WO2004015879A1 - Radio receiver with variable bandwidth if filter - Google Patents
Radio receiver with variable bandwidth if filter Download PDFInfo
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- WO2004015879A1 WO2004015879A1 PCT/US2003/022938 US0322938W WO2004015879A1 WO 2004015879 A1 WO2004015879 A1 WO 2004015879A1 US 0322938 W US0322938 W US 0322938W WO 2004015879 A1 WO2004015879 A1 WO 2004015879A1
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- 230000015572 biosynthetic process Effects 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims description 8
- 230000004044 response Effects 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims 3
- 238000012545 processing Methods 0.000 description 41
- 239000004020 conductor Substances 0.000 description 40
- 238000010586 diagram Methods 0.000 description 8
- 230000008901 benefit Effects 0.000 description 6
- 238000001228 spectrum Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 102100022717 Atypical chemokine receptor 1 Human genes 0.000 description 1
- 101000678879 Homo sapiens Atypical chemokine receptor 1 Proteins 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
- H04B1/1027—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal
- H04B1/1036—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
Definitions
- the bandwidth of the FM modulated signal change with the envelope of the modulating signal (audio signal).
- the bandwidth of the intermediate frequency stage is fixed (about 100 -KHz, single-sided band).
- the received FM signal strength is weak, it may become difficult to have good stereo separation due to excessive noise effects.
- interference from an adjacent station typically about 200 KHz away from the desired station
- FIG. 1 illustrates, in block diagram form, a radio receiver in accordance with one embodiment of the present invention
- FIG. 2 illustrates, in block diagram form, a portion of the baseband unit of FIG. 1 in more detail;
- FIG. 3 illustrates, in block diagram form, the IF filter of FIG. 2 in more detail
- FIG. 4 illustrates, in logic diagram form, the accumulative sub-band formation of FIG. 3;
- FIG. 5 illustrates, in block diagram form, the accumulative sub-band power estimator/switch control circuit of FIG. 3;
- FIG. 6 is a graphic representation of the spectrum distribution of the output of the IDFT of FIG. 3.
- FIG. 7 is a graphic representation of the spectrum distribution of the output of the accumulative sub-band formation of FIG. 3.
- FIG. 1 illustrates a radio receiver 100 in accordance with one embodiment of the present invention.
- Radio receiver 100 includes user interface 1 10 bi-directionally coupled via conductors 144 to control circuitry 112.
- Control circuitry 112 is coupled to radio frequency (RF) units 106 and 108 via conductors 142, to intermediate frequency (IF) unit 114 via conductors 140, and baseband unit 116 via conductors 138.
- RF Unit 106 is coupled to RF antenna 102 via conductor 120 and is bi-directionally coupled to IF unit 114 via conductors 124.
- RF Unit 108 is coupled to RF antenna 104 via conductor 122 and is bi-directionally coupled to IF unit 114 via conductors 126.
- IF unit 114 is coupled to baseband unit 116 via conductors 128, 130 and 132.
- Baseband unit 116 is coupled to audio processing unit 150 and data processing unit 148 via conductor 134.
- Audio processing unit 150 is coupled to amplifier and speaker 118 which provides output signals via conductor 136.
- Data processing unit 148 is bidirectionally coupled to user interface 110. Also, users may provide and receive information to and from user interface 110 via conductors 146.
- RF antennas 102 and 104 capture radio signals and provide them to RF Units 106 and 108, respectively.
- RF Units 106 and 108 translate the received radio signals to a common intermediate frequency range as dictated by the design of the radio receiver. That is, RF Units 106 and 108 may translate the frequency of the received radio signals to a lower frequency or to a higher frequency depending on the requirements of IF Unit 114 (and thus may be referred to as a "lower frequency unit” or a "higher frequency unit.")
- IF unit 114 receives the IF signals via conductors 124 and 126 and digitizes them through the use of an analog to digital converter.
- IF unit 114 also performs digital mixing to produce in-phase and quadrature digitized signals which are output via conductors 128 and 130 to base band unit 116.
