JP4258109B2 - Spread spectrum transmitter for multicode transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spread spectrum transmitter that performs multicode transmission.
[0002]
[Prior art]
An outline of a transmitter (RF unit) of a car phone (wireless communication terminal) using a conventional spread spectrum system will be described below with reference to FIG. The transmitter performs single code transmission. Hereinafter, the transmitter is referred to as a single code transmitter. The single code transmitter includes an attenuator 1, a power amplifier 2, a directional coupler 3, a terminator 4a, a detector (diode) 4b, a filter 5, an A-D converter 6, a microcomputer 7, a memory (non-volatile memory). ) 7a, a DA converter 8 and an operational amplifier 9.
[0003]
The attenuator 1 uses the modulated high-frequency signal as an input signal, attenuates the input signal by a predetermined attenuation amount, and outputs the amplified signal. The power amplifier 2 amplifies the output signal of the attenuator 1 with a preset gain, A transmission output signal is supplied to the antenna end side. The antenna end is an antenna mounting portion of a car phone. In addition, the directional coupler 3 is provided in the subsequent stage of the power amplifier 2, and the directional coupler 4 has one end connected to the terminator 4 a and the other end connected to the detector 4 b. The detector 4b receives a proportional signal having a voltage level proportional to the transmission output signal, and the detector 4b outputs a detection signal indicating the envelope level in the positive half wave of the proportional signal. The filter 5 smoothes the detection signal of the detector 4b and outputs a smooth signal. As described above, the detector 4 b performs power detection of the transmission output signal together with the filter 5.
[0004]
The A-D converter 6 performs analog-digital conversion on the smooth signal of the filter 5 and outputs a digital signal. The memory 7a has a transmission power map in advance, and the transmission power map holds transmission power data (for example, 75) for each target transmission power level. However, the target transmission power level (the target value of the power of the transmission output signal) is obtained from the power control signal from the communication network side. Further, the microcomputer 7 selects transmission power data corresponding to the target transmission power level from the transmission power map of the memory 7a, obtains a difference between the transmission power data and the digital signal from the A / D converter 6, A difference signal corresponding to the difference is output.
[0005]
The DA converter 8 performs digital-analog conversion on the differential signal from the microcomputer 7 and outputs an analog signal to the attenuator 1. The attenuator 1 converts the input signal into a predetermined attenuation amount corresponding to the analog signal. Only attenuated output. That is, the attenuation amount of the attenuator 1 is controlled by the microcomputer 7 so as to be a constant level according to the target transmission power level. Hereinafter, the transmission power map of the memory 7a will be described.
[0006]
At the time of transmission by a single code transmitter, the power gain from the attenuator 1 to the antenna end differs for each target transmission power level. Further, the power gain from the attenuator 1 to the antenna end side differs for each car phone product. In addition, the temperature change characteristic (due to heat generation) of the power gain with respect to the target transmission power level is different for each product of the car phone. For this reason, at the time of manufacture of the automobile phone, each transmission power data corresponding to each target transmission power is stored in the transmission power map of the memory 7a for each product. Thereby, the single code transmitter can accurately control the transmission power so as to keep the target transmission power level constant.
[0007]
[Problems to be solved by the invention]
Recently, spread spectrum communication for performing multicode transmission has been proposed, and the present inventor has proposed a transmitter for a mobile phone (wireless communication terminal) using a spread spectrum system (W-CDMA system) for performing multicode transmission. Was examined based on the single code transmitter. Hereinafter, a mobile phone transmitter using a spread spectrum system that performs multi-code transmission as studied by the present inventor (hereinafter simply referred to as a multi-code transmitter) will be described with reference to FIGS.
[0008]
As shown in FIG. 4, the multicode transmitter includes multipliers 11 to 18, adders 20 and 21, multipliers 30 and 31, phase shifter 32, digital filters (FIR) 33 and 34, local oscillator (Lo). ) 35, 36, a quadrature modulator 40 with a variable gain amplifier, and a band pass filter 50. The quadrature modulator with variable gain amplifier 40 includes multipliers 41 and 42, a phase shifter 43, an adder 44, and a gain control amplifier 45.
