WO2002047250A2 - Quadrature modulator - Google Patents

Quadrature modulator Download PDF

Info

Publication number
WO2002047250A2
WO2002047250A2 PCT/GB2001/005179 GB0105179W WO0247250A2 WO 2002047250 A2 WO2002047250 A2 WO 2002047250A2 GB 0105179 W GB0105179 W GB 0105179W WO 0247250 A2 WO0247250 A2 WO 0247250A2
Authority
WO
WIPO (PCT)
Prior art keywords
vector
signal
component
product
value
Prior art date
Application number
PCT/GB2001/005179
Other languages
French (fr)
Other versions
WO2002047250A3 (en
Inventor
Mel Long
Original Assignee
Ubinetics Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ubinetics Limited filed Critical Ubinetics Limited
Priority to AU2002223880A priority Critical patent/AU2002223880A1/en
Publication of WO2002047250A2 publication Critical patent/WO2002047250A2/en
Publication of WO2002047250A3 publication Critical patent/WO2002047250A3/en

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/02—Details

Definitions

  • the invention relates to signal processing and, in particular, to the modulation of information onto a signal destined for transmission.
  • a known type of transmitter transmits a signal having two components which together define a vector.
  • the information conveyed by the transmitted signal is represented by a change in the angle of the vector about a notional origin.
  • a clockwise rotation of the vector can indicate the transmission of a bit having value logical one and an anti-clockwise rotation of the vector indicates the transmission of a bit having value logical zero (if the angle of the vector does not change from one instant to the next, then no information has been transmitted during that time).
  • the data to be transmitted dictates the rotation of the vector.
  • the data to be transmitted is used to index a lookup table which outputs the corresponding values for the components forming the vector so as to impart the necessary rotation to the vector in accordance with the data encoding scheme.
  • One object of the invention is to provide improved signal modulation.
  • the invention provides a method of modulating a signal representing a rotating vector comprising changing the signal by rotating the vector from its present position to a new position by calculating the new position from the old position and the rotation of the vector.
  • the invention provides apparatus for modulating a signal representing a rotating vector comprising means for changing the signal by rotating the vector from its present position to a new position by calculating the new position from the old position and the rotation of the vector.
  • the invention provides for the calculation of changes in the vector without recourse to, and hence avoiding the disadvantages of, a lookup table (e.g. the consumption of relatively large amounts of memory).
  • the vector of the signal can be represented by two components, and a change in the vector can be calculated by using the present component values together with the desired angular rotation, ⁇ , of the vector to calculate the new component values for the new vector position.
  • the new value of the first component can be calculated as the sum of the product of its present value and sine ⁇ and the product of the present value of the second component and cosine ⁇ .
  • the new value of the second component can be calculated as the product of its present value and sine ⁇ subtracted from the product of the present value of the first component and cosine ⁇ .
  • the invention is used to modulate information onto a signal destined for transmission.
  • the invention also extends to a program for causing data processing apparatus to modulate a signal in accordance with the methods described above.
  • Figure 1 is a signal space diagram illustrating the modulation scheme of a transmitted signal
  • Figure 2 is a block diagram of a transmitter.
  • the signal space diagram shows a transmitted signal represented by a vector 10.
  • the vector 10 is shown relative to an in-phase (I) axis and quadrature (Q) axis.
  • the vector 10 can be represented by a component 12 parallel to the I axis and a component 14 parallel to the Q axis.
  • the transmitted signal comprises these I and Q components, and their magnitudes determine the location of the tip of vector 10 in the signal space diagram.
  • Data is modulated onto the transmitted signal by rotating the vector 10 about the I, Q origin. This means that the tip of vector 10 traces out a circular path 16 centred on the origin. If no data is to be transmitted, then the vector 10 does not rotate. If a bit of value logical 0 is to be transmitted, then the vector rotates anti-clockwise by a fixed increment ⁇ from its current position and the tip of vector 10 moves from point 18 to point 20. If a logical one is to be transmitted, then the tip of vector 10 rotates clockwise by the same amount, ⁇ , to point 22.
  • the transmitter of Figure 2 uses the data encoding scheme described with reference to Figure 1.
  • Processor 24 produces the data for transmission and supplies it to modulator 24 which modulates the data onto a signal comprised of I and Q components which is then transmitted from antenna 26.
  • the modulator 24 adjusts the magnitudes of the I and Q components of the transmitted signal in accordance with the data to be transmitted.
  • the modulator 24 calculates the values I 2 and Q 2 from Ii and Qi using the following equations:
  • ⁇ is the rotation of the vector (a positive value indicating clockwise rotation and a negative value indicating anti-clockwise rotation).
  • the system Since the system calculates new values for the I and Q components from the current values of the I and Q components the system does not need to rely on a lookup table and avoids the associated memory consumption.

