JPH11205162A - Multi-carrier transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-carrier transmitter with a reduced circuit scale and power consumption which enables ALC control over a wide dynamic range at a lower cost. SOLUTION: This multi-carrier transmitter is provided with first and second modulators 3 and 6 for respectively modulating data by first and second high frequency signals from first and second local oscillators 2 and 5 and for generating first and second modulation waves; first and second variable gain amplification parts 4 and 7 for amplifying the first and second modulation waves with variable gains; a synthesis part 8 for synthesizing the two modulation waves; a distribution part 9 for distributing the output of the synthesis part 8 and supplying one of it to an antenna; a frequency conversion part 11 for inputting the other one of the distributed output and for frequency-converting the first and second modulation waves extracted for the ALC control to first and second intermediate frequencies by the high frequency signals from a third local oscillator 12; and an ALC circuit 13 for receiving transmitted output control signals and the first and second intermediate frequencies, for performing a comparison arithmetic processing and outputting first and second control voltages to the variable gain amplifiers 4 and 7. The output level of the first and second modulation waves is kept fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-carrier transmitter, and more particularly to a multi-carrier transmitter for saving space and reducing power consumption.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing an example of a configuration of a conventional multicarrier transmitter of a TDMA (time division multiple access) system. Referring to FIG. 9, different high-frequency signals a and b output from the local oscillators 2 and 5 are:
The modulators 3 and 6 perform data modulation to generate modulated waves a and b. Next, the modulated waves a and b are amplified by the variable gain amplifying units 4 and 7 and the distribution units 37 and 3 for amplifying the gain according to the control voltages 59 and 60.
The signal is output from the antenna 10 via the synthesizing unit 8 and the synthesizing unit 8.

[0003] For ALC (automatic level control) control, detectors 39 and 40 transmit modulated waves c and c from distribution units 37 and 38, respectively.
d is input, and DC voltages 43 and 44 corresponding to the power levels of the modulated waves c and d are output. The DC voltages 43 and 44 are converted into digital data 45 and 46 by A / D converters 41 and 42.

The digital data 45 and 46 are stored in a CPU 47,
CPU (Central Processing Unit) 47, 48
Is a transmission output control signal 49 transmitted by the host device,
ROMs (read-only memories) 51 and 52 for converting the data 50 and storing the converted data as transmission output control signal data 53 and 54;
The transmission output control signals 49 and 50 are recognized, and the ROMs 51 and 5 are recognized.
2, the transmission output control signal data 53 and 54 are read out,
The input digital data 45 and 46 and the transmission output control signal data 53 and 54 are constantly monitored, and a comparison operation is performed so as to be the same, and control voltage data 55 and 56 are generated and output. More specifically, the CPUs 47 and 48 receive the digital data 45 and 46, read the transmission output control signal data 53 and 54 stored in the ROM 17 in advance, detect the power levels of the modulated waves c and d, and The transmission output control signal data 53, 54 and the digital data 45, 46 are constantly monitored by the transmission output control signals 49, 50 transmitted from the controller, and comparison operation processing is performed so as to be the same, and the control voltage data 55, 56 Generate and output

The control voltage data 55 and 56 are converted into control voltages 59 and 60 by D / A converters 57 and 58. An ALC control loop is provided for each frequency.

[0006]

However, the conventional multicarrier transmitter shown in FIG. 9 has the following problems.

[0007] The first problem is that circuit space is increased and power consumption is increased.

The reason is that the transmission line for detection is not shared,
This is because the ALC control loop is configured by an individualized circuit.

[0009] The second problem is that it is difficult to perform ALC control with a wide dynamic range.

[0010] The reason is that LOG-
This is because detection is not performed by the LINER amplifier.

The third problem is that the cost of configuring a circuit is high.

The reason is that when the output power is low, it is necessary to use a zero-bias diode or to use a drive amplifier for driving a detection diode.

[0013] Accordingly, the present invention has been made in view of the above problems, and has as its object to reduce the circuit scale and power consumption, and to enable ALC control with a wide dynamic range. An object of the present invention is to provide a multi-carrier transmitter for reducing costs.

