WO1996027948A2 - Method and apparatus for controlling frequency of a multi-channel transmitter - Google Patents
Method and apparatus for controlling frequency of a multi-channel transmitter Download PDFInfo
- Publication number
- WO1996027948A2 WO1996027948A2 PCT/US1996/002847 US9602847W WO9627948A2 WO 1996027948 A2 WO1996027948 A2 WO 1996027948A2 US 9602847 W US9602847 W US 9602847W WO 9627948 A2 WO9627948 A2 WO 9627948A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- frequency
- signal
- discriminator
- thermally stable
- emitted
- Prior art date
Links
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
- H03B21/00—Generation of oscillations by combining unmodulated signals of different frequencies
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
- H03J7/02—Automatic frequency control
-
- 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
- H04B1/0483—Transmitters with multiple parallel paths
-
- 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
- H04B2001/0491—Circuits with frequency synthesizers, frequency converters or modulators
Definitions
- U.S. Patent 4,694,260 discloses a microwave frequency discriminator for transforming a frequency modulated signal into a low frequency demodulated signal, wherein the discriminator is used with microwaves.
- An oscillating circuit has a frequency controlled by an externally applied dc voltage which is applied to a controlled circuit, such as a circuit including varactor diodes.
- U.S. Patent 4,694,260 discloses neither multiple microwave oscillators nor thermally coupling or frequency tracking abilities of such microwave oscillators.
- One object of this invention is to provide a thermally stable microwave oscillator bank which employs one stable frequency source and which generates a reference frequency, and also employs one or more thermally stabilized frequency discriminator, depending upon whether up- conversion of the output frequency is necessary.
- Another object of this invention is to provide a microwave oscillator bank which is capable of generating an array of millimeter-wave frequencies through direct modulation of the oscillators within the oscillator bank.
- Still another object of this invention is to provide a microwave oscillator bank and a corresponding frequency controller that maintains temperature stability within the oscillator bank, throughout a relatively long- term useful life of the components.
- the above and other objects of this invention are accomplished with a method for controlling frequency of a multi-channel transmitter in which a reference frequency is generated and emitted to a thermally stable frequency discriminator.
- a thermally stable frequency discriminator emits a dc voltage to a plurality of individual oscillators. Modulation is fed through each individual oscillator to an individual signal and all modulated individual signals are then combined into a multi ⁇ channel intermediate frequency.
- the multi-channel intermediate frequency is preferably amplified and then emitted as an output signal. However, the multi-channel intermediate frequency can also be directly fed as an output signal.
- the output signal is mixed with a control signal which is emitted at a control frequency from a local oscillator.
- the mixed signal is then preferably but not necessarily amplified.
- the control signal is mixed with a frequency reference signal generated from a stable frequency source to form a second mixed signal.
- the second mixed signal is emitted to another thermally stable frequency discriminator which emits a second dc voltage to the local oscillator.
- the control signal can be taken from a directional coupler which is exposed to the control signal.
- the second mixed signal can also be amplified.
- the modulated individual signals are preferably each at an intermediate frequency which is less than an output frequency of the output signal.
- the individual signals are preferably spaced by either one fixed frequency interval or an integer multiple of a fixed frequency interval.
- Frequency control is important in many different applications of microwave and millimeter-wave systems, such as wideband multi-channel communications systems and instrumentation, which require frequency tracking among the output spectral components.
- oscillator banks must generate highly stable frequencies, on both long-term and short-term bases. Such oscillator banks can operate in a carrier wave (CW) mode or can be modulated with various baseband signals.
- CW carrier wave
- the method and apparatus of this invention provides a highly stable oscillator bank which does not require phase-locked loops, such as in systems that operate at AM, FM, FSK, PAM, PPM and the like modulation techniques.
- phase-locking such as those that operate at BPSK, QPSK and the like modulation techniques
- the method and apparatus according to this invention provides effective control of the frequencies throughout elements in the oscillator bank, which thus reduces the required capture range of the phase-locked loops in the system.
- the method and apparatus according to this invention requires only one stable frequency reference and one or more thermally stable frequency discriminators, all of which preferably operate at a convenient intermediate frequency which is substantially lower than the millimeter-wave band of frequencies. If an oscillator bank system according to this invention operates at relatively low frequencies, such as 4-6 GHz, then exposing the output frequency to an up-conversion circuit is unnecessary and only one thermally stable frequency discriminator is necessary.
- Fig. 1 is a block diagram of a multi-channel millimeter-wave transmitter, according to one preferred embodiment of this invention
- Fig. 2 is a block diagram of a multi-channel millimeter-wave transmitter, according to another preferred embodiment of this invention.
- Fig. 4 is a block diagram of a frequency discriminator, according to one preferred embodiment of this invention.
