Pulse or digital communications – Transceivers
Patent
1995-07-18
1998-08-11
Tse, Young T.
Pulse or digital communications
Transceivers
375226, 375227, 375296, 375308, 455126, H04B 701, H04B 138
Patent
active
057938008
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method for minimizing the phase error of a transmitter of a transceiver unit. The invention also relates to a transceiver unit for transmitting and receiving signals, this unit comprising a transmitter, a receiver and antenna means for establishing a radio contact with active radio units currently located in the coverage area of the transceiver unit.
A transceiver unit refers in this context to a unit which comprises both a radio receiver and a radio transmitter. The present invention relates particularly to adjusting the phase error of the transmitter of a transmitter unit, this adjustment being carried out, as known, unit-specifically in connection with the manufacture of the unit. The practice has however shown that a phase error due to the component tolerances of a transmitter will not remain constant but changes unit-specifically as the transmitter ages, whereby it is necessary to readjust the transmitter separately for each unit. Since this operation requires the presence of maintenance staff, it is rather expensive in addition to taking up a lot of time, during which time the transceiver unit cannot be used for normal traffic operation.
SUMMARY OF THE INVENTION
The object of the invention is to solve the above-mentioned problem, and to provide a method by means of which the adjustment of the phase error of a transceiver unit can be performed in a significantly simpler and quicker manner than before. These objects are achieved with the method of the invention, characterized in that a predetermined test signal is applied via a delay means to the input of the transmitter section of the transceiver unit; the output signal of the transmitter section is converted to the receive frequency of the receiver; the receive-frequency signal is applied to the receiver of the transceiver unit; the output signal of the receiver is compared to the predetermined test signal; and the delay means is adjusted on the basis of the result of the comparison in such a manner that the phase error of the transmitter is minimized.
The invention also relates to a transceiver unit in which the method of the invention can be applied. The transceiver unit of the invention is characterized in that the unit comprises a memory means, in which test data is stored; a delay means, which is connected to the input of the transmitter and via which data is applied to the transmitter; a mixing means for converting a test signal, which is applied by the transmitter and generated from the test data stored in the memory means, from a transmit frequency to a receive frequency, the output of the mixing means being connected so as to apply the receive-frequency test signal to the input of the receiver; and a control means for applying the test data stored in the memory means via the delay means to the transmitter of the unit, for comparing the output signal of the receiver to the test data stored in the memory means, and for adjusting the delay means on the basis of the abovementioned comparison so that the difference between the output signal and the stored test data is minimized.
The invention is based on the idea that the transceiver unit is provided with means by which the phase error of the transmitter can be automatically adjusted without this requiring any special maintenance operations. The most significant advantages of the method and the transceiver unit of the invention are thus that it is not necessary to separately adjust the phase error of the transceiver unit at the manufacturing stage, which facilitates the process of manufacture of the unit, and that the ageing of the unit does not affect the phase error, because the phase error can be continuously adjusted by means of the automatic adjusting means located in the transceiver unit.
In a preferred embodiment of the transceiver unit of the invention, the unit comprises means for transmitting two signals by using quadrature modulation. The minimization of the phase error of the transmitter can thus be carried out by vary
REFERENCES:
patent: 4291277 (1981-09-01), Davis et al.
patent: 4462001 (1984-07-01), Girard
patent: 4700151 (1987-10-01), Nagata
patent: 5066922 (1991-11-01), Leitch
patent: 5066923 (1991-11-01), Gailus et al.
patent: 5212814 (1993-05-01), Iwane
patent: 5351016 (1994-09-01), Dent
patent: 5381108 (1995-01-01), Whitmarsh et al.
patent: 5396196 (1995-03-01), Blodgett
patent: 5404378 (1995-04-01), Kimura
patent: 5469105 (1995-11-01), Sparks
patent: 5483681 (1996-01-01), Bergsten et al.
patent: 5507017 (1996-04-01), Whitmarsh et al.
patent: 5574994 (1996-11-01), Huang et al.
Jylha Raimo
Kahkola Mika
Neitiniemi Jukka-Pekka
Nokia Telecommunications Oy
Tse Young T.
LandOfFree
Method and apparatus for minimizing phase error in a transmitter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for minimizing phase error in a transmitter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for minimizing phase error in a transmitter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-397537