[0014]

According to the present invention, there is provided a TDMA (time division multiple access) type multi-carrier transmitter which achieves the above object.
vel Control (automatic level control) is characterized in that space is saved and power consumption is reduced by sharing a loop.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment of the present invention. Referring to FIG. 1, in an embodiment of the present invention, first and second local oscillators 2, 5
Different first and second high-frequency signals a,
b is data-modulated by the first and second modulators 3 and 6, respectively, to generate first and second modulated waves a and b. Next, the first and second modulated waves are converted into first and second variable gain amplifiers 4 and 7 and two modulated waves that amplify to gains according to the first and second control voltages 26 and 27. A synthesis unit 8 for synthesis;
Via the distribution unit 9, one is the antenna 10 and the other is A
It is output to the frequency converter 11 for LC control.

The first and second modulated waves a and b extracted for the ALC control are converted into a first high frequency signal c and a second high frequency signal c from a third local oscillator 12 in a frequency conversion unit 11. The frequency is converted to intermediate frequencies c and d.

The ALC circuit 13 has a transmission output control signal 21
And the first and second intermediate frequencies c and d are input to perform a comparison operation process, and output first and second control voltages 26 and 27,
The output levels of the first and second modulated waves a and b can be kept constant.

The output control of the two different high-frequency signals is performed by an independent ALC circuit loop.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

Referring to FIG. 1, a multi-carrier transmitter 1 according to the present embodiment includes first and second local oscillators 2 and 5 for outputting different high-frequency signals a and b, and high-frequency signals a and b.
And first and second modulators 3 and 6 for performing data modulation to generate first and second modulated waves a and b, and applying first and second control voltages 26 to the modulated waves a and b, respectively. 27, first and second variable gain amplifying sections 4 and 7 for amplifying the gain according to 27,
b and a modulating waves a and b to the antenna 10 on one side and a third high frequency signal e from the third local oscillator 12 on the other side to the first and second intermediate frequencies c and d. An ALC function for inputting the intermediate frequency c and d and the transmission output control signal 21 and performing a comparison operation process so that the control voltages 26 and 27 become predetermined values. Is provided.

FIG. 2 is a diagram showing an example of the configuration of the ALC circuit 13 shown in FIG.

Referring to FIG. 2, ALC circuit 13 has a band-pass filter characteristic having a center frequency of intermediate frequency c and a band of a modulated wave, and generates DC voltage 15 corresponding to the power level of intermediate frequency c. First LOG to output
A (logarithmic) -LINER (linear) amplifier unit 14 and a DC voltage 29 having a band-pass filter characteristic having a center frequency of an intermediate frequency d and a band of a modulated wave, and corresponding to the power level of the intermediate frequency d A second LOG (log) -LINER (linear) amplifier unit 28 and a DC voltage 1
First and second A / D converters 16 and 30 for converting into digital data 22 and 31 corresponding to 5 and 29, and the characteristics of input power level-digital data 22 and 31 at intermediate frequencies c and d are stored in advance. Recognizing the ROM 17 and the transmission output control signal 21 sent from the host device,
Read out the transmission output control signal data 23 from the OM 17,
The comparison operation of the digital data 22 and the transmission output control signal data 23 corresponding to the intermediate frequency c and the digital data 31 and the transmission output control signal data 23 corresponding to the intermediate frequency d are performed independently, and the control voltage data 19 and 20 are controlled.
(CPU) 18 for generating and outputting
And control voltage 2 corresponding to control voltage data 19 and 20
First and second D / A converters 2 for converting into 6, 27
4 and 25.

For example, when the amplification degree of the first variable gain amplifying section 4 changes (increases) due to temperature fluctuation or the like, the flow of the signal of the modulated wave a depends on the intermediate frequency converted by the frequency converting section 11. The power level of c increases, and the DC voltage 15 increases proportionally.

Since the digital data 22 converted by the first A / D converter 16 is different from the value of the transmission output control signal data 23 before the fluctuation, the CPU 18 converts the digital data 22 into the same value.
Performs the comparison operation, and changes to the control voltage data 19 smaller than the previous value, and the control voltage 26 changes. Therefore, the gain of the first variable gain amplifying unit 4 is reduced, and the output power returns to the value before the change. Thus, the ALC control is performed.

On the other hand, the flow of the signal of the modulated wave b is divided into the second local oscillator 5, the second modulator 6, the second variable gain amplifier 7, the intermediate frequency d, and the second LOG-LINER amplifier 28. , DC voltage 29, second A / D converter 30, digital data 31, control voltage data 20, second D / A
The same operation is performed by the converter 25 and the control voltage 27. The reaction speed of the loop corresponds to each slot timing, and ALC control for each slot is also possible.

Next, regarding the operation of the present embodiment shown in FIG. 1, the relationship between the control voltage and the output power of the variable gain amplifiers 4 and 5 shown in FIG. 3 and the operation status of the multicarrier transmitter 1 shown in FIG. Time chart, LOG-LINER shown in FIG.
The relationship between the power levels of the intermediate frequencies c and d and the DC voltages 15 and 29 in the amplifier units 14 and 28, the relationship between the input data and the output voltage of the D / A converters 16 and 30 shown in FIG. Input voltage-output data of D converters 24 and 25
This will be described with reference to the relationship between data.

Hereinafter, TDMA-FD is used as an access method.
An embodiment in which the present invention is applied to a multicarrier transmitter employing the D system (PDC half rate) will be described in detail with reference to the drawings.

First, when only carrier 1 is transmitted (T
S # 0).

High frequency signal a output from local oscillator 2
(810 MHz) is modulated by the modulator 3 to generate a modulated wave a (810 MHz). Next, the modulated wave a
Is the antenna 1 via the variable gain amplifying unit 4 for amplifying the gain according to the control voltage 26, the synthesizing unit 8, and the distribution unit 11.
Output from 0. On the other hand, in the ALC control, the modulated wave a (810 MH) distributed from the distributor 9 to the frequency converter 11 side.
z, −10 dBm) is converted to the intermediate frequency c (810 MHz) by the frequency conversion unit 11 by the high frequency signal e (800 MHz).
(z-800 MH = 10 MHz, -20 dBm). The power level conversion loss at this time is -1.
0 dB.

The intermediate frequency c is determined by the ALC circuit 13
The power level of the intermediate frequency c (−20 [dBm]) in the LOG-LINER amplifier unit 14 having a filter characteristic having a center frequency of 10 MHz and a band of 21 kHz.
Is converted to a DC voltage 15 (1.4 [V]) corresponding to
In the A / D converter, the DC voltage 15 (1.4
[V]) is converted to digital data 22 (1 Ch) corresponding to [V]).

The microprocessor (CPU) 18 converts the input digital data 22 into transmission output control signal data 23 previously stored in the ROM 17 (= the power level of the intermediate frequency c−the same as the corresponding digital data 22 of the DC voltage). By reading [1Ch], it is determined that the power level of the intermediate frequency c is -20 [dBm], that is, the power level of the modulated wave a is -10 [dBm], and the transmission output control signal 21 ( 028h), the transmission output control signal data 23 (1Ch) and the digital data 22 (1Ch) are constantly monitored and a comparison operation is performed so that they become the same, and the power level of the modulated wave a becomes -10 [dBm]. So that the control voltage data 19
(= Same as digital data 22 corresponding to the output power of variable gain amplifier 4) [28h] is generated and output.

The control voltage data 19 (28h) is D
The control voltage 26 (2
[V]) and supplied to the variable gain amplifier 4.

For example, when the output power of the variable gain amplifying unit 4 changes from -10 dBm to -9 dBm (increases) due to temperature fluctuation or the like, the power level of the intermediate frequency c (10 MHz) also increases from -20 dBm to -19 dBm. And
The DC voltage 15 also increases from 1.4V to 1.5V.

Since the digital data 22 (1Eh) converted by the first A / D converter 16 is different from the value (1Ch) of the transmission output control signal data 23 before fluctuation, the CPU 18 calculates The process is performed to change the control voltage data 19 from (28h) to (26h). That is, when the output power increases from -10 dBm to -9 dBm, the output voltage is converted to a control voltage 26 (2 V to 1.9 V) smaller than the previous value corresponding to the control voltage data 19. For this reason, the gain of the variable gain amplifying unit 4 is reduced, and the output power returns to the value before the change, that is, from -9 dBm to -10 dBm.

ALC control is performed as described above. This operation also independently controls other time slots (TS # 1 to TS # 5).

Next, when only carrier 2 is transmitted (TS
# 1).

High frequency signal b output from local oscillator 5
(820 MHz) is modulated by the modulator 6 to generate a modulated wave b (820 MHz). Next, the modulated wave b
Is output from the antenna 10 via the variable gain amplifying unit 7 for amplifying the gain according to the control voltage 27, the synthesizing unit 8, and the distribution unit 11. On the other hand, in the ALC control, the modulated wave b (820 MHz, -1) distributed from the distributor 9 to the frequency converter 11 side.
4 dBm) by the high frequency signal e (800 MHz)
Intermediate frequency d (820 MHz-800 MH = 20 MH)
z, −24 dBm). The conversion loss of the power level at this time is −10 dB.