- Fig. 1 shows a block diagram of a millimeter-wave transmitter, according to one preferred embodiment of this invention. Because of relatively higher losses in cables and waveguides at millimeter-wave frequencies, signals are preferably transmitted within a band of intermediate frequencies (IF) to a location near an antenna or another instrument, and are then up-converted to a millimeter-wave band for amplification and transmission.
- IF intermediate frequencies
- individual signals 15 are fed to modulator and combiner 20 which emits a multi-channel -modulated signal 21 preferably at an IF synthesized band, such as below approximately 10 GHz.
- a fixed frequency interval or a positive integer multiple of a fixed frequency interval is maintained between the individual modulated signals 21 emitted from modulator and combiner 20, so that no interference exists between the channels.
- the multi-channel IF signal is preferably sent to a transmitter, for example by way of a cable or waveguide.
- up-converter and filter 23 translates modulated signal 21 to an appropriate millimeter- wave band preferably for further amplification through power amplifier 24 and transmission through antenna 25.
- Frequency controller 22 is preferably used to control a frequency of a local oscillator, such as local oscillator 49 shown in Fig. 2, within up-converter and filter 23.
- frequency controller 19 is preferably used to control the frequency emitted from each individual oscillator within an oscillator bank.
- the oscillator positioned within up-converter and filter 23 can be subjected to temperature variations.
- the frequency of such oscillator can be monitored and controlled in order to regulate the emitted frequency range.
- an oscillator bank according to one preferred embodiment of this invention comprises oscillators 30-33. It is apparent that any number of a plurality of oscillators 30-33 can be employed, according to this invention.
- Oscillator 33 is intended to represent the n h oscillator within oscillator bank 29.
- individual oscillators 30-33 which operate at the IF band are thermally coupled with respect to each other. Such thermal coupling can be accomplished, for example, by positioning all individual oscillators 30-33 in an enclosed cabinet. Such enclosed cabinets are often used in an indoor environment and are well known by those skilled in the art of constructing enclosures for oscillator banks.
- reference oscillator 26 generates a reference frequency f r which is emitted to thermally stable frequency discriminator 27.
- Reference oscillator 26 is preferably positioned within the same environment, such as the physical cabinet enclosure, as individual oscillators 30-33. Also, reference oscillator 26 is preferably an electrical equivalent to any one of individual oscillators 30-33. In preferred embodiments according to this invention, reference oscillator 26 does not contribute to the IF signal.
- Reference oscillator 26 and oscillators 30-33 are preferably constructed with identical circuit design, layout and physical housings. Such similarity between reference oscillator 26 and each of oscillators 30-33 result in all of the oscillators being electrically equivalent with respect to each other.
- thermoelectric properties of the related semiconductor devices can be matched through well known measurement techniques apparent to those skilled in the art.
- any undesired offset in frequency between individual oscillators 30-33 can be adjusted by mechanical tuning.
- mechanical tuning can be accomplished by adjusting a metal plate above the dielectric resonator.
- Temperature coefficients of the resonant frequencies of oscillators with identical design are very close to each other.
- temperature compensation can be used to minimize any frequency drift.
- Frequency drift is detected at the output of reference oscillator 26.
- the frequency f r of reference oscillator 26 is preferably chosen so that as shown in Fig .
- any change in output frequency causes a dc output voltage from frequency discriminator 27.
- Such dc output voltage can be fed to individual oscillators 30-33 to cancel the shift in frequency between such oscillators 30-33.
- oscillators 30-33 are preferably temperature matched with respect to each other, the same dc output voltage can be used to correct the frequency drift between oscillators 30-33.
- thermally stable frequency discriminator 46 preferably generates a dc correction voltage which is proportional to the frequency drift in f L0 , and sends such dc correction voltage as an input to local oscillator 49.
- Fig. 3 shows another preferred embodiment according to this invention of an apparatus for controlling frequency of a multi-channel microwave transmitter.
- oscillator bank 29 operates in a relatively lower frequency range where losses due to cables and waveguides are relatively low.
- Fig. 3 shows a direct synthesis system which is capable of generating an array of microwave channels up to approximately 20 GHz.
- the system shown in Fig. 3 requires no up-conversion function and requires only one thermally stable frequency discriminator 27.
- oscillators should be phase-locked.
- the method and apparatus according to this invention can provide an effective means for preventing oscillators 30-33 from drifting out of a capture range of the phase-locked loops, as a result of temperature change and aging of the components.
- Each oscillator 30-33 can be controlled by both the frequency control voltages emitted from frequency discriminator 27, as well as by controlling an amplified mixer output of a phase-locked loop, which may derive a reference signal from a designated reference.
- phase control signal should have a much faster response time than the AFC signal emitted from frequency discriminator 27, so that the short-term stability of reference oscillator 26 as well as its phase can be easily regulated.
- the means for generating and emitting the referenced frequency to thermally stable frequency discriminator 27 comprises frequency oscillator 26 having an output electrically coupled to an input of frequency discriminator 27. It is apparent that such local oscillator can be any suitable oscillator or oscillating device known to those skilled in the art.
- oscillators 30-33 of oscillator bank 29 can be combined to receive the output signal from frequency discriminator 27, in any suitable hardware manner known to those skilled in the art.
- Summing device 35, mixers 41 and 45, and amplifiers 24, 37 and 54 can also be of any conventional hardware components known to those skilled in the art.
Abstract
Description
Claims
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NZ306032A NZ306032A (en) | 1995-02-28 | 1996-02-28 | Frequency control of multichannel transmitter without phase lock loop |
APAP/P/1997/001095A AP809A (en) | 1995-02-28 | 1996-02-28 | Method and apparatus for controlling frequency of a multi-channel transmitter. |
AT96911237T ATE227908T1 (en) | 1995-02-28 | 1996-02-28 | METHOD AND ARRANGEMENT FOR CONTROLLING THE FREQUENCY OF A MULTI-CHANNEL TRANSMITTER |
UA97094789A UA42829C2 (en) | 1995-02-28 | 1996-02-28 | Method for multichannel transmitter frequency control, and frequency controller |
AU54184/96A AU706897B2 (en) | 1995-02-28 | 1996-02-28 | Method and apparatus for controlling frequency of a multi-channel transmitter |
EP96911237A EP0872051B1 (en) | 1995-02-28 | 1996-02-28 | Method and apparatus for controlling frequency of a multi-channel transmitter |
DE69624838T DE69624838T2 (en) | 1995-02-28 | 1996-02-28 | METHOD AND ARRANGEMENT FOR REGULATING THE FREQUENCY OF A MULTI-CHANNEL TRANSMITTER |
BG101928A BG63446B1 (en) | 1995-02-28 | 1997-09-29 | Method and device for multichannel transmitter frequency control |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/396,137 US5768693A (en) | 1995-02-28 | 1995-02-28 | Method and apparatus for controlling frequency of a multi-channel transmitter |
US08/396,137 | 1995-02-28 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO1996027948A2 true WO1996027948A2 (en) | 1996-09-12 |
WO1996027948A3 WO1996027948A3 (en) | 1996-12-05 |
Family
ID=23566004
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1996/002847 WO1996027948A2 (en) | 1995-02-28 | 1996-02-28 | Method and apparatus for controlling frequency of a multi-channel transmitter |
Country Status (11)
Country | Link |
---|---|
US (2) | US5768693A (en) |
EP (1) | EP0872051B1 (en) |
AP (1) | AP809A (en) |
AT (1) | ATE227908T1 (en) |
AU (1) | AU706897B2 (en) |
BG (1) | BG63446B1 (en) |
DE (1) | DE69624838T2 (en) |
NZ (1) | NZ306032A (en) |
RU (1) | RU2183050C2 (en) |
UA (1) | UA42829C2 (en) |
WO (1) | WO1996027948A2 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5768693A (en) * | 1995-02-28 | 1998-06-16 | Telecommunications Equipment Corporation | Method and apparatus for controlling frequency of a multi-channel transmitter |
JPH11340738A (en) * | 1998-05-22 | 1999-12-10 | Murata Mfg Co Ltd | Oscillator and communication equipment |
IT1305710B1 (en) * | 1998-12-11 | 2001-05-15 | Itelco S P A | METHOD FOR THE TRANSMISSION OF MORE BROADCAST TYPE SIGNALS |
US6677862B1 (en) | 1999-05-17 | 2004-01-13 | Schlumbergersema Inc. | Transmitter tolerant to crystal variations |
US6477558B1 (en) | 1999-05-17 | 2002-11-05 | Schlumberger Resource Management Systems, Inc. | System for performing load management |
US6163276A (en) * | 1999-05-17 | 2000-12-19 | Cellnet Data Systems, Inc. | System for remote data collection |
US6452986B1 (en) | 1999-05-17 | 2002-09-17 | Cellnet Data Systems, Inc. | Detector tolerant of frequency misalignment |
US6181258B1 (en) | 1999-05-17 | 2001-01-30 | Cellnet Data Systems, Inc. | Receiver capable of parallel demodulation of messages |
US6714089B2 (en) * | 2002-05-29 | 2004-03-30 | Xytrans, Inc. | High frequency signal source and method of generating same using dielectric resonator oscillator (DRO) circuit |
JP4843104B2 (en) * | 2007-08-10 | 2011-12-21 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Multiplex transmission equipment with reduced coupling |
JP2010008273A (en) * | 2008-06-27 | 2010-01-14 | Maspro Denkoh Corp | Millimeter wave imaging apparatus |
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US3593182A (en) * | 1969-04-16 | 1971-07-13 | Motorola Inc | Afc system for microwave energy sources |
US3867706A (en) * | 1973-11-08 | 1975-02-18 | Frequency Sources Inc | Frequency control and stabilization means and frequency discriminator |
US4780691A (en) * | 1987-08-03 | 1988-10-25 | Ford Aerospace & Communications Corporation | Dielectric resonator frequency discriminator for stabilizing oscillator frequency |
EP0307595A1 (en) * | 1987-09-11 | 1989-03-22 | Siemens Aktiengesellschaft | Circuit arrangement for generating two very near frequencies |
US4910793A (en) * | 1986-12-08 | 1990-03-20 | Alsthom | Two-way transmission system for ground/mobile station communications |
EP0536835A1 (en) * | 1991-10-09 | 1993-04-14 | Philips Electronics Uk Limited | Microwave oscillators and transmitters with frequency stabilization |
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US3614640A (en) * | 1970-01-27 | 1971-10-19 | Us Navy | Frequency discriminator using no inductive components |
US3686574A (en) * | 1970-08-19 | 1972-08-22 | Hallicrafters Co | Self-correcting afc system |
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US5768693A (en) * | 1995-02-28 | 1998-06-16 | Telecommunications Equipment Corporation | Method and apparatus for controlling frequency of a multi-channel transmitter |
-
1995
- 1995-02-28 US US08/396,137 patent/US5768693A/en not_active Expired - Fee Related
-
1996
- 1996-02-28 EP EP96911237A patent/EP0872051B1/en not_active Expired - Lifetime
- 1996-02-28 AP APAP/P/1997/001095A patent/AP809A/en active
- 1996-02-28 NZ NZ306032A patent/NZ306032A/en unknown
- 1996-02-28 AU AU54184/96A patent/AU706897B2/en not_active Ceased
- 1996-02-28 UA UA97094789A patent/UA42829C2/en unknown
- 1996-02-28 WO PCT/US1996/002847 patent/WO1996027948A2/en active IP Right Grant
- 1996-02-28 AT AT96911237T patent/ATE227908T1/en not_active IP Right Cessation
- 1996-02-28 DE DE69624838T patent/DE69624838T2/en not_active Expired - Fee Related
- 1996-02-28 RU RU97116518/09A patent/RU2183050C2/en active
-
1997
- 1997-09-29 BG BG101928A patent/BG63446B1/en unknown
-
1998
- 1998-06-16 US US09/097,619 patent/US6081696A/en not_active Expired - Fee Related
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Publication number | Priority date | Publication date | Assignee | Title |
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US3593182A (en) * | 1969-04-16 | 1971-07-13 | Motorola Inc | Afc system for microwave energy sources |
US3867706A (en) * | 1973-11-08 | 1975-02-18 | Frequency Sources Inc | Frequency control and stabilization means and frequency discriminator |
US4910793A (en) * | 1986-12-08 | 1990-03-20 | Alsthom | Two-way transmission system for ground/mobile station communications |
US4780691A (en) * | 1987-08-03 | 1988-10-25 | Ford Aerospace & Communications Corporation | Dielectric resonator frequency discriminator for stabilizing oscillator frequency |
EP0307595A1 (en) * | 1987-09-11 | 1989-03-22 | Siemens Aktiengesellschaft | Circuit arrangement for generating two very near frequencies |
EP0536835A1 (en) * | 1991-10-09 | 1993-04-14 | Philips Electronics Uk Limited | Microwave oscillators and transmitters with frequency stabilization |
Also Published As
Publication number | Publication date |
---|---|
EP0872051A2 (en) | 1998-10-21 |
AU706897B2 (en) | 1999-07-01 |
BG101928A (en) | 1998-12-30 |
NZ306032A (en) | 1999-05-28 |
AP9701095A0 (en) | 1997-10-31 |
AU5418496A (en) | 1996-09-23 |
US6081696A (en) | 2000-06-27 |
EP0872051B1 (en) | 2002-11-13 |
AP809A (en) | 2000-02-04 |
UA42829C2 (en) | 2001-11-15 |
US5768693A (en) | 1998-06-16 |
ATE227908T1 (en) | 2002-11-15 |
DE69624838D1 (en) | 2002-12-19 |
RU2183050C2 (en) | 2002-05-27 |
WO1996027948A3 (en) | 1996-12-05 |
BG63446B1 (en) | 2002-01-31 |
DE69624838T2 (en) | 2003-09-18 |
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