- IF unit 114 is optional. That is, RF units 106 and 108 may translate the received radio signals from antennas 102 and 104 directly to base band and may include an analog to digital converter to provide the digitized base band signals directly to baseband unit 116.
- Baseband unit 116 receives the digitized radio signals from intermediate frequency unit 114 or, if the IF unit does not exist in the specific embodiment, directly from RF units 106 and 108. Baseband unit 116 performs signal conditioning, demodulation, and decoding in order to produce audio and data information via conductor 134. The processing performed by baseband unit 116 will be further described in reference to later figures. Audio information via conductor 134 may be provided to audio processing unit 150 which may be coupled to amplifier and speaker 118 to produce an audio output from receiver 100 via conductor 136. For example, this may be music played from audio speakers. Alternatively, baseband unit 116 may output data information via conductor 134 to data processing unit 148 for further processing.
- the output of data processing unit 148 may be coupled to user interface 110 to allow user interaction with the output of receiver 100.
- user interface 110 may represent a radio dial, a touch screen, monitor and keyboard, keypad, or any other suitable input/output device.
- the data information may represent text, graphics, or any other information transmitted in digital form.
- radio receiver 100 may be used for different formats of data such as AM, FM, GPS, digital T.V., T.V., digital/audio broadcast, audio broadcast, digital/video broadcast, or the like. Furthermore, receiver 100 may be designed to receive frequencies other than radio frequencies. Antennas 102 and 104 may therefore be referred to as sensors capable of sensing a variety of data formats. Furthermore, each of the sensors or antennas in the system may receive different formats of data so that, for example, one sensor may receive radio signals while other sensors may receive different types of data as listed above. Also, receiver 100 of FIG. 1 illustrates two sensors or antennas (e.g. antennas 102 and 104); however, alternate embodiments may use any number of sensors for capturing signals or information. FIG.
- IF filter 200 receives in-phase and quadrature signal pairs II, Ql and 12, Q2 via conductors 128 and 130, respectively, where II, Ql corresponds to the signal received via sensor or antenna 102 and 12, Q2 corresponds to the signal received via sensor or antenna 104.
- II and 12 represent the digitized in-phase signals while Ql and Q2 represent the digitized quadrature signals (e.g. signals that are 90 degrees out of phase as compared to the in-phase signals).
- IF filter 200 is coupled to channel processing unit 206 via conductors 202 and 204.
- Channel processing unit 206 is coupled to demodulator 212 via conductors 208 and 210, and demodulator 212 is coupled to signal processing unit 216 via conductors 214 and 215.
- Signal processing unit 216 provides audio/data information via conductor 134.
- IF filter 200, channel processing unit 206, demodulator 212, and signal processing unit 216 are coupled to control circuitry 112 via conductors 138.
- Conductors 138 may be referred to as a control bus including a variety of conductors for transferring different signals to and from units 20O, 206, 212 and 216.
- Conductor 132 may include a subset of conductors 138 or may be the full bus 138 which is provided back to intermediate frequency unit 114. Therefore, control signals received via conductor 138 may be transmitted to IF frequency unit 114 via conductor 132. Likewise, these control signals or subsets of these signals may be transmitted back to the RF units 106 and 108 via conductors 124 and 126. Alternatively, control signals may be sent directly from control circuitry 1 12 to radio frequency units 106 and 108 via conductor 142.
- IF filter 200 removes unwanted signals and noise from the desired frequency range of incoming signals II , Ql , and 12, Q2.
- IF filter 200 also suppresses adjacent channels in order to produce filtered in-phase and quadrature signal pairs II', Q2', and 12', Q2', where II', Ql' corresponds to II, Ql and 12', Q2' corresponds to 12, Q2.
- Channel processing unit 206 receives II', Ql' and 12', Q2' and combines these to produce a single combination signal Icomb, Qcomb.
- channel processing unit 206 may also provide one or both of its incoming signals such as II', Ql' or 12', Q2' directly to demodulator 212 via conductors 208 and 210 as Ibypass, Qbypass. Therefore, channel processing unit 206 provides the option of combining its incoming digitized signals or bypassing them directly to further processing units such as demodulator 212.
- Channel processing unit 206 may also provide both a combined signal such as Icomb, Qcomb and bypass signals such as Ibypass, Qbypass. However, in the case where both channels are bypassed, signals Icomb, Qcomb are used as bypass signals as well.
- Channel processing unit 206 and Ibypass, Qbypass also provide the ability to receive different types of signal formats such that one signal, such as II', Ql ', may be processed by channel processing unit 206 and output via conductor 208 while a second signal, such as 12', Q2', may be a different signal format that is directly bypassed to demodulator 212.
- Channel processing unit 206 may also perform noise reduction on the received signals. Also note that the embodiment illustrated in FIG. 2 illustrates only two signals received by IF filter 200 and channel processing unit 206.
- receiver 100 may include any number of antennas such as 102 and 104.
- each antenna would provide its own in-phase and quadrature signal pair such as II, Ql to IF filter 200.
- IF filter 200 may provide a plurality of filtered in-phase and quadrature signal pairs corresponding to each of the antennas.
- channel processing unit 206 may output a single combination signal or multiple subco binations of signals, as appropriate.
- channel processing unit 206 may provide multiple bypass signals so that more than one incoming signal may be directly bypassed to further processing units such as demodulator 212.
- Demodulator 212 receives signals Icomb, Qcomb and Ibypass, Qbypass from channel processing unit 206 and provides demodulated signals to signal processing unit 216 via conductors 214 and 215. Also, if demodulator 212 receives signals Ibypass, Qbypass, demodulator 212 may provide a demodulated Ibypass, Qbypass, also via conductors 214 and 215 to signal processing unit 216. However, as discussed above, Ibypass, Qbypass is optional. For example, in one embodiment, demodulator 212 may be an FM demodulator providing multiplex (MPX) signals corresponding to each of its incoming signals (e.g. Icomb, Qcomb and Ibypass, Qbypass).
- MPX multiplex
- demodulator 212 may be an AM demodulator or a demodulator specific to any other signal format as required by the system (e.g. receiver 100) and incoming signals II, Ql and 12, Q2.
- Signal processing unit 216 may perform further processing on the signals received via conductors 214, 215 and outputs audio/data information via conductor 134.
- Audio/data information may include just audio information, just data information or a combination of both audio and data information. This data may then be output to various different systems such as data processing systems or audio processing systems, as illustrated in FIG. 1. For example, in an FM receiver, demodulator 212 outputs an MPX signal to signal processing unit 216 as discussed above.
- signal processing unit 216 receives the MPX signal and performs stereo decoding in order to provide the proper signals to each speaker.
- the MPX signal may be decoded utilizing a pilot tone to provide left and right speaker signals in a stereo system.
- signal processing unit 216 may demodulate other sub- carrier signals (e.g. RDS or DARC) to provide further information to subsequent processing units.
- FIG. 3 illustrates, in block diagram form, IF filter 200 of FIG. 2.
- Filter portion 200 includes decimator 302, filter bank 304, accumulative sub-band formation 322, accumulative sub-band power estimator/switch control 324, and one from eight selector 326.
- IF filter 200 also includes an additional filter portion that is substantially identical to filter portion 300. The additional filter portion would be coupled between conductors 130 and 204 in FIG. 2.
- Decimator 302 has an input for receiving incoming signals II, Ql at a data rate of 480 KS/s, and an output for providing decimated signals at a data rate of 240 KS/s.
- Filter bank 304 includes polyphase subfilter 312, 314, 316, and 318, delay elements 306, 308, and 310, and 16 point inverse discrete fourier transform (IDFT) 320.
- Polyphase subfilters 312, 3 14, 316, and 318 are implemented by the filter function F(z), where
- Filter function F(z) is designed as a 16-band Nyquist type filter and has a linear phase frequency response.