The intermediate frequency d corresponds to the power level (−24 [dBm]) of the intermediate frequency d in the LOG-LINER amplifier 28 having a filter characteristic in which the center frequency of the ALC circuit 13 is 20 MHz and the band is 21 kHz. DC voltage 29 (1.2 [V])
DC voltage 15 in the A / D converter 30 of FIG.
(1.2 [V]) corresponding to the digital data 22 (18
h).

Thereafter, the flow of the signal of the carrier 2 includes the variable gain amplifier 7, the intermediate frequency d, the LOG-LINER amplifier 28, the DC voltage 29, the A / D converter 30, the digital data 31, the control voltage data 20, A / A converter 25 and control voltage 27 form an ALC control loop.

Finally, a case where carrier 1 and carrier 2 are transmitted simultaneously (TS # 5). As described above, the modulated wave a (810 MHz) and the carrier 2
At the same time is output.

Therefore, the modulated waves a and b are input to the frequency converter 11 at the same timing, and the intermediate frequencies c (10
Mhz) and d (20 Mhz), and the ALC circuit 1
3 is input. At this time, in the transmission path from the distribution unit 9 to the ALC circuit 13 via the frequency conversion unit 11, the modulated waves a and b or the intermediate frequencies c and d are multiplexed.

Therefore, the ALC circuit 13 to which the two intermediate frequencies c and d are input can process the intermediate frequency c in the loop of the carrier 1 and the intermediate frequency d in the loop of the carrier 2 at the same timing. Two ALCs
A control loop can be built.

Accordingly, ALC control in which the output power of the carrier 1 and the output power of the carrier 2 are different can be performed.

Next, another embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 8 is a diagram showing the configuration of the second embodiment of the present invention. In FIG. 8, first and second modulators 3, 6
And first and second variable gain amplifiers 4 and 7, respectively, are provided with frequency converters 33 and 34 for inputting the high frequency signal f from the local oscillator 32 and converting the frequency.
Further, the modulated waves c and d from the distribution unit 9 are
At the time of the frequency conversion, the high frequency signal f from the local oscillator 32 is input.

The transmission frequency of the multi-carrier transmitter 1 is
If the frequency is higher than the modulatable frequency of the modulators 3 and 6, there is a problem that direct modulation cannot be applied. This example is
The modulated waves c and d are transmitted to the local oscillator 32 in the frequency converter.
A high-frequency modulated wave can be output by performing frequency conversion with the high-frequency signal f from.

This embodiment has a new effect that frequencies exceeding the modulatable frequencies of the modulators 3 and 6 can be output.

As described above, according to the present invention, the following effects can be obtained.

The first effect of the present invention is that space saving of a circuit and low power consumption can be achieved.

The reason is that, in the present invention, the transmission line from the high-frequency signal to the intermediate frequency is shared, and the ALC control loop is shared.

The second effect of the present invention is that it enables ALC control with a wide dynamic range.

The reason is that, in the present invention, detection is performed by the LOG-LINER amplifier using the intermediate frequency.

A third effect of the present invention is that the cost is reduced when configuring a circuit.

The reason is that, in the present invention, when the output power is low, it is not necessary to use a zero-bias diode or to use an amplifier for driving a detection voltage.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an ALC circuit according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a control voltage and an output voltage in a variable gain amplifier.

FIG. 4 is a time chart of the operation status of the multi-carrier transmitter in one embodiment of the present invention.

FIG. 5 is a diagram showing input / output characteristics (power at intermediate frequency-output voltage) of a logarithmic / linear amplifier.

FIG. 6 shows a D / A of an ALC circuit according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an example of input data-output voltage of a converter.

FIG. 7 shows A / D of an ALC circuit according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an example of input voltage-output data of a converter.

FIG. 8 is a diagram showing a configuration of a second embodiment of the present invention.

FIG. 9 is a diagram illustrating a configuration of a conventional multicarrier transmitter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-carrier transmitter 2 1st local oscillator 3 1st modulator 4 1st variable gain amplifier 5 2nd local oscillator 6 2nd modulator 7 2nd variable gain amplifier 8 synthesizer 9 distribution Device 10 Antenna 11 Frequency converter 12 Third local oscillator 13 ALC circuit 14 First LOG-LINEