O
`
`UIllted States Patent [19]
`Vanhanen et al.
`
`USOO5276917A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,276,917
`Jan. 4, 1994
`
`[54] TRANSMITTER SWITCH-ON IN A
`DUAL'MODE MOBILE PROM‘:
`[75] Inventors: Petterl Vanhanen, Jaali; Markku
`Myrslwg, 0111"; Ar?" SePPane“!
`Oulunsalo, all of Finland
`_
`_
`_
`[73] Ass1gnee: Nolua Mobile Phones Ltd., Salo,
`Fmland
`[21] App]. No.: 781,998
`[22] Filed:
`oct- 22’ 1991
`[51] Int. c1.5 ...................... .. HOlQ 11/12; H04B 1/04
`[52] US. Cl. ...................................... .. 455/39; 455/95;
`455/119; 455/127; 330/51; 330/310; 379/59
`[58] Field of Search ................ .. 455/ 13.4, 89, 95, 126,
`455/ 127, 115, 116, 119; 330/51, 149, 310;
`379/59
`
`[56]
`
`Cit d
`R f
`e erences
`e
`U5‘ PATENT DOCUMENTS
`3,962,553 6/1976 Linder et a1.
`4,288,753 9/1981 Babano . . . . . . . 1 . . . . .
`
`455/89
`. . . .. 330/51
`
`Iii-Pk?!" 9‘ al
`4:37:33;
`jjjj 330,51
`210591105 7/1991 ‘1112;115:3191:
`330/51
`5,060,294 10/1991 Schwent et al
`455/89
`5,109,541 4/1992 Park ................ ..
`5,150,075 9/1992 Hietala et al. ..................... .. 455/ 126
`
`5,159,283 10/1992 Jensen ............................... .. 455/ 126
`FOREIGN PATENT DOCUMENTS
`0407135 V1991 European PM on _
`0416613 3/1991 European Pat. Off. .
`
`Primary Examiner-Reinhard J. Eisenzopf
`Assistant Examiner_Timothy H Keough
`Attorney, Agent, or Firm-Darby & Darby
`[57]
`ABSTRACI‘
`A method for providing a positive transmitter power
`switch-0n in '8 dual-mode mobile Phone is disclosed
`According to the invention the transmitter is switched
`on in two or more phases, controlled by the mobile
`phone microprocessor program. Preferably the power
`ampli?er sections are switched on in a sequence, so that
`the output power ampli?er sections (3 and 4) are ?rst
`switched on by enabling the transmit enable signal
`(TXE). Then the input power ampli?er sections (1 and
`2) are switched on by enabling ramp-up signal (RAMP
`UP) Transmission is thereafter enabled by the transmit
`power control signal (TXC) being switched on, the
`
`ampli?ers then output the ampli?ed radio frequency
`input si1gnal)€RFIN) to the duplex circuit (10) transmit
`lemma (T )
`
`6 Claims, 1 Drawing Sheet
`
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`CONTROL
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`31
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`4
`
`TCL EXHIBIT 1083
`Page 1 of 4
`
`

`
`TCL EXHIBIT 1083
`Page 2 of 4
`
`

`
`1
`
`5,276,917
`
`TRANSMITTER SWITCH-ON IN A DUAL-MODE
`MOBILE PHONE
`
`5
`
`BACKGROUND OF THE INVENTION
`This invention relates to a method for providing a
`positive transmitter power switch-on in a dual-mode
`mobile radiotelephone having a programmable logic in
`the digital mode controlling the switching-on of two or
`more transmitting power ampli?er sections.
`In digital mobile radiotelephones planned to operate
`according to North American dual-mode standard it is
`required that the transmitter must be switched off dur
`ing certain speci?ed intervals when the mobile phone
`15
`operates in the digital mode. The transmitter is switched
`on for transmission during transmission intervals. A
`simple on/off switching of the transmitter produces
`some negative effects, e. g. a very broad frequency spec
`trum of the transmitter in the initial transmission phase.
`
`30
`
`SUMMARY OF THE INVENTION
`It is an object of the present invention to provide a
`method of switching the transmitter that is effectively
`eliminates the drawbacks of simple transmitter on/off
`switching in digital mobile radio telephones. It is further
`an object of this invention to provide a transmitter ar
`rangement operating according to the inventive
`method.
`According to the inventive method the transmitter is
`switched on in two or more phases that ensure a stable
`operation of the transmitter. The method of the pre
`ferred embodiment consists of the steps of sequentially
`switching on the power ampli?er sections; and thereaf
`ter switching on the transmit power control signal. In
`35
`another embodiment the sequential ampli?er switch on
`consists of two steps: switching on the output power
`ampli?er sections by enabling the transmit enable sig
`nal; and thereafter switching on the input power ampli
`?er sections by enabling the ramp-up signal.
`Still another embodiment comprises the steps of ?rst
`40
`switching on the output power ampli?er sections by
`enabling the transmit enable signal; and thereafter
`switching on the input power ampli?er sections by
`enabling the ramp-up signal, and switching on the trans
`mit power control signal.
`The inventive dual-mode mobile radiotelephone op
`erates in accordance with the method as described.
`
`45
`
`2
`nected to the transmitter section input RFIN at the
`voltage controlled ampli?er/attenuator 5, the output of
`which is connected to a series of controllable linear
`power ampli?ers 1, 2, 3 and 4. The output of the last
`ampli?er 4 is connected to the TX terminal of the du
`plex circuit 10.
`In this example the ampli?er stages 1 and 2 are simul
`taneously controlled on/off by a ramp-up control cir
`cuit 6 controlled by the signal at the RAMP-UP input.
`The control circuit 6 consists of a series transistor,
`which connects on/off the regulated bias to the ampli?
`ers 1 and 2. The power ampli?er stages 3 and 4 are
`controlled on/off by respective bias control circuits 8
`and 9. These bias control circuits 8 and 9 are controlled
`by the MODE input. The control circuits 6, 8 and 9
`receive a regulated bias signal through the regulator
`circuit 7 controlled by the signal at the TXE input. The
`voltage regulator 7 and the bias control circuits 8 and 9,
`as well as the power ampli?ers 3 and 4 are connected to
`the main battery voltage +V, e.g. +5 V.
`The transmitter section output power level is con
`trolled in a closed loop through the power control
`block 13, consisting essentially of a voltage controlled
`circuit including a comparator and an ampli?er. The
`power output to the duplex circuit 10 is measured with
`a sensor device 12, essentially a directional coupler,
`which generates a signal output at terminal TXI to the
`controlling logic and connected to the power control
`block 13. The power control block 13 receives a con
`trolling signal through the TXC input and compares
`this TXC signal with the measurement signal from cir
`cuit 12, whereby the difference is ampli?ed and con
`nected as a negative feedback signal to the voltage con
`trolled ampli?er/attenuator 5.
`The terminals TXE, RAMP-UP, MODE, TXC and
`TXI are connected to the controlling logic (not shown
`in the ?gure) of the dual-mode mobile phone. The logic
`is realized with a microprocessor or a suitable controller
`known in the industry. The logic also includes suitable
`programs that control the operation of the mobile
`phone according to the appropriate standards and to the
`wishes of the user.
`According to the requirements this transmitter ar
`rangement has to operate in two modes, controlled by
`the MODE signal. In the analog mode (AMPS) there is
`required a continuous full or pre-de?ned power of the
`transmitter. In the digital mode the required power or
`ef?ciency may be lower, due to a pulsed operating
`principle. According to the appropriate standards the
`digital mode consists of a pulsed operation, i.e. the
`transmitter is sequentially connected on during a period
`6,7 ms and off during a period 2X6,7 ms. Thus in the
`digital mode the transmitter is on or transmitting only
`one third of the time and off or not transmitting two
`thirds of the time. The transmitter must not connect any
`spurious signals or noise through ampli?ers l-4 to the
`antenna during the off period (according to the require
`ments the antenna signal must be less than —60 dBm
`during the off period).
`The straightforward solution to the pulsed operation
`would be to switch the transmitter totally on and off, in
`response to a controlling signal, in this case e.g. the
`signals TXE (enable), TXC and MODE being con
`nected on/off at the same moment controlled by the
`mobile phone logic or the microprocessor. This would,
`however, produce a very broad frequency spectrum at
`the antenna output at the beginning of each transmission
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The invention is further described by way of example
`with reference to the accompanying drawing, in which
`the only ?gure is a block diagram showing the main
`parts of the digital transmitter in a dual-mode mobile
`radio telephone.
`DESCRIPTION OF ILLUSTRATIVE
`EMBODIMENTS
`In the ?gure the transmitter in a dual-mode mobile
`radio telephone operating according to the North
`American dual-mode standard is connected to transmit~
`60
`ter input TX of the duplex circuit 10, the output of
`which is connected to the antenna 11. The receiving
`parts (not shown) of the mobile phone are connected to
`the RX interface of the duplex circuit 10. The analog
`parts of the mobile phone operating according to the
`AMPS standard are not shown in the ?gure.
`The radio frequency signal to be transmitted —
`' which in this case is of the order 850 MHz — is con
`
`55
`
`65
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`TCL EXHIBIT 1083
`Page 3 of 4
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`

`
`5
`
`20
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`25
`
`30
`
`35
`
`4
`
`5,276,917
`3
`period, before the transmitter is stabilized. This instable
`We claim:
`operation occurs due to the impedance level changes at
`1. A method for providing a positive transmitter
`each ampli?er section, when the power is switched on.
`power switch-on of a transmitter in a dual-mode mobile
`radiotelephone having programmable logic in the digi
`This instability period would also have a negative effect
`on the synthesizer circuit, degrading the frequency
`tal mode for controlling switching-on of at least two
`stability.
`transmitting power ampli?er sections coupled in series
`According to the invention the transmitter is con
`to a duplex circuit, the method comprising the steps of:
`(a) sequentially switching on power ampli?er sec
`nected on in a controlled sequence. This sequence can
`be started in advance to the transmitting period, so that
`tions so as to prevent a broad frequency spectrum
`the period timing of the pulsed operation is ful?lled.
`of the transmitter from arising in an initial transmis
`According to the invention the signal switching
`sion phase of the transmitter due to impedance
`order in the controlled sequence can be chosen in differ
`level changes at each transmitter power ampli?er
`ent ways, so that it suits the requirements and the opera
`section; and thereafter
`tion of the mobile phone in question.
`(b) switching on a transmit power control signal,
`In the preferred embodiment the power on sequence
`which enables a signal input to the transmitting
`is as follows (the digital mode is switched on, MODE
`power ampli?er sections coupled in series to be
`input enabling the digital operation):
`ampli?ed and output to the duplex circuit.
`1. The voltages to the power ampli?ers 3 and 4 are
`2. A method as in claim 1, wherein the step of sequen
`tially switching on comprises:
`switched on, controlled by the signal at the TXE (trans
`mit enable) terminal. At the same time collector volt
`switching on the output power ampli?er sections by
`ages to the preampli?er stages 1 and 2 are switched on.
`enabling a transmit enable signal; and thereafter
`2. The base voltages to the preampli?er stages 1 and
`switching on input power ampli?er sections by en
`2 are switched on with the signal at the RAMP-UP
`abling a ramp-up signal.
`terminal.
`3. A method as in claim 1, wherein the step of sequen
`3. The TXC (transmitter power control) signal is
`tially switching on comprises switching on the power
`switched on, controlling the output level at the ampli
`ampli?er sections (1-4) by enabling a transmit enable
`?er 4 output.
`signal (TXE) and a ramp-up signal (RAMP-UP).
`This sequential switching on ensures a stable opera
`4. A method as in claim 1, wherein said power ampli
`tion. The impedance levels of the transmitter stages is
`?er sections include preampli?er sections and power
`stabilized before the power control TXC, or the proper
`ampli?er sections, and further comprising the steps of:
`on-signal, is switched on. This sequence function also
`switching on collector voltages to said preampli?er
`stabilizes the synthesizer frequency control, due to the
`sections at the same time voltages to the power
`stable impedance levels.
`ampli?er sections are sequentially switched on,
`Alternatively it is contemplated to switch on the
`switching on base voltages to the preampli?er sec
`ampli?ers 1-4 in the sequence 1 - 2 - 3 - 4 - TXC. Still
`tions with a signal at a RAMP-UP terminal, and
`another possibility is to switch on the TXE and RAMP
`switching on a transmitter power control which con
`UP simultaneously and the TXC signal a short moment
`trols an output level at an output of said transmit
`ting power ampli?er sections.
`later when the ampli?er impedance levels are stabilized.
`Further it is conceivable to switch on the enable signal
`5. A method for providing a positive transmitter
`TXE in the ?rst stage (enabling the ampli?ers 3 and 4),
`power switch-on of a transmitter in a dual-mode mobile
`radiotelephone having programmable logic in the digi
`then in the second stage the RAMP-UP and TXC sig
`nals simultaneously. And of course it is still possible to
`tal mode for controlling switching-on of at least an
`switch on all transmit enabling signals TXE, RAMP
`input power ampli?er and output power ampli?er sec
`UP, TXC at the same moment. In all alternatives above
`tions coupled in series to a duplex circuit, the method
`it is supposed that the digital mode is enabled by the
`comprising the steps of:
`signal at the MODE terminal.
`a) switching on output power amplifier sections (3
`It is understood that the power switch-off presents no
`and 4) by enabling a transmit enable signal (T XE);
`major problems, as compared to those present at power
`and thereafter
`b) switching on input power ampli?er sections (1 and
`switch-on. Therefore the power can be switched off at
`all ampli?ers 1-4 essentially at the same moment.
`2) by enabling a ramp-up signal (RAMP-UP) so as
`The present invention provides the means to switch
`to prevent a broad frequency spectrum of the trans
`on the power of a dual-mode mobile radio telephone in
`mitter from arising in an initial transmission phase
`of the transmitter due to impedance level changes
`a controlled manner, so as to minimize the transmission
`irregularities at the power switch-on. Therefore, while
`at each transmitter power ampli?er section; and
`a particular embodiment of the invention has been de
`c) switching on a transmit power control signal
`scribed and shown, it should be understood that the
`(T XC), which enables a signal (RFIN) input to the
`transmitting power ampli?er sections coupled in
`invention is not limited thereto since many modi?ca
`tions may be made by those skilled in the art. It is there
`series (1-4) to be ampli?ed and output to the duplex
`fore contemplated to cover by the present application
`circuit (10).
`any and all such modi?cations that fall within the true
`6. A dual-mode mobile radiotelephone operated in
`spirit and scope of the basic underlying principles dis
`accordance with the method of any of the claims 1-4.
`closed and claimed herein.
`i t i i I!
`
`45
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`55
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`60
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`TCL EXHIBIT 1083
`Page 4 of 4