- Filter bank 304 is implemented, for example, by using a technique described in "Multirate Systems and Filter Banks", by P.P. Vaidyanatha, page 165, published in 1993 by Prentice Hall. Ho ever, there are other ways to implement filter bank 304, such as for example, directly implementing a plurality of complex bandpass filters.
- the filters of the illustrated embodiment must have characteristics such that the phase linearity and flat passband characteristics of a partial or whole sum are preserved.
- Outputs Yo(n) - Yi 5 (n) are summed together by sub-band formation 320 to be equivalent to the downsampled signals corresponding to input signals II, Ql, where n is the time index.
- Each of output signals Yo(n) - Y 15 (n) is a bandpass filter having a certain predetermined passband having a center frequency 15KHz larger than the previous bandpass filter.
- Outputs Yo(n) - Yi 5 (n) are provided as inputs to accumulative sub-band formation 322.
- Sub-band formation 322 forms a set of low-pass filtered signals w 0 (n) - w 8 (n), except for signal w 9 (n) which is a bandpass filtered signal
- the passband of each subsequent low-pass filter is 15KHz larger than the preceding low-pass filter.
- Signals w 0 (n) - w 9 (n) are illustrated in FIG. 7.
- the set of output signals w 0 (n) - w 9 (n) is provided to input terminals of accumulative sub-band power estimator/switch control 324 and signals w 0 (n) - w 9 (n) are provided to inputs of one of eight selector 326.
- 16 bandpass filtered signals Yo(n) - Y ⁇ s(n) are used. However, in other embodiments, there may be more or fewer than 16 filtered signals.
- Accumulative sub-band power estimator/switch control 324 receives signals w 0 (n) - w 9 (n), and estimates the power in each signal. The power estimates are compared to predetermined threshold values and used to determine if there is adjacent station interference. If there is adjacent station interference, control signals are provided to one from eight selector 326 to select a low pass signal with a smaller passband. If no adjacent station interference is detected, then the power estimates are used to determine if the desired station is a relatively weak station requiring a different passband than if the station is relatively strong. The function of accumulative sub-band power estimator/switch control 324 will be described in more detail below in the discussion of FIG. 5. One from eight selector 326 has an output for providing II', Ql' at the 240KS/s rate.
- decimator 302 receives the digitized inphase and quadrature signals II and Ql from IP unit 114.
- Decimator 302 is implemented as a bandpass filter, provides additional stopband attenuation and allows a reduction of the sample rate from 480 KS/s (kilo samples per second) to 240 KS/s.
- the additional attenuation of the decimator allows for a simpler filter bank and the reduction in sample rate reduces the computations needed to implement filter portion 200.
- the Nyquist frequency bandwidth is partitioned into M sub-bands, where M is equal to 16. In other embodiments, M can be any number of sub-bands.
- Filter bank 304 is a filter composed of many sub-filters that are designed with particular characteristics so that the sub-bands are added together to form the whole signal. Bandwidth control of filter bank 304 is not affected by the choice of transfer function or filter. This eliminates a need to open up the bandwidth of the filter to check conditions, and thus risk allowing a degraded signal through the filter. Digital filter bank 304 decomposes the signal received on conductor 128 into multiple sub-band signals. Each sub-band filter has a linear-phase response. When some or all of the sub-band filters are summed together, a flat-passband and linear-phase bandpass filter are obtained. FIG. 4 details how the sub-bands are summed together.
- FIG. 4 illustrates, in logic diagram form, accumulative sub-band formation 322 of FIG. 3.
- Accumulative sub-band formation 322 includes a plurality of summation circuits 424, 426, 428, 430, 432, 434, 436, 438 , and 440 for summing together the complex bandpass filtered signals Yo(n) - Yi 5 (n), illustrated in FIG. 6, to create complex accumulative lowpass filtered signals w 0 (n) - w 9 (n) as illustrated in FIG. 7. Note that Yo(n) is not summed and is passed through to become Wo(n) because its center frequency is zero hertz.
- signals Y ⁇ (n), Ys(n), and Y 9 (n) are summed together to become w 9 (n).
- Y 7 1), Yg(n), and Y 9 (n) are treated as adjacent interference indicators because for FM, the first adjacent interference is about 10O - 200 KHZ from the desired signal.
- the sample rate is 240 KS/s, which means that the maximum frequency that can be recognized by the system is about 120 KHz. Therefore, after filtering by the RF section and any other prefiltering, (such as prefiltering done by decimator 302) the residual interference energy is concentrated in the highest frequency sub-bands.
- FIG. 5 illustrates, in block diagram form, accumulative sub-band power estimator/switch control circuit 324 of FIG. 3.
- Accumulative sub-band power estimator/switch control circuit 324 includes a plurality of power estimators 502, 504, 506, 508, 510, 512, 514, 516, and 518 for determining an individual estimated power for each of the accumulative lowpass filtered signals w 0 (n) - w 9 (n).
- Power estimator 502 includes a decimator 521 , absolute value calculator 520, and LPF 522. Each of the other power estimators is similar to power estimator 502.
- Switch control circuit 324 also includes multipliers 511, 513, and 515, comparators 524, 526, and 528, multiplexer 532, and decimator 533.
- the signals w 0 (n) - wg( ) are downsampled by a factor of 2. For example, w 0 (n) is downsampled using decimator 521.
- the sample rate of the power estimation may be reduced further. Note that in the illustrated embodiment, power estimates are used. In other embodiments, other parameters may be monitored, such as for example, amplitude or energy of the sub -band signals.
- an output of LPF 510 is multiplied with an interference threshold value labeled "INTERFERENCE THRESHOLD 1" by multiplier 511.
- Comparator 528 compares the output of multiplier 511 with the output of power estimators 518 to produce an interference indicator signal labeled "INTERFERENCE INDICATOR".
- the interference indicator is used as a control input for multiplexer 532. If the output of LPF 5 18 is greater than the output of multiplier 511, then interference is present.
- the output of LPF 512 is multiplied by INTERFERENCE THRESHOLD 2 and the result is compared, using comparator 524, to the output of LPF 510.
- LPF 510 is greater than the output multiplier 513, then s(n) is selected by one from eight selector 326 to be output. If the output of multiplier 513 is greater than the output of LPF 510, than W 4 1) is selected by one from eight selector 326 to be output on line 202 to channel processing unit 206 of FIG. 2.
- the output of LPF 510 is compared with an extension threshold labeled "EXTENSION THRESHOLD 1" by comparator 526 to determine if the signal of the desired station can be classified as weak. If the signal is classified as being relatively strong, than w ⁇ (n) is selected as the output by one from eight selector 326. In the case where the signal is weak, the output of LPF 510 is multiplied by an extension threshold labeled "EXTENSION THRESHOLD 2" using multiplier 515.
- FM signal bandwidth is about 75KHz (single-side), so that lowpass filtered signal Ws(z) (which has a bandwidth of about 75 KHz) contains most of the desired signal energy.
- the output of multiplier 515 is compared to the outputs of LPF 502, 504, 506, 508, and 509 by comparator 530 in sequence starting with the output of LPF 502. If the output of LPF 502 is larger than the output of multiplier 515, than w 0 (n) is selected by one from eight selector 326 as the output because, through experimentation, w 0 (n) has been determined to contain most of the energy of the desired station signal, thus providing a good representation of the desired station.
- FIG. 6 is a graphic representation of the spectrum distribution of the output of IDFT 320 of FIG. 3
- FIG. 7 a graphic representation of the spectrum distribution of the output of accumulative sub-band formation 322 of FIG. 3.
- a status circuit may be included with filter 200 to provide an indication as to which sub-band is permitted to be output and what reception quality exists.
