signals in a plurality of frequency bands. For example, the RF
transmitter 23b may enable transmitting signals in extremely high
frequency (EHF) bands such as the ISM centered at 61.25 GHz. Each
frequency band supported by the RF transmitter 23b may have a
corresponding front-end circuit for handling amplification and up
conversion operations, for example. In this regard, the RF
transmitter 23b may be referred to as a multi-band transmitter when
it supports more than one frequency band. In another embodiment of
the invention, the wireless device 20 may comprise more than one RF
transmitter 23b, wherein each of the RF transmitter 23b may be a
single-band or a multi-band transmitter. In various embodiments of
the invention, the RF transmitter 23b may perform direct up
conversion of the baseband signal to an RF signal. In some
instances, the RF transmitter 23b may enable digital-to-analog
conversion of the baseband signal components received from the
digital baseband processor 29 before up conversion. In other
instances, the RF transmitter 23b may receive baseband signal
components in analog form.
[0027] The processor 25 may comprise suitable logic, circuitry,
and/or code that may enable control and/or data processing
operations for the wireless device 20. The processor 25 may be
utilized to control at least a portion of the RF receiver 23a, the
RF transmitter 23b, the digital baseband processor 29, and/or the
memory 27. In this regard, the processor 25 may generate at least
one signal for controlling operations within the wireless device
20. In this regard, the processor 25 may provide a control signal
to one or more of SSI 104, the LNA 110, the mixer 112, the filter
114 (and possibly 106 and 108), and/or the ADC 116. The processor
25 may also enable executing of applications that may be utilized
by the wireless device 20. For example, the processor 25 may
execute applications that may enable displaying and/or interacting
with content received via EHF communications.
[0028] The memory 27 may comprise suitable logic, circuitry, and/or
code that may enable storage of data and/or other information
utilized by the wireless device 20. For example, the memory 27 may
be utilized for storing processed data generated by the digital
baseband processor 29 and/or the processor 25. The memory 27 may
also be utilized to store information, such as configuration
information, that may be utilized to control the operation of at
least one block in the wireless device 20. For example, the memory
27 may comprise information necessary to configure the RF receiver
23a to enable receiving signals at various signal levels and in the
presence of varying amounts of interference. In this regard, the
memory may store control and/or configuration information for one
or more of the SSI 104, the LNA 110, the mixer 112, the filter 114
(and possibly 106 and 108), and/or the ADC 116.
[0029] FIG. 1B is a block diagram of an exemplary receiver with
on-demand signal notching, in accordance with an embodiment of the
invention. Referring to FIG. 1B the receiver 23a may comprise a
signal strength indicator (SSI) 104, filters 106, 108, and 114, low
noise amplifier (LNA) 110, mixer 112, and analog-to-digital
converter (ADC) 116. In various embodiments of the invention, the
components of the receiver 423a may reside on a common substrate,
such as a silicon die. In this regard, the receiver 423a may be
referred to as a system on chip.
[0030] The SSI 104 may comprise suitable logic, circuitry, and/or
code that may enable determining signal strength. In this regard,
the SSI 104 may, for example, be enabled to measure current,
voltage and/or power of the signal 103 and/or 111. Additionally,
the SSI 104 may be enabled to generate one or more control signals
105, which, in various embodiments of the invention, may be coupled
to one or more of the filters 106, 108, and 114. In various
embodiments of the invention, the signal 105 may be a digital
and/or analog signal representation of the current, voltage, and/or
power of the signal 103 and/or 111.
[0031] The filter 106 may comprise suitable logic, circuitry,
and/or code for attenuating undesired frequencies to a greater
extent than desired frequencies. In this regard, the filter 106 may
have, for example, a bandpass frequency response. The filter 108
may be tunable such that a bandwidth and/or center frequency
characterizing the frequency response of the filter may be
adjustable. In this manner, the filter 106 may be controlled such
that the SSI 104 may perform measurements of desired frequencies,
bandwidths, etc. Additionally, the filter 106 may be configured
based on measurements performed by the SSI 104. In this regard, one
or more components and/or stages of the filter 106 may be switched
into and/or out a signal path of the filter 108 to control, for
example, a gain, a bandwidth, a center frequency, and/or a passband
and/or stopband response. Exemplary passband and/or stopband
responses comprise Butterworth, Chebyshev, Cauer, Bessel, of the
filter 106.
[0032] The filter 108 may comprise suitable logic, circuitry,
and/or code for attenuating undesired frequencies to a greater
extent than desired frequencies. The filter 108 may be configurable
such that one or more poles and/or zeros characterizing the
frequency response of the filter 108 may be added, removed, and/or
adjusted. In this manner, by adding, removing, or adjusting poles
and/or zeros characterizing the frequency response of the filter
108, aspects of the invention may enable tuning the receiver 423a
to a desired frequency (e.g. 60 GHz) and attenuating interference
and/or noise.
[0033] The filter 114 may comprise suitable logic, circuitry,
and/or code for attenuating undesired frequencies to a greater
extent than desired frequencies. In this regard, the filter 114 may
have, for example, a bandpass frequency response. The filter 114
may be configurable such that one or more poles and/or zeros
characterizing the frequency response of the filter 114 may be
added, removed, and/or adjusted. In this manner, by adding,
removing, or adjusting zeros characterizing the frequency response
of the filter 108, aspects of the invention may enable rejecting
undesired inter-modulation products output by the mixer 112 while
passing desired inter-modulation products,
[0034] The mixer 112 may comprise suitable logic, circuitry, and/or
code that may enable generation of inter-modulation products
resulting from the mixing of a received RF signal and a local
oscillator (LO). The frequency of the LO signal may be determined
based on the desired frequency/channel to be received. In this
regard, the mixer 112 may enable down-converting, for example, RF
signals of a range of frequencies to a fixed intermediate frequency
(IF) or directly to baseband.
[0035] The LNA 110 may comprise suitable logic, circuitry, and/or
code that may enable buffering and/or amplification of received RF
signals. In this regard, the gain of the LNA 110 may be adjustable
to enable reception of signals of varying strength. Accordingly,
the output 111 of the LNA 110 may be measured (e.g., by the SSI
104) and the gain of the LNA 110 may be adjusted to maintain the
signal 111 within determined limits.
[0036] The ADC 116 may comprise suitable logic, circuitry, and/or
code that may enable conversion of analog signals to a digital
representation. In this regard, the ADC 116 may, for example,
sample and quantize analog signal 115 at times specified by a
sample clock. Accordingly, the ADC 116 may receive one or more
control signals from, for example, a processor and/or a clock
generator.
[0037] In operation, an RF signal received by the antenna 21a
and/or the LNA output 111 may be measured real-time to determine
signal strength of in-band and/or out-of-band signals. In this
regard, in-band may refer to signals within a passband of the
filter 108 while out-of-band signals may fall in a stopband of the
filter 108. The filter 106 may be adjusted and/or tuned and
measurements may be taken at various frequencies and/or bandwidths
in order to determine the in-band and/or out-of-band signal
strengths. Alternatively, the SSI 104 may be enabled to determine
other exemplary characteristics such as signal to noise ratio,
dynamic range, etc.) of the received signal by, for example,
performing a fast Fourier transform analysis of the signal 103
and/or 111.
[0038] FIG. 1C is a block diagram of an exemplary configurable
filter, in accordance with an embodiment of the invention.
Referring to FIG. 1C there is shown a filter 150 comprising a
plurality of filter stages and/or components 152 and plurality of
switching elements 154.
[0039] Each of the filter stages and/or components 152 may comprise
suitable logic, circuitry, and/or code for affecting the response
of the filter 150. Additionally, each of the stages and/or
components 152 may be tunable or otherwise configurable via one or
more signals 205. For example, each stage and/or components 152 may
comprise one or more variable capacitors, inductors, and/or
resistors, which may be controlled via one or more signals 157
generated by the configuration block 156. Furthermore, each stage
and/or components 152 or a portion thereof may be powered down when
not switched into a signal path of the receiver 23a.
[0040] The configuration block 156 may comprise suitable logic,
circuitry, and/or code for configuring the filter 150 based on the
signal(s) 205 generated by the SSI 104. In this regard, the
configuration block 156 may generate one or more signals 157 for
tuning the stages and/or components 152 and for switching the
stages and/or components 152 in and/or out of the signal path via
the switching elements 152 based on the signal(s) 105 generated by
the SSI 104. In this manner, the filter 150 may be configured
real-time in response to measurements of signals received by the
receiver 23a.
[0041] In operation, switching one or more of the stages and/or
components 152 into and/or out of the signal path, via the
switching elements 154, may enable adding or removing poles and/or
zeros from the frequency response of the filter 150. Additionally,
tuning the stages and/or components 152 that are switched into the
signal path may enable adjusting the frequency of poles and/or
zeros. For example, in instances where a strong signal component
may be measured at a frequency other than a desired frequency, then
various aspects of the invention may enable adding one or more
poles and/or zeros to the filter 150 and/or adjusting the frequency
of one or more poles and/or zeros such that a notch in the response
of the filter may attenuate the undesired signal component. In this
regard, a notch may be introduced at an undesired frequency in
instances that measured signal strength at the undesired frequency
may be greater than a threshold. In this regard, a threshold(s) to
which the signal measurement may be compared may be dynamically
determined based on characteristics, such as dynamic range and
signal to noise ratio, of a received signal.
[0042] FIG. 2 is a diagram illustrating an exemplary frequency
spectrum of signals arriving at a receiver with on-demand signal
notching, in accordance with an embodiment of the invention.
Referring to FIG, 2, there is shown a signal 200 comprising a
desired component 201, in-band blocker (interference) signal
component 203, and out-of-band blocker (interference) signal
component 205. Accordingly, the SSI 104 may be enabled to measure
the strength of the signal components 201, 203, and/or 205 and
adjust the frequency response of one or more filters in the
receiver 23a in response to the measurements. In this manner, the
receiver 23a may be configured dynamically and/or in real-time in
response to characteristics of signals it is receiving. In an
exemplary embodiment of the invention, the signal component 201 may
be a desired channel, the signal component 205 may be an adjacent
channel, and the signal component 203 may be interference from, for
example, a different technology or wireless standard.
[0043] FIG. 2B is a diagram that illustrates introduction of a
notch in a filter response to attenuate a blocker (interference)
signal, in accordance with an embodiment of the invention.
Referring to FIG. 2B there is shown two filtering operations 250
and 260 in which a desired signal 201 and an undesired signal 251
may be input to a filter such as the filter 108 or 114.
[0044] For the filtering operation 250, the filter may have
frequency response 252. Consequently, because f.sub.D and f.sub.B
are both in the passband of the response 252, the undesired signal
251 may be present at the output of the filter.
[0045] Accordingly, various aspects of the invention may enable
configuring the filter such that the frequency response of the
filter may be altered from the frequency response 252 to the
frequency response 254. In this regard, one or more poles and/or
zeros may be added, removed, and/or adjusted in frequency to create
a notch centered at f.sub.B.
[0046] Thus, for the filtering operation 260, f.sub.D may be in a
passband of the frequency response 254 and f.sub.B may be notched.
Consequently, the undesired signal 251 may be attenuated at the
output of the filter.
[0047] FIG. 2C is a diagram that illustrates adjustment of a
frequency of a notch to attenuate a blocker (interference) signal,
in accordance with an embodiment of the invention. Referring to
FIG. 2C there is shown two filtering operations 270 and 280 in
which a desired signal 201 and an undesired signal 251 may be input
to a filter such as the filter 108 or 114.
[0048] For the filtering operation 270, the filter may have
frequency response 256. Consequently, because the notch in the
frequency response may not be centered on f.sub.B, the undesired
signal 251 may still be present at the output of the filter.
[0049] Accordingly, aspects of the invention may enable configuring
the filter such that the frequency response may be altered from the
frequency response 256 to the frequency response 258. In this
regard, one or more poles and/or zeros may be added, removed,
and/or adjusted in frequency to adjust the notch such that it may
be centered at f.sub.B.
[0050] Thus, for the filtering operation 280, f.sub.D may be in a
passband of the frequency response 258 and f.sub.B may be notched.
Consequently, the undesired signal 251 may be attenuated at the
output of the filter.
[0051] FIG. 3 is a flow chart illustrating exemplary steps for
on-demand signal notching in a receiver, in accordance with an
embodiment of the invention. Referring to FIG. 3 the exemplary
steps may begin with start step 302 when signals may be received by
the antenna 21 a. Subsequent to step 302, the exemplary steps may
advance to step 304. In step 304, the filter 106 may be tuned to
control which frequencies may be measured by the SSI 104. For
example, the filter 106 may sweep one or more frequency bands to
characterize the environment in which the receiver 23a may be
operating. Subsequent to step 304, the exemplary steps may advance
to step 306.
[0052] In step 306, the SSI 104 may provide a measure of the signal
strength of the signal 103 and/or 111. Accordingly, the signal 105
generated by the SSI 104 may be based, at least in part, on the
results of the measurement of the signal 103 and/or 111. For
example, the signal 105 may be a DC voltage which may be compared
to one or more reference voltages to configure the filters 108 and
114. In another embodiment of the invention, the signal 105 may be
a periodic signal and a characteristic(s) such as phase, frequency,
duty cycle, etc. of the signal 105 may, at least in part, be
utilized to configure the filters 108 and 114. Subsequent to step
306, the exemplary steps may advance to the step 308.
[0053] In step 308, the filters 108 and 114 may be configured based
on the signal(s) 105. In this regard, the filter 108 may be
configured to notch out strong undesired signal components in a
received signal. Similarly, the filter 114 may be configured to
notch out strong undesired signals output by the mixer 112.
[0054] Subsequent to step 308, the exemplary steps may return to
step 306. In this regard, the process of monitoring signal levels
and configuring the filters 108 and 114 to notch out undesired
signal components may be based on periodic or continuous feedback
to improve performance of the receiver 23a.
[0055] Exemplary aspects of a method and system for on-demand
signal notching in a receiver. In this regard, signal strength
measurements of a received signal may enable detection of unwanted
signal component(s) 203 and/or 205 and one or more filters 150 in
an on-chip receiver 23a may be configured in response to the
measurements. The filter(s) 150 may additionally be configured
based on power consumption of the filter(s) 150. Signal
measurements and/or the corresponding configuration may be
performed real-time. The filter(s) 150 may be configured such that
a notch in a frequency response of the filter(s) 150 is centered at
or near the unwanted component. In this manner, the unwanted
component(s) may be filtered out. Unwanted components, which may be
in-band signals 203 and/or out-of-band signal 205, may be detected
based on, for example, a comparison of the measured strength to one
or more thresholds, a signal to noise ratio of the received signal,
and/or a dynamic range of the received signal. The filter(s) 150
may be configured, for example, by switching one or more filter
stages and/or components 152 into and/or out of a signal path
and/or by tuning one or more variable circuit elements within the
filter(s). In various embodiments of the invention, received
signals may be of frequency at or near the industrial scientific
and medical band centered at 61.25 GHz.
[0056] Another embodiment of the invention may provide a
machine-readable storage, having stored thereon, a computer program
having at least one code section executable by a machine, thereby
causing the machine to perform the steps as described herein for
on-demand signal notching in a receiver.
[0057] Accordingly, the present invention may be realized in
hardware, software, or a combination of hardware and software. The
present invention may be realized in a centralized fashion in at
least one computer system, or in a distributed fashion where
different elements are spread across several interconnected
computer systems. Any kind of computer system or other apparatus
adapted for carrying out the methods described herein is suited. A
typical combination of hardware and software may be a
general-purpose computer system with a computer program that, when
being loaded and executed, controls the computer system such that
it carries out the methods described herein.
[0058] The present invention may also be embedded in a computer
program product, which comprises all the features enabling the
implementation of the methods described herein, and which when
loaded in a computer system is able to carry out these methods.
Computer program in the present context means any expression, in
any language, code or notation, of a set of instructions intended
to cause a system having an information processing capability to
perform a particular function either directly or after either or
both of the following: a) conversion to another language, code or
notation; b) reproduction in a different material form.
[0059] While the present invention has been described with
reference to certain embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted without departing from the scope of the present
invention. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the present
invention without departing from its scope. Therefore, it is
intended that the present invention not be limited to the
particular embodiment disclosed, but that the present invention
will include all embodiments falling within the scope of the
appended claims.
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