[0009]
As shown in FIG. 5, the multi-code transmitter includes a local oscillator (Lo) 36, a band pass filter 51, a multiplier 52, a gain control amplifier 60, a band pass filter 70, an amplifier 80, a directional coupler. 90, an isolator 91, a duplexer 92, an antenna 93, a detector 100, a filter 110, an A / D converter 120, a microcomputer 130, a memory 140, and a D / A converter 150 are provided. The local transmitters (Lo) 35 and 36 are each composed of a PLL circuit.
[0010]
First, as input signals to the multicode transmitter shown in FIG. 4, a first transmission signal (DPDCH1: dedicated Physical Data Channel 1), a third transmission signal (DPDCH3: dedicated Physical Data Channel 3), and a second transmission signal ( DPDCH2: dedicated Physical Data Channel 2) and control signal (DPCCH: dedicated Physical control Channel) are employed. The first transmission signal DPDCH1 is obtained by serial-parallel conversion of serial communication data together with the third transmission signal DPDCH3 and the second transmission signal DPDCH2, and the first to third transmission signals (DPDCH1). , DPDCH2, and DPDCH3) are variable rates, but are the same rate. The control signal has a synchronization signal for synchronizing the automobile telephone and the communication network side (base station), and the rate of the control signal is a fixed rate.
[0011]
In the example shown in FIG. 4, the number of transmission signals (DPDCH1 to DPDCH3) (hereinafter referred to as the number of channels) is “four”, but the number of input transmission signals (DPDCH) changes. ing. Specifically, (1) the first to third transmission signals are stopped and only the control signal is input. (2) Input of the second and third transmission signals is stopped, and only the first transmission signal and the control signal are input. (3) Input of the third transmission signal is stopped, and only the first and second transmission signals and the control signal are input. (4) All of the first to third transmission signals and the control signal are input. As described above, in the multicode transmitter, only the control signal is always input, but at least one transmission signal (DPDCH) is selectively input or input is stopped. Hereinafter, an example in which all of the first to third transmission signals and the control signal are input in the multicode transmitter will be described.
[0012]
The multiplier 11 spreads the spectrum of the first transmission signal DPDCH1 with the first spreading code (Cd1: Channelization Code 1) and outputs the first spread signal. The multiplier 12 multiplies the first spread signal by the first gain parameter βd (first coefficient) and outputs a first multiplication signal. The multiplier 13 spreads the spectrum of the third transmission signal DPDCH3 using a third spreading code (Cd3: Channelization Code 3) and outputs a third spread signal. The multiplier 14 multiplies the third spread signal by the first gain parameter βd (first coefficient) and outputs a third multiplication signal. The adder 20 adds the first and third multiplication signals and outputs a first addition signal.
[0013]
The multiplier 15 spreads the spectrum of the second transmission signal DPDCH2 using a second spreading code (Cd2: Channelization Code 2) and outputs a second spread signal. The multiplier 16 multiplies the second spread signal by the first gain parameter βd (first coefficient) and outputs a second multiplication signal. The multiplier 17 spreads the control signal DPCCH with a fourth spreading code (Cc) and outputs a fourth spread signal. The multiplier 18 multiplies the second spread signal and the second gain parameter βc (second coefficient) and outputs a fourth multiplication signal. The adder 21 adds the second and fourth multiplication signals and outputs a second addition signal.
[0014]
Next, the first and second gain parameters βd and βc will be described. First, a receiver of a base station of a communication network receives a transmission signal from a car phone and performs despreading processing on the first to fourth multiplication signals based on this transmission signal. In despreading the first multiplication signal, the second to fourth multiplication signals become interference signals, and in despreading the second multiplication signal, the first, third, and fourth multiplication signals are interference signals. It becomes. Similarly, when despreading the third multiplication signal, the first, second, and fourth multiplication signals become interference signals, and when despreading the fourth multiplication signal, the first to third multiplication signals are It becomes a disturbing signal. For this reason, if the power of each of the first to fourth multiplication signals is not uniform, it is difficult to perform the despreading process of each of the first to fourth multiplication signals satisfactorily.
[0015]
Here, since the rate of the control signal is a fixed rate, the power of the fourth spread signal is constant, but the first to third transmission signals (DPDCH1, DPDCH2, and DPDCH3) are each as described above. Since it has a variable rate, each power of the first to third spread signals changes according to a change in the rate. Therefore, the first and second gain parameters βd and βc are set so that the sum of each power of the first to fourth multiplication signals (bit energy per bit of the first to fourth multiplication signals) is kept constant. The respective powers of the first and fourth multiplication signals (the bit energy per bit of the first multiplication signal and the bit energy per bit of the fourth multiplication signal) are matched. Accordingly, as described above, since the rates of the first to third transmission signals are the same, the respective powers of the first to fourth multiplication signals match. As described above, since the respective powers of the first to fourth multiplication signals are matched, the despreading processing of each of the first to fourth multiplication signals can be satisfactorily performed in the receiver of the base station of the communication network. .
[0016]
The multiplier 30 multiplies the first addition signal from the adder 20 by the long code. The long code is a scramble code and is a unique code for each automobile telephone (wireless communication terminal), and serves to identify the automobile telephone on the communication network side. The scramble code may be a short code instead of the long code.
[0017]
The digital filter (FIR) 33 receives the output signal from the multiplier 30 and outputs a filter signal. The phase shifter 32 receives the long code and outputs an output signal obtained by shifting the phase of the long code by 90 °. The multiplier 31 outputs the second addition signal from the adder 21 to the second addition signal from the phase shifter 32. Is multiplied by the output signal of. The digital filter (FIR) 34 receives the output signal from the multiplier 31 and outputs a filter signal.
[0018]
Here, in the quadrature modulator 40 with variable gain amplifier, the filter signal from the digital filter (FIR) 33 is input as the real component I, and the filter signal from the digital filter (FIR) 34 is input as the imaginary component Q. Then, quadrature modulation is performed based on filter signals from both digital filters (FIR) 33 and 34. Specifically, the multiplier 41 multiplies the filter signal from the digital filter (FIR) 33 and the carrier wave signal from the local oscillator (Lo) 35. That is, the multiplier 41 converts the filter signal of the digital filter 33 into a signal having a higher frequency than the filter signal. The phase shifter 43 receives the carrier signal from the local oscillator (Lo) 35 and outputs a phase shift carrier signal obtained by shifting the phase of the carrier signal by 90 °. The multiplier 42 multiplies the filter signal from the digital filter (FIR) 34 and the phase shift carrier signal from the phase shifter 43. The adder 44 adds the output signals from both the multipliers 41 and 42 and outputs the addition signal as a quadrature modulation signal.
[0019]
The gain control amplifier 45 power-amplifies the quadrature modulation signal (addition signal) with a variable gain corresponding to the analog signal from the DA converter 150 and outputs a transmission output signal. The bandpass filter 50 receives the transmission output signal of the gain control amplifier 45 and outputs a filter signal. The multiplier 52 multiplies the filter signal of the bandpass filter 50 and the frequency signal from the local oscillator (Lo) 36. . That is, the multiplier 52 converts the filter signal of the bandpass filter 50 into a signal having a higher frequency than that of the filter signal.
[0020]
The band pass filter 51 receives the output signal from the multiplier 52 and outputs a filter signal. The gain control amplifier 60 amplifies the power of the filter signal of the bandpass filter 51 with a variable gain corresponding to the digital signal from the DA converter 150 and outputs an amplified signal. The band pass filter 70 receives the amplified signal from the gain control amplifier 60 and outputs a filter signal. The amplifier 80 amplifies the power of the filter signal from the bandpass filter 70 with a preset gain. An output signal of the amplifier 80 is output to the antenna 93 through the directional coupler 90, the isolator 91, and the duplexer 92. Thereby, the output signal of the amplifier 80 is output using electromagnetic waves (radio waves) as a medium.
[0021]
The detector 100 (diode) plays a role similar to that of the detector 4 b shown in FIG. 3, and the detector 100 receives an output proportional signal from the directional coupler 90, and the output proportional signal is The voltage level is proportional to the output signal. The detector 100 outputs a detection signal (DC voltage) indicating the envelope level of the positive half wave of the output proportional signal. The filter 110 plays the same role as the filter 5 shown in FIG. 3 and smoothes the detection signal of the detector 100 to output a smooth signal.
[0022]
The AD converter 120 performs analog-digital conversion on the smooth signal from the filter 110 and outputs a digital signal. The memory (transmission power map) 140 holds a plurality of transmission power data to be described later, and the microcomputer 130 performs control according to the transmission power data of the memory 140 and the digital signal from the AD converter 120. Output a signal. The DA converter 150 converts the control signal from the microcomputer 7 from digital to analog and outputs the analog signal to the gain control amplifiers 45 and 60. Thus, the gain control amplifier 45 is controlled so as to keep the power of the transmission output signal at the target transmission power level in accordance with the control signal from the microcomputer 130. Accordingly, the gain control amplifier 60 is controlled to keep the power of the amplified signal constant according to the control signal from the microcomputer 130.
[0023]
Hereinafter, transmission power data of the memory 140 will be described. In the single code transmitter described above, as shown in FIG. 7, a voltage waveform (see B in FIG. 7) corresponding to the target transmission power level is obtained as the detection signal of the detector 4b. However, a DC voltage waveform corresponding to the target transmission power level can be obtained. Therefore, in the transmission power control by the microcomputer 7, the digital signal after A / D conversion in the smooth signal of the filter 5 and the transmission power data for each target transmission power level in the memory 7a are employed. That is, the memory 7a is provided with only one type of transmission power map having transmission power data for each target transmission power level. However, according to the study by the present inventor, it has been found that a multi-code transmitter requires a plurality of types of transmission power maps as the transmission power map of the memory 140. As shown in FIGS. 8 and 9, the first to fourth multiplication signals (see symbols D <b> 1 to D <b> 4 in FIGS. 8 and 9) due to changes in the first and second gain parameters βd and βc. , The voltage waveform of the amplified signal of the gain control amplifier 60 (see symbol C) changes, and the voltage waveform of the detection signal of the detector 100 (see symbol E in FIGS. 8 and 9) changes. Because. In the example shown in FIGS. 8 and 9, the amplitude level of the first to third multiplication signals changes from the code DL in FIG. 8 to the code DL ′ in FIG. 9, and the amplitude of the fourth multiplication signal. The level changes from the code DR in FIG. 8 to the code DR ′ in FIG. 9, and the amplitude level of the amplified signal of the gain control amplifier 60 changes from the code CL1 to CL3 in FIG. It changes to CL3 ′, and the amplitude level of the detection signal of the detector 100 changes from the symbols EL1 to EL3 in FIG. 8 to the symbols EL1 ′ to EL3 ′ in FIG.
[0024]
Next, a specific example in which the detection signal of the detector 100 changes due to changes in the first and second gain parameters βd and βc will be described. First, an example in which all of the first to third transmission signals and the control signal are input will be described. Here, as described above, the first and second gain parameters βd and βc set the powers of the first to fourth multiplication signals while keeping the total power of the first to fourth multiplication signals constant. Set to match. The maximum values of the first and second gain parameters βd and βc are “1”.
[0025]
  For example, when the rate of the control signal is 15 Kbps and the rates of the first to third transmission signals are 120 Kbps, the first gain parameter is used to match the powers of the first to fourth multiplication signals. βd is “0.32”, and the second gain parameter βc is “0.04”. When the rates of the first to third transmission signals change from 120 Kbps to 240 Kbps, as described above, the first to fourth multiplications are performed while keeping the total power of the first to fourth multiplication signals constant. In order to match each power of the signal, the first gain parameter βd becomes “0.326”, and the second gain parameter βc becomes “0.326”.0.022" As described above, when the rates of the first to third transmission signals change, the first and second gain parameters βd and βc change.
[0026]
Here, since the voltage waveform of the amplified signal of the gain control amplifier 60 is based on the sum of the first to fourth multiplication signals (see symbols D1 to D4 in FIG. 8), the voltage waveform of the amplified signal is It changes based on changes in the first to third transmission signals. That is, even if the average transmission power transmitted from the antenna 93 remains constant, the voltage waveform of the amplified signal changes depending on the combination of the first and second gain parameters βd and βc as described above. The voltage waveform of the 100 detection signals (see symbol E in FIG. 8) varies with the combination of the first and second gain parameters βd and βc together with the voltage waveform after the filter 110 is smoothed. Therefore, it is necessary to prepare a plurality of transmission power maps corresponding to the combination of the first and second gain parameters βd and βc.
[0027]
Also, the transmission power map needs to be prepared corresponding to the number of channels {number of transmission signals (DPDCH)}. However, when any of the first to third transmission signals is stopped, a multiplication signal corresponding to the input transmission signal (DPDCH) (hereinafter referred to as a corresponding multiplication signal), a fourth multiplication signal, The first and second gain parameters βd and βc are set so as to keep the sum of the respective powers constant and to make the powers of both the corresponding multiplication signal and the fourth multiplication signal coincide. Further, the input transmission signal has a variable rate of the same value as described above.
[0028]
  For example,(1)When the first to third transmission signals are stopped and only the control signal (rate: 15 Kbps) is input, the second gain parameter βc becomes “1”.(2)When the second and third transmission signals are stopped and only the first transmission signal (rate: 120 Kbps) and the control signal (rate: 15 Kbps) are input, the first and second gain parameters βd and βc are Since the sum of the powers of the first and fourth multiplication signals is constant and the powers of the first and fourth multiplication signals are set to coincide with each other, the first gain parameter βd is set to “0.88”And the second gain parameter βc is“0.11"
[0029]
  (3)When the third transmission signal is stopped and only the first and second transmission signals (rate: 120 Kbps) and the control signal (rate: 15 Kbps) are input, the first and second gain parameters βd and βc are Since the sum of the powers of the first, second, and fourth multiplication signals is constant and the powers of the first, second, and fourth multiplication signals are set to match, the first gain parameter βd But"0.471”And the second gain parameter βc is“0.058"
[0030]
  (4)When all of the first to third transmission signals (rate: 120 Kbps) and the control signal (rate: 15 Kbps) are input, the first and second gain parameters βd and βc are the first to fourth multiplication signals. The sum of the powers is constant, the powers of the first to fourth multiplication signals are set to coincide with each other, the first gain parameter βd is “0.32”, and the second gain parameter βc is “0.04”. .
[0031]
  Thus, when the number of channels is “4”,(1)~(4)The combinations of the first and second gain parameters βd and βc change every four ways depending on the rates of the first to third transmission signals. Therefore, even if the average transmission signal power transmitted from the antenna 93 remains constant, the voltage waveform obtained by smoothing the voltage waveform of the detection signal of the detector 100 by the filter 110 is the first and second gain parameters βd, Since it varies depending on the combination of βc, it is necessary to prepare a transmission power map corresponding to the number of channels.
[0032]
As described above, it is necessary to prepare a transmission power map corresponding to the combination of the first and second gain parameters βd and βc in addition to the number of channels. Specifically, if the first and second gain parameters βd and βc are 16 and the number of channels is 4, 64 types of transmission power maps are required (16 × 4 = 64). . That is, as shown in FIG. 10, assuming that 75 transmission power data of {24 dBm to −50 dBm (in the case of 1 dBm step)} are held in one transmission power map, 4800 transmission power data are stored. This is necessary, and the memory 140 requires an excessive capacity.
[0033]
An object of the present invention is to provide a spread spectrum transmitter that performs multicode transmission in which the capacity of the data holding means is reduced.
[0034]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, a fixed-rate control signal is spectrum-spread to output a control-spread signal, and the three transmission signals having the same rate are changed by changing the rate. Spreading means (11, 13, 15, 17) for spreading the spectrum and outputting three transmission spread signals;
  Multiplication means for multiplying each of the three transmission spread signals by a first coefficient (βd) to obtain three transmission multiplication signals and multiplying the control spread signal by a second coefficient (βc) to obtain a control multiplication signal (12, 14, 16, 18)
  The first and second coefficients (βd, βc) are the three transmission multiplication signals and the control multiplication signal.Bit energy per bitIs kept constant and any one of the three transmission multiplication signals isBit energy per bitAnd the control multiplication signalBit energy per bitAre set to match each other,
  A first adder (20) for adding two transmission multiplication signals out of the three transmission multiplication signals and outputting a first addition signal;
  A second adder (21) for adding the remaining one transmission multiplication signal among the three transmission multiplication signals and the control multiplication signal to output a second addition signal;
  Quadrature modulation means (41 to 44) for performing quadrature modulation and outputting quadrature modulation signals in accordance with the first and second addition signals;
  A power amplifier (45) for amplifying power with a variable gain according to the quadrature modulation signal and outputting a transmission output signal;
  Average signal output means (100, 110A) for outputting an average signal corresponding to the average value of the power of the transmission output signal according to the transmission output signal;
  Data holding means (140) for holding transmission power data for each target value of power of the transmission output signal;
  Control means (130) for controlling the variable gain of the power amplifier so that the power of the transmission output signal becomes constant according to the transmission power data and the average signal.A spread spectrum transmitter
  A rear-stage variable gain amplifier (60) provided on the rear stage side of the power amplifier and outputting a power amplified signal by amplifying power with a variable gain according to the transmission output signal;
  The control means controls the variable gain of the post-stage variable gain amplifier so that the power of the power amplification signal becomes constant according to the transmission power data and the average signal,
  The average signal output means includes
  A detector (100) for outputting an envelope signal corresponding to an envelope level in a half wave of the power amplification signal in response to the power amplification signal from the latter-stage variable gain amplifier;
  Average smoothing means (110A) for smoothing the envelope signal so as to average the envelope level and outputting the average signal;
  The average smoothing means includes a first resistance element (111) connected to the output terminal of the detector, and a first capacitor (112) connected between one end of the first resistance element and the ground. ), A second capacitor (113) connected between the other end of the first resistance element and the ground, and the first capacitor between one end of the first resistance element and the ground, A second resistive element (114) connected in parallel,
  The transmission power data for each target value of power of the transmission output signal held in the data holding means (140) is measured at the time of single code transmission.
[0035]
As described above, the average signal of the average signal output means is employed in controlling the variable gain of the power amplifier. Here, when the transmission signal stops transmission, the waveform of the transmission output signal changes.When transmission starts from the stop state of the transmission signal, the waveform of the transmission output signal changes.When the transmission signal rate changes, the transmission output signal waveform changes. Although the waveform changes, the average signal corresponds to the average value of the power of the transmission output signal. Therefore, in the state where the power of the transmission output signal is constant, the average signal is almost equal to the power of the transmission output signal. It becomes constant. Therefore, as in the conventional single code transmitter, as the data holding means, as described above, only the transmission power data for each target value of the power of the transmission output signal is held, so the capacity of the data holding means is reduced. Can be reduced.
[0039]
In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments shown in the drawings will be described below. The transmitter of a spread spectrum communication (W-CDMA system) car phone that performs multi-code transmission in this embodiment has the same block configuration as that shown in FIGS. However, unlike the filter 110 shown in FIG. 4, the filter 110A shown in FIG. The filter 110A smoothes the detection signal so as to average the voltage level of the detection signal (envelope signal) from the detector 100, and outputs an average signal. However, the average signal indicates the average power value of the output signal of the amplifier 80.
[0041]
The filter 110A employs a resistance element 114 in addition to the resistance element 111 and the capacitors 112 and 113 shown in FIG. The resistance element 111 is connected between the detector 100 and the AD converter 120, and the resistance element 114 and the capacitor 112 are respectively connected between the output terminal of the detector 100 and the ground. The capacitor 113 is connected between the input terminal of the AD converter 120 and the ground.
[0042]
The A-D converter 120 converts the average signal of the filter 110A into a digital signal, and the microcomputer 130 responds to the digital signal from the A-D converter 120 and the transmission power data of the memory 140. The gain control amplifiers 45 and 60 are controlled. Thereby, the gain control amplifiers 45 and 60 are controlled so as to keep the power of the output signal (transmission output signal and amplified signal) constant according to the control signal from the microcomputer 130.
[0043]
As described above, in the power control of the output signals of the gain control amplifiers 45 and 60, the digital signal of the average signal (from the AD converter 120) is adopted, and the average signal is the power average of the output signal of the amplifier 80. In the state where the average transmission power transmitted from the antenna 93 is constant, the voltage level of the average signal becomes substantially constant even if the voltage waveform of the amplified signal of the gain control amplifier 60 changes. Accordingly, only one type of transmission power data for each target value of the power of the transmission output signal needs to be prepared in the memory 140 as in the conventional single code transmitter. Thereby, it is not necessary to prepare a transmission map under various conditions, and the capacity of the memory 140 can be reduced.
[0044]
As a transmission map, each transmission power data is obtained by measuring each transmission power corresponding to each target transmission power for each product of a car phone at the time of manufacture. Here, in order to prepare a transmission map under various conditions, it is necessary to measure each transmission power corresponding to each target transmission power under various conditions. In this embodiment, as described above, transmission is performed. Since only one type of transmission power data for each target value of output signal power needs to be prepared, the number of times of measurement can be reduced.
[0045]
Note that the voltage level of the average signal of the filter 110A of the present embodiment (multicode transmitter) is slightly higher than the voltage level of the smooth signal of the filter 110 (single code transmitter). The microcomputer 130 according to the present embodiment controls the power of the output signals of the gain control amplifiers 45 and 60 in accordance with the digital signal of such an average signal. Therefore, when the same transmission power target value is set, the present embodiment In the embodiment, an effect that the transmission power can be reduced can be expected as compared with the single code transmitter (see FIG. 2).
[0046]
In the above embodiment, as illustrated in FIG. 4, an example in which four transmission signals (DPDCH) are employed has been described. . For example, when only one transmission signal (DPDCH1) is employed, the adders 20 and 21 are deleted, and the first multiplication signal is directly input to the multiplier 30 instead of the first addition signal. The Further, the fourth multiplication signal (control signal) is directly input to the multiplier 30 instead of the second addition signal. Other configurations are substantially the same as those of the above embodiment.
[0047]
In such a configuration, (1) when one transmission signal (DPDCH1) and control signal (DPCCH) are input, and (2) input of the transmission signal (DPDCH1) is stopped and control signal (DPCCH) When only the signal is input, the voltage waveform of the detection signal of the detector 100 is different. Accordingly, since the voltage waveform of the detection signal of the detector 100 changes while the average transmission power transmitted from the antenna 93 is constant, the voltage level of the average signal of the filter 110A becomes constant. Similarly, only one transmission power map is employed, and the capacity of the memory 140 can be reduced.
[0048]
In implementing the present invention, the spread spectrum transmitter that performs multicode transmission is not limited to a car phone, and may be applied to various wireless communication devices such as a mobile phone.
[Brief description of the drawings]
FIG. 1 is an electric circuit diagram showing a detector and a filter of a transmitter according to an embodiment of the present invention.
FIG. 2 is a diagram for illustrating the effect of the transmitter.
FIG. 3 is a block diagram showing an electric circuit configuration showing a conventional transmitter.
FIG. 4 is a block diagram showing an electric circuit configuration showing a part of the transmitter.
FIG. 5 is a block diagram showing an electric circuit configuration showing the rest of the transmitter.
6 is an electric circuit diagram showing a specific configuration of the filter shown in FIG. 5;
7 is a diagram for explaining the operation of the filter 5 shown in FIG. 5; FIG.
8 is a diagram for explaining the operation of the filter 100 shown in FIG.
9 is a diagram for explaining the operation of the filter 100 shown in FIG.
10 is a diagram for explaining the memory shown in FIG. 5. FIG.
[Explanation of symbols]
80 ... Amplifier, 100 ... Detector, 140 ... Memory.

Claims (1)

Spreading means (11) that spreads a spectrum of a fixed rate control signal and outputs a control spread signal, spreads three transmission signals having the same rate and the same rate, and spreads the three transmission spread signals. , 13, 15, 17),
Multiplication means for multiplying each of the three transmission spread signals by a first coefficient (βd) to obtain three transmission multiplication signals and multiplying the control spread signal by a second coefficient (βc) to obtain a control multiplication signal (12, 14, 16, 18)
The first and second coefficients (βd, βc) keep the sum of bit energy per bit of the three transmission multiplication signals and the control multiplication signal constant, and any of the three transmission multiplication signals one per bit and bit energy to bit energy per bit of the control multiplied signal is set so as to coincide respectively or,
A first adder (20) for adding two transmission multiplication signals out of the three transmission multiplication signals and outputting a first addition signal;
A second adder (21) for adding the remaining one transmission multiplication signal among the three transmission multiplication signals and the control multiplication signal to output a second addition signal;
Quadrature modulation means (41 to 44) for performing quadrature modulation and outputting quadrature modulation signals in accordance with the first and second addition signals;
A power amplifier (45) for amplifying power with a variable gain according to the quadrature modulation signal and outputting a transmission output signal;
Average signal output means (100, 110A) for outputting an average signal corresponding to the average value of the power of the transmission output signal according to the transmission output signal;
Data holding means (140) for holding transmission power data for each target value of power of the transmission output signal;
In response to said transmission power data the average signal and, a said control means power of the transmission output signal controls the variable gain of the power amplifier to be constant (130) and a spread spectrum transmitter to have a ,
A rear-stage variable gain amplifier (60) provided on the rear stage side of the power amplifier and outputting a power amplified signal by amplifying power with a variable gain according to the transmission output signal;
The control means controls the variable gain of the post-stage variable gain amplifier so that the power of the power amplification signal becomes constant according to the transmission power data and the average signal,
The average signal output means includes
A detector (100) for outputting an envelope signal corresponding to an envelope level in a half wave of the power amplification signal in response to the power amplification signal from the latter-stage variable gain amplifier;
Average smoothing means (110A) for smoothing the envelope signal so as to average the envelope level and outputting the average signal;
The average smoothing means includes a first resistance element (111) connected to the output terminal of the detector, and a first capacitor (112) connected between one end of the first resistance element and the ground. ), A second capacitor (113) connected between the other end of the first resistance element and the ground, and the first capacitor between one end of the first resistance element and the ground, A second resistive element (114) connected in parallel,
The transmission power data for each target value of the power of the transmission output signal held in the data holding means (140) is measured at the time of single code transmission, spread spectrum transmission for performing multicode transmission Machine.

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