Landscapes

  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

A transmitted signal comprises two components which define a vector. Modulation of the signal entails rotating the vector. The new values of the components needed to represent a change in the rotation of the vector are calculated from the old component values and the desired rotation angle.

Description

SIGNAL PROCESSING
The invention relates to signal processing and, in particular, to the modulation of information onto a signal destined for transmission.
A known type of transmitter transmits a signal having two components which together define a vector. The information conveyed by the transmitted signal is represented by a change in the angle of the vector about a notional origin. For example, a clockwise rotation of the vector can indicate the transmission of a bit having value logical one and an anti-clockwise rotation of the vector indicates the transmission of a bit having value logical zero (if the angle of the vector does not change from one instant to the next, then no information has been transmitted during that time). Thus, the data to be transmitted dictates the rotation of the vector.
Ordinarily, in a transmitter of the kind described above, the data to be transmitted is used to index a lookup table which outputs the corresponding values for the components forming the vector so as to impart the necessary rotation to the vector in accordance with the data encoding scheme.
One object of the invention is to provide improved signal modulation.
According to one aspect, the invention provides a method of modulating a signal representing a rotating vector comprising changing the signal by rotating the vector from its present position to a new position by calculating the new position from the old position and the rotation of the vector.
According to another aspect, the invention provides apparatus for modulating a signal representing a rotating vector comprising means for changing the signal by rotating the vector from its present position to a new position by calculating the new position from the old position and the rotation of the vector. Thus, the invention provides for the calculation of changes in the vector without recourse to, and hence avoiding the disadvantages of, a lookup table (e.g. the consumption of relatively large amounts of memory).
The vector of the signal can be represented by two components, and a change in the vector can be calculated by using the present component values together with the desired angular rotation, θ, of the vector to calculate the new component values for the new vector position. The new value of the first component can be calculated as the sum of the product of its present value and sine θ and the product of the present value of the second component and cosine θ. The new value of the second component can be calculated as the product of its present value and sine θ subtracted from the product of the present value of the first component and cosine θ.
In a preferred embodiment, the invention is used to modulate information onto a signal destined for transmission.
The invention also extends to a program for causing data processing apparatus to modulate a signal in accordance with the methods described above.
By way of example only, an embodiment of the invention will now be described with reference to the accompanying figures, in which:
Figure 1 is a signal space diagram illustrating the modulation scheme of a transmitted signal; and
Figure 2 is a block diagram of a transmitter.
Referring now to Figure 1, the signal space diagram shows a transmitted signal represented by a vector 10. The vector 10 is shown relative to an in-phase (I) axis and quadrature (Q) axis. The vector 10 can be represented by a component 12 parallel to the I axis and a component 14 parallel to the Q axis. The transmitted signal comprises these I and Q components, and their magnitudes determine the location of the tip of vector 10 in the signal space diagram.
Data is modulated onto the transmitted signal by rotating the vector 10 about the I, Q origin. This means that the tip of vector 10 traces out a circular path 16 centred on the origin. If no data is to be transmitted, then the vector 10 does not rotate. If a bit of value logical 0 is to be transmitted, then the vector rotates anti-clockwise by a fixed increment θ from its current position and the tip of vector 10 moves from point 18 to point 20. If a logical one is to be transmitted, then the tip of vector 10 rotates clockwise by the same amount, θ, to point 22.
The transmitter of Figure 2 uses the data encoding scheme described with reference to Figure 1. Processor 24 produces the data for transmission and supplies it to modulator 24 which modulates the data onto a signal comprised of I and Q components which is then transmitted from antenna 26. The modulator 24 adjusts the magnitudes of the I and Q components of the transmitted signal in accordance with the data to be transmitted. The I and Q components of the transmitted signal represent a vector, N=I+Q. Where the present state of the vector is Nι=Iι+Qι the vector is rotated during data modulation to N2=I2+Q2. The modulator 24 calculates the values I2 and Q2 from Ii and Qi using the following equations:
Figure imgf000005_0001
Q2=IιCθsθ-Qιsinθ
θ is the rotation of the vector (a positive value indicating clockwise rotation and a negative value indicating anti-clockwise rotation).
Since the system calculates new values for the I and Q components from the current values of the I and Q components the system does not need to rely on a lookup table and avoids the associated memory consumption.

Claims

Claims
1. A method of modulating a signal representing a rotating vector comprising changing the signal by rotating the vector from its present position to a new position by calculating the new position from the old position and the rotation of the vector.
2. A method according to claim 1, wherein the signal comprises two components together representing the vector and the component values of the new position are calculated from the present component values using the angular rotation, θ, of the vector.
3. A method according to claim 2, wherein the new value of the first component is calculated as the sum of the product of its present value and sine θ and the product of the present value of the second component and cosine θ.
4. A method according to claim 2 or claim 3, wherein the new value of the second component is calculated as the product of its present value and sine 0 subtracted from the product of the present value of the first component and cosine θ.
5. A method according to any preceding claim, wherein the rotation of the vector is determined by data which is to be conveyed by the signal.
6. A method of transmitting information by modulating the information onto a signal using the method of any preceding claim.
7. Apparatus for modulating a signal representing a rotating vector comprising means for changing the signal by rotating the vector from its present position to a new position by calculating the new position from the old position and the rotation of the vector.
8. Apparatus according to claim 7, wherein the signal comprises two components together representing the vector, and the means for changing the signal calculates the component values of the new position from the present component values using the angular rotation, θ, of the vector.
9. Apparatus according to claim 8, wherein the means for changing the signal calculates the new value of the first component as the sum of the product of its present value and sine θ and the product of the present value of the second component and cosine θ.
10. Apparatus according to claim 8, wherein the means for changing the signal calculates the new value of the second component as the product of its present value and sine θ subtracted from the product of the present value of the first component and cosine θ.
11. Apparatus according to any one of claims 7 to 10, wherein the rotation of the vector is determined by data which is to be conveyed by the signal.
12. Apparatus for transmitting information by modulating the information onto a signal using the modulating apparatus of any one of claims 7 to 11.
13. A program for causing data processing apparatus to perform the method of any one of claims 1 to 6.
14. A method of modulating a signal, substantially as hereinbefore described with reference to the accompanying figures.
15. A method of transmitting a signal, substantially as hereinbefore described with reference to the accompanying figures.
16. Apparatus for modulating a signal, substantially as hereinbefore described with reference to the accompanying figures.
17. Apparatus for transmitting a signal, substantially as hereinbefore described with reference to the accompanying figures.
PCT/GB2001/005179 2000-12-05 2001-11-23 Quadrature modulator WO2002047250A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002223880A AU2002223880A1 (en) 2000-12-05 2001-11-23 Quadrature modulator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0029615A GB2369942A (en) 2000-12-05 2000-12-05 Phase modulation
GB0029615.2 2000-12-05

Publications (2)

Publication Number Publication Date
WO2002047250A2 true WO2002047250A2 (en) 2002-06-13
WO2002047250A3 WO2002047250A3 (en) 2003-05-22

Family

ID=9904461

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2001/005179 WO2002047250A2 (en) 2000-12-05 2001-11-23 Quadrature modulator

Country Status (3)

