WO2005107059A1 - Systeme et procede evitant le brouillage par l'oscillateur local - Google Patents
Systeme et procede evitant le brouillage par l'oscillateur local Download PDFInfo
- Publication number
- WO2005107059A1 WO2005107059A1 PCT/IB2005/051341 IB2005051341W WO2005107059A1 WO 2005107059 A1 WO2005107059 A1 WO 2005107059A1 IB 2005051341 W IB2005051341 W IB 2005051341W WO 2005107059 A1 WO2005107059 A1 WO 2005107059A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- frequency
- mhz
- component
- phase
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B19/00—Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source
-
- 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
- H04B1/02—Transmitters
- H04B1/04—Circuits
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B27/00—Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
- H03B2200/00—Indexing scheme relating to details of oscillators covered by H03B
- H03B2200/006—Functional aspects of oscillators
- H03B2200/007—Generation of oscillations based on harmonic frequencies, e.g. overtone oscillators
Definitions
- the present invention relates to local oscillator or LO-pulling of a single die radio frequency transceiver. More particularly, the present invention relates to a system and method for at least one way to generate an LO signal for the transceiver. Most particularly, the present invention relates to a system and method for at least one way to generate the
- LO signal without pulling of a VCO of a transmitter of the transceiver.
- RF radio frequency
- LO-pulling occurs when a fraction of the transmit signal couples back to the voltage controlled oscillator (VCO) of the frequency synthesizer.
- VCO voltage controlled oscillator
- the transmit signal is modulated with the information to be transmitted, so the VCO is modulated as well.
- Zolfaghari et al propose the use of a double intermediate frequency (IF) in the up- conversion process.
- the frequency approach is selected such that no spectral components coincide with the VCO, hence circumventing the pulling problem at the cost of a complex signal path.
- Another approach is a combination of a classical direct up-conversion transmitter with an alternative LO generation.
- the frequency plan is selected so that no coinciding spectra are generated.
- the solution proposed by Darabi et al requires filtering of the mixer output signal before the signal is amplified. If no filter were applied before further amplification, the mixer output signal would be an 800 MHz square wave instead of the desired 2400 MHz signal. This results from the harmonic relation between the two mixer input signals. Hence, this approach requires more precise filtering.
- the approach proposed by Darabi is illustrated in FIG. 1 and comprises a local oscillator 100 for producing output signals LOI 107 and LOQ 108 having a desired frequency of 2400 MHz.
- Local oscillator 100 includes a VCO circuit 101, a buffer 109, a frequency divider 102 for producing 800 MHz in-phase LO component I 103 and quadrature component Q 104 signals that are half the output of the VCO, and two mixers 105 106.
- VCO circuit 101 produces a 1600 MHz signal, which is then provided via buffer 109 to frequency divider circuit 102, which produces an in-phase signal I 103, and a quadrature signal Q 104 having a frequency that is 800 MHz, or half the frequency output by the VCO 101.
- the present invention provides a system and method for generating an LO signal for a transmitter without the risk of pulling the VCO.
- the system and method of the present invention employs a filtering technique to select a desired harmonic of the VCO signal.
- the required in-phase and quadrature LO signals can be derived by means of dividers.
- the system and method of the present invention avoids any harmonic relation between the transmit signal and the VCO frequency, without generation of intermediate signals close to the VCO frequency. Hence the system and method of the present invention avoids pulling of the VCO.
- a VCO generates a sinusoidal input signal that is subsequently converted to a square wave, divided and filtered to obtain a desired harmonic in-phase I and quadrature Q signal of a pre-determined output frequency.
- a local oscillator is provided for generating signals at a desired output frequency.
- the local oscillator includes an oscillatory circuit configured to generate a first in-phase signal and a first quadrature signal at a first frequency that is lower than the desired output frequency, the first quadrature signal having a phase shift relative to the first in-phase signal; a pair of harmonic filters one coupled to receive the first in-phase signal and the other to receive the first quadrature signal and configured to obtain a pre-determined harmonic of each of these first signals; first and second transmit mixers coupled respectively to be driven by said obtained harmonic of each of said first signals.
- a desired harmonic of a square wave input signal is obtained and an in-phase and a quadrature signal are generated therefrom such that the quadrature signal is phase-shifted relative to the in-phase signal, the I and Q signals are used to drive transmit mixers.
- the oscillatory circuit is configured using an LC tank having a high Q and a small area.
- the desired harmonic is preferably the third harmonic.
- Alternative embodiments employ one filter to select the desired harmonic.
- FIG. 1 illustrates a prior art approach to avoiding LO-pulling
- FIG. 2 illustrates a first preferred embodiment of pulling-free LO generation, according to the present invention
- FIG. 3 illustrates a second preferred embodiment of pulling-free LO generation, according to the present invention
- FIG. 4 illustrates a third preferred embodiment of pulling-free LO generation, according to the present invention
- FIG. 5 illustrates an architecture of a wireless communication system whereto embodiments of the present invention are to be applied
- FIG. 6 illustrates a simplified block diagram of a wireless devices of the communication system of FIG. 5 according to an embodiment of the present invention.
- a pulling-free LO is generated as illustrated in FIG. 2.
- the VCO 201 running at 1600 MHz provides and input 212 to an IQ-generation circuit 200 that is divided in half by divider 202 to generate an in-phase LO component I 203 and a quadrature LO component Q 204, containing odd-order harmonics of 800 MHz.
- divider 202 provides and input 212 to an IQ-generation circuit 200 that is divided in half by divider 202 to generate an in-phase LO component I 203 and a quadrature LO component Q 204, containing odd-order harmonics of 800 MHz.
- the output signal of the divider 202 is a square wave 203 204, containing these odd-order harmonics.
- the system and method of the present invention applies filters 211 to the square waves 203 204 to obtain the third harmonic of these signals, and thus derives a 2400 MHz in-phase signal LOI 207 and a quadrature signal LOQ 208.
- LOI 207 and LOQ 208 are then used for driving transmit and receive mixers.
- an LC-tank Q factor of 10 is assumed and the fundamental 800 MHz component is suppressed by 28 dB.
- the resulting LO signal of 2400 MHz contains an 800 MHz spurious signal of -20 dBc.
- the first embodiment includes at least one filtering amplifier that accomplishes this matching.
- a poly-phase (LC) filter is preferred to meet the matching requirements.
- a pulling-free LO is generated as illustrated in FIG.
- the VCO 201 running at 1600 MHz provides an input 312 to an IQ-generation circuit 300 such that in the second embodiment, the third harmonic filtering 211 is done prior to the divider, preferably a divide-by-2 202.
- the quadrature relation of the I and Q signal is now determined by the divider 202, which ensures perfect quadrature.
- the 3rd harmonic filtering 211 is performed directly on a clipped (amplified) version of the VCO signal, so the LC-tank is tuned to 4800 MHz in the second embodiment.
- the higher frequency allows for a higher tank Q factor, which, as a side benefit, has a much smaller area.
- the unwanted spectrum is filtered by one of an antenna filter or a filter located in the transmit chain (both not shown).
- the regenerative properties of a divide-by-2 413 are used to generate a 1600 MHz square wave input to the third harmonic filter 211 of the second embodiment, as illustrated in FIG. 4.
- a pulling-free LO is generated by a VCO 201 that is tuned to 3200 MHz, which allows for a higher Q and a smaller area of the LC-tank, and the 3200 MHz signal is input to an IQ-generation circuit 400 in which the 3200 MHz signal is first divided and a resulting 1600 MHz square wave is input to a circuit substantially identical to the second embodiment.
- the output spectra of the I 407 and Q 408 signals are comparable to I 307 and Q 308 signals of the second embodiment, containing residual spectral components at 1600 MHz and 3200 MHz at least 26 dB down with respect to the desired 2400 MHz signal.
- the 1600 and 3200 MHz spectra are suppressed further by an antenna filter (not shown).
- further filtering is applied before the divider 202 to each of the first through third embodiments to suppress the 1600 MHz fundamental signal.
- This further filtering can be accomplished by any of: AC-coupling with a corner frequency of, say, 4 GHz between the divider output and the filter input, adding a 2nd or even a 3rd stage of filtering, and applying a 1600 MHz notch filter. Filtering is done prior to the final divide-by-2, since division of the signal creates symmetrical sidebands.
- the third embodiment has an advantage that the signal component that pulls the VCO is only present after the last divide-by-2.
- the apparatus and method of the pulling-free local oscillator of the present invention can be used for wireless personal area networks (WPANs) and local area networks (WLANs) in which an RF transmitter comprises a mixer configured to modulate the output signal of the LO with a data signal.
- WLANs local area networks
- Networks to which the present invention applies may further include GSM, Bluetooth, and DECT devices.
- FIG. 5 illustrates a representative wireless network whereto embodiments of the present invention are to be applied.
- a mixer configured to modulate the output signal of an LO with a data signal such that the pulling of the LO is avoided.
- the network illustrated in FIG. 5 is small for purposes of illustration only. In practice, most WLANs would include a much larger number of mobile transceivers incorporating the present invention.
- the low-power circuit and architecture of the LO generator of the present invention has application to a WPANs and WLANs and enables wireless devices thereof to reduce both cost and power consumption.
- the present invention introduces a filtering technique to select a desired harmonic of a VCO signal with a required in-phase and quadrature LO signal being derived by means of dividers.
- each device within the WPAN/WLAN shown in FIG. 5 may include a transceiver with an architecture that is illustrated in the block diagram of FIG. 6.
- Each device may include a controller 602 coupled to at least a transmitter 601, an LO generator 603 (200 300 400) according to the present invention, and a receiver 604.
- the transmitter 601 and the receiver 604 are coupled to an antenna 605. All may be integrated into a single chip along with other components such as the antenna.
- the controller 602 can provide adaptive programming such that, for example, the transceiver is adapted to different modulation schemes and data rates specific to various communication protocols including IEEE 802.11, Bluetooth, and any other protocol known in the art.
- the controller can program the LO generator to select a specific harmonic, it not being limited to the third harmonic. While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that the local oscillator as described herein is illustrative and various changes and modifications may be made to the local oscillator and equivalents may be substituted for elements thereof without departing from the true scope of the present invention.
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transmitters (AREA)
- Transceivers (AREA)
Abstract
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007510205A JP2007535855A (ja) | 2004-04-30 | 2005-04-25 | 発振器回路、方法、送受信機 |
EP05718801A EP1745544A1 (fr) | 2004-04-30 | 2005-04-25 | Systeme et procede evitant le brouillage par l'oscillateur local |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US56679704P | 2004-04-30 | 2004-04-30 | |
US60/566,797 | 2004-04-30 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005107059A1 true WO2005107059A1 (fr) | 2005-11-10 |
Family
ID=34965448
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2005/051341 WO2005107059A1 (fr) | 2004-04-30 | 2005-04-25 | Systeme et procede evitant le brouillage par l'oscillateur local |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1745544A1 (fr) |
JP (1) | JP2007535855A (fr) |
KR (1) | KR20070004890A (fr) |
CN (1) | CN1985436A (fr) |
WO (1) | WO2005107059A1 (fr) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006095283A2 (fr) * | 2005-03-08 | 2006-09-14 | Nxp B.V. | Dispositif electronique pour la generation d'un signal d'oscillateur local presentant une frequence egale a une partie fractionnelle d'une frequence fondamentale |
WO2009079615A1 (fr) | 2007-12-18 | 2009-06-25 | Harris Corporation | Synthétiseur de fréquences et procédé associé pour générer des signaux à large bande |
US8023922B2 (en) | 2005-02-14 | 2011-09-20 | Koninklijke Philips Electronics N.V. | Receiver for simultaneously receiving different standards |
EP2887540A1 (fr) * | 2013-12-18 | 2015-06-24 | Telefonaktiebolaget L M Ericsson (publ) | Génération de signal d'oscillateur local |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2014039143A (ja) * | 2012-08-15 | 2014-02-27 | Nec Corp | 周波数変換器及び周波数変換方法 |
US9680454B2 (en) * | 2014-10-28 | 2017-06-13 | Mediatek Inc. | Frequency tripler and local oscillator generator |
KR101902093B1 (ko) * | 2017-01-03 | 2018-09-28 | (주)에프씨아이 | Lo 생성 시스템 및 그 생성 방법 |
CN108418591A (zh) * | 2018-02-09 | 2018-08-17 | 南京中感微电子有限公司 | 无线射频发射机 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3312909A (en) * | 1964-03-26 | 1967-04-04 | Communications Patents Ltd | Variable frequency oscillation generators |
US5712596A (en) * | 1995-06-30 | 1998-01-27 | U.S. Philips Corporation | Tunable crystal oscillator with harmonic output |
US20010014596A1 (en) * | 2000-02-16 | 2001-08-16 | Tetsuya Takaki | Radio set and frequency converting method therefor |
US20020081983A1 (en) * | 2000-09-25 | 2002-06-27 | Dominique Brunel | Signal source with multiphase filter |
EP1361667A1 (fr) * | 2002-05-01 | 2003-11-12 | Sony Ericsson Mobile Communications Japan, Inc. | Dispositif de modulation-démodulation et appareil de communication sans fil |
-
2005
- 2005-04-25 WO PCT/IB2005/051341 patent/WO2005107059A1/fr not_active Application Discontinuation
- 2005-04-25 CN CNA2005800136392A patent/CN1985436A/zh active Pending
- 2005-04-25 KR KR1020067022130A patent/KR20070004890A/ko not_active Application Discontinuation
- 2005-04-25 EP EP05718801A patent/EP1745544A1/fr not_active Withdrawn
- 2005-04-25 JP JP2007510205A patent/JP2007535855A/ja not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3312909A (en) * | 1964-03-26 | 1967-04-04 | Communications Patents Ltd | Variable frequency oscillation generators |
US5712596A (en) * | 1995-06-30 | 1998-01-27 | U.S. Philips Corporation | Tunable crystal oscillator with harmonic output |
US20010014596A1 (en) * | 2000-02-16 | 2001-08-16 | Tetsuya Takaki | Radio set and frequency converting method therefor |
US20020081983A1 (en) * | 2000-09-25 | 2002-06-27 | Dominique Brunel | Signal source with multiphase filter |
EP1361667A1 (fr) * | 2002-05-01 | 2003-11-12 | Sony Ericsson Mobile Communications Japan, Inc. | Dispositif de modulation-démodulation et appareil de communication sans fil |
Non-Patent Citations (2)
Title |
---|
DARABI H ET AL: "A 2.4-GHZ CMOS TRANSCEIVER FOR BLUETOOTH", December 2001, IEEE JOURNAL OF SOLID-STATE CIRCUITS, IEEE INC. NEW YORK, US, PAGE(S) 2016-2024, ISSN: 0018-9200, XP001222524 * |
EYNDE F O ET AL: "A Fully-Integrated Zero-IF BECT Transceiver", 2000 INTERNATIONAL SOLID STATE CIRCUITS CONFERENCE, 7 February 2000 (2000-02-07), pages 138 - 139, XP010378830 * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8023922B2 (en) | 2005-02-14 | 2011-09-20 | Koninklijke Philips Electronics N.V. | Receiver for simultaneously receiving different standards |
WO2006095283A2 (fr) * | 2005-03-08 | 2006-09-14 | Nxp B.V. | Dispositif electronique pour la generation d'un signal d'oscillateur local presentant une frequence egale a une partie fractionnelle d'une frequence fondamentale |
WO2006095283A3 (fr) * | 2005-03-08 | 2008-03-06 | Nxp Bv | Dispositif electronique pour la generation d'un signal d'oscillateur local presentant une frequence egale a une partie fractionnelle d'une frequence fondamentale |
US8183941B2 (en) * | 2005-03-08 | 2012-05-22 | Koninklijke Philips Electronics N.V. | Electronic device for generating a local oscillator signal having a frequency equal to a fractional part of a fundamental frequency |
WO2009079615A1 (fr) | 2007-12-18 | 2009-06-25 | Harris Corporation | Synthétiseur de fréquences et procédé associé pour générer des signaux à large bande |
US8401493B2 (en) | 2007-12-18 | 2013-03-19 | Harris Corporation | Frequency synthesizer and related method for generating wideband signals |
US8655296B2 (en) | 2007-12-18 | 2014-02-18 | Harris Corporation | Frequency synthesizer and related method for generating wideband signals |
EP2887540A1 (fr) * | 2013-12-18 | 2015-06-24 | Telefonaktiebolaget L M Ericsson (publ) | Génération de signal d'oscillateur local |
WO2015091140A1 (fr) * | 2013-12-18 | 2015-06-25 | Telefonaktiebolaget L M Ericsson (Publ) | Génération de signaux d'oscillateur local |
Also Published As
Publication number | Publication date |
---|---|
KR20070004890A (ko) | 2007-01-09 |
CN1985436A (zh) | 2007-06-20 |
JP2007535855A (ja) | 2007-12-06 |
EP1745544A1 (fr) | 2007-01-24 |
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