- the invention can be used in any of a number of products, such as for example, an FM receiver, an AM receiver, a land mobile phone, a television receiver, a personal digital assistant product, a computer, a wireless communication device, a satellite receiver or an OFDM (orthogonal frequency division multiplexer) receiver.
- filter 200 By implementing filter 200 as described above, it is possible to automatically select a filter with the most appropriate passband to reject adjacent channel energy and to shrink the effective bandwidth of the filter in low frequency deviation or noisy conditions.
- filter 200 provides the above functionality with a relatively less complex implementation than some previous IF filter embodiments.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2003252109A AU2003252109A1 (en) | 2002-08-09 | 2003-07-23 | Radio receiver with variable bandwidth if filter |
JP2004527637A JP4213666B2 (en) | 2002-08-09 | 2003-07-23 | Radio receiver with variable bandwidth IF filter |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/216,335 | 2002-08-09 | ||
US10/216,335 US6957054B2 (en) | 2002-08-09 | 2002-08-09 | Radio receiver having a variable bandwidth IF filter and method therefor |
Publications (1)
Publication Number | Publication Date |
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WO2004015879A1 true WO2004015879A1 (en) | 2004-02-19 |
Family
ID=31495039
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2003/022938 WO2004015879A1 (en) | 2002-08-09 | 2003-07-23 | Radio receiver with variable bandwidth if filter |
Country Status (7)
Country | Link |
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US (1) | US6957054B2 (en) |
JP (1) | JP4213666B2 (en) |
KR (1) | KR100988448B1 (en) |
CN (1) | CN100463372C (en) |
AU (1) | AU2003252109A1 (en) |
TW (1) | TWI334702B (en) |
WO (1) | WO2004015879A1 (en) |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE60037722T2 (en) * | 2000-05-17 | 2009-01-15 | Sony Deutschland Gmbh | AM receiver |
ES2212744B2 (en) * | 2003-01-10 | 2005-03-16 | Diseño De Sistemas En Silicio, S.A. | SYNCHRONIZATION PROCEDURE IN THE DOMAIN OF TIME AND FREQUENCY OF MULTIPLE EQUIPMENT IN A TRANSMISSION SYSTEM WITH OFDM MODULATION. |
US7245882B1 (en) * | 2003-07-17 | 2007-07-17 | Atheros Communications, Inc. | Method and apparatus for a signal selective RF transceiver system |
US7206564B2 (en) * | 2003-10-16 | 2007-04-17 | Broadcom Corporation | System and method to perform adaptive channel filtering on a radio frequency burst in a cellular wireless network |
US20070184806A1 (en) * | 2004-06-07 | 2007-08-09 | Broadcom Corporation A California Corporation | System and method to perform adaptive channel filtering on a radio frequency burst in a cellular |
EP1787400A2 (en) * | 2004-08-27 | 2007-05-23 | Koninklijke Philips Electronics N.V. | Methods and apparatuses for intrasystem and intersystem sliding intermediate frequency transception |
EP1792426A4 (en) * | 2004-09-23 | 2009-04-01 | Univ California | Multiple sub-carrier selection diversity architecture and method for wireless ofdm |
US7729679B1 (en) * | 2006-06-09 | 2010-06-01 | Marvell International Ltd. | Dynamic bandwidth filter for an FM receiver |
US20080064356A1 (en) * | 2006-09-07 | 2008-03-13 | Telefonaktiebolaget Lm Ericsson (Publ) | Method of receiving wideband signal |
JP4887242B2 (en) * | 2007-08-30 | 2012-02-29 | オンセミコンダクター・トレーディング・リミテッド | Intermediate frequency filter band switching control device |
US8238866B2 (en) * | 2007-12-28 | 2012-08-07 | Astrium Limited | Filtering communications channels within telecommunications satellites |
US7692570B2 (en) * | 2008-01-16 | 2010-04-06 | Lockheed Martin Corporation | Direct RF complex analog to digital converter |
CN102193590B (en) * | 2010-03-12 | 2013-04-03 | 宏碁股份有限公司 | Portable computer and noise filtering method thereof |
US8279100B2 (en) | 2010-09-30 | 2012-10-02 | Lockheed Martin Corporation | Complex analog to digital converter (CADC) system on chip double rate architecture |
US8886208B2 (en) * | 2012-03-19 | 2014-11-11 | Qualcomm Incorporated | Method and apparatus of simultaneously monitoring GSM channels |
CN108551352A (en) * | 2018-04-17 | 2018-09-18 | 福建师范大学 | It is a kind of to can be used for interfering the ultra-wideband impulse radio preprocessor system eliminated |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5465410A (en) * | 1994-11-22 | 1995-11-07 | Motorola, Inc. | Method and apparatus for automatic frequency and bandwidth control |
EP0887944A2 (en) * | 1997-06-27 | 1998-12-30 | Ford Global Technologies, Inc. | Digital processing radio receiver |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5244869A (en) * | 1990-10-23 | 1993-09-14 | Westinghouse Electric Corp. | Superconducting microwave frequency selective filter system |
TW263640B (en) * | 1992-06-26 | 1995-11-21 | Philips Electronics Nv | |
DE4319457C2 (en) * | 1993-06-11 | 1997-09-04 | Blaupunkt Werke Gmbh | Circuit arrangement for adjacent channel detection and suppression in an FM radio receiver |
US5745187A (en) * | 1994-02-10 | 1998-04-28 | U.S. Philips Corporation | Method and apparatus for combating co-channel NTSC interference for digital TV transmission using a bank of rejection filters |
PL315915A1 (en) * | 1994-12-19 | 1996-12-09 | Motorola Inc | Method of and apparatus for reducing interferences in a communication system |
US5838675A (en) * | 1996-07-03 | 1998-11-17 | The United States Of America As Represented By The Secretary Of The Navy | Channelized receiver-front-end protection circuit which demultiplexes broadband signals into a plurality of different microwave signals in respective contiguous frequency channels, phase adjusts and multiplexes channels |
US5867479A (en) * | 1997-06-27 | 1999-02-02 | Lockheed Martin Corporation | Digital multi-channel demultiplexer/multiplex (MCD/M architecture) |
US6658245B2 (en) * | 2001-03-28 | 2003-12-02 | Motorola, Inc. | Radio receiver having a dynamic bandwidth filter and method therefor |
-
2002
- 2002-08-09 US US10/216,335 patent/US6957054B2/en not_active Expired - Fee Related
-
2003
- 2003-07-23 JP JP2004527637A patent/JP4213666B2/en not_active Expired - Fee Related
- 2003-07-23 CN CNB038188406A patent/CN100463372C/en not_active Expired - Fee Related
- 2003-07-23 AU AU2003252109A patent/AU2003252109A1/en not_active Abandoned
- 2003-07-23 KR KR1020057001966A patent/KR100988448B1/en not_active IP Right Cessation
- 2003-07-23 WO PCT/US2003/022938 patent/WO2004015879A1/en active Application Filing
- 2003-08-06 TW TW092121513A patent/TWI334702B/en not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5465410A (en) * | 1994-11-22 | 1995-11-07 | Motorola, Inc. | Method and apparatus for automatic frequency and bandwidth control |
EP0887944A2 (en) * | 1997-06-27 | 1998-12-30 | Ford Global Technologies, Inc. | Digital processing radio receiver |
Also Published As
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KR20050056949A (en) | 2005-06-16 |
TWI334702B (en) | 2010-12-11 |
CN100463372C (en) | 2009-02-18 |
TW200405676A (en) | 2004-04-01 |
US20040029548A1 (en) | 2004-02-12 |
US6957054B2 (en) | 2005-10-18 |
JP4213666B2 (en) | 2009-01-21 |
CN1675844A (en) | 2005-09-28 |
JP2005536109A (en) | 2005-11-24 |
KR100988448B1 (en) | 2010-10-18 |
AU2003252109A1 (en) | 2004-02-25 |
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