Country Link
AU (1) AU2002223880A1 (en)
GB (1) GB2369942A (en)
WO (1) WO2002047250A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006015537A1 (en) * 2004-08-08 2006-02-16 Huawei Technologies Co., Ltd. System and method for realizing the security management in 3g mobile communication network

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0545546A2 (en) * 1991-11-30 1993-06-09 Nokia Mobile Phones (U.K.) Limited Digital GMSK transceiver
EP0632369A1 (en) * 1993-06-29 1995-01-04 Stichting voor de Technische Wetenschappen CORDIC algorithms and architectures
EP0809195A2 (en) * 1996-05-22 1997-11-26 HE HOLDINGS, INC. dba HUGHES ELECTRONICS Analog waveform communications reduced instruction set processor
EP0982905A1 (en) * 1998-08-28 2000-03-01 Sony International (Europe) GmbH Universal PSK modulation apparatus and method
WO2000065799A1 (en) * 1999-04-23 2000-11-02 Nokia Networks Oy Qam modulator

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9002786D0 (en) * 1990-02-08 1990-04-04 Marconi Co Ltd Phase shifting circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0545546A2 (en) * 1991-11-30 1993-06-09 Nokia Mobile Phones (U.K.) Limited Digital GMSK transceiver
EP0632369A1 (en) * 1993-06-29 1995-01-04 Stichting voor de Technische Wetenschappen CORDIC algorithms and architectures
EP0809195A2 (en) * 1996-05-22 1997-11-26 HE HOLDINGS, INC. dba HUGHES ELECTRONICS Analog waveform communications reduced instruction set processor
EP0982905A1 (en) * 1998-08-28 2000-03-01 Sony International (Europe) GmbH Universal PSK modulation apparatus and method
WO2000065799A1 (en) * 1999-04-23 2000-11-02 Nokia Networks Oy Qam modulator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006015537A1 (en) * 2004-08-08 2006-02-16 Huawei Technologies Co., Ltd. System and method for realizing the security management in 3g mobile communication network

Also Published As

Publication number Publication date
AU2002223880A1 (en) 2002-06-18
GB0029615D0 (en) 2001-01-17
WO2002047250A3 (en) 2003-05-22
GB2369942A (en) 2002-06-12

Similar Documents

Publication Publication Date Title
JP2001505016A (en) Digital quadrature modulation and demodulation method, and digital quadrature modulator and demodulator
US5550506A (en) DQPSK demodulator capable of improving a symbol error rate without decreasing a transmission rate
CN105637826A (en) Likelihood generation circuit and likelihood generation method
EP0220005A2 (en) Phase rotation of signals
US5504453A (en) Method and device for estimating phase error
WO2002047250A2 (en) Quadrature modulator
JP3185867B2 (en) Error detection method and device, signal demodulation method and device
KR0143421B1 (en) Wipe pattern generators
EP4109833A1 (en) Signal pre-compensation method and apparatus
EP0987863A1 (en) Soft decision method and apparatus for 8PSK demodulation
JPH07154303A (en) Data receiver
CN101199178B (en) Communication device, communication system, and modulating method
JP5261142B2 (en) Optical communication apparatus and signal point arrangement determination method
US5767739A (en) Digital demodulator for quadrature amplitude and phase modulated signals
EP0982905B1 (en) Universal PSK modulation apparatus and method
JPS63248257A (en) Digital modulating/demodulating system
US20040096023A1 (en) Reduced phase error derotator system and method
US20080107222A1 (en) System and method for signal phase correction
US5796784A (en) Method and apparatus for modifying amplitude of at least one symbol
CN102761341B (en) Method and device for decoding coset
US6100755A (en) Phase decision circuit
JP4120937B2 (en) Phase rotation method and phase rotation device
US20070030915A1 (en) Receiver Block Providing Signal Quality Information in a Communication System with Signal Constellation not Having multiple Symbols in Same Angle
CN110771110B (en) Likelihood generation device
RU2159016C2 (en) Method and device for phase angle detection

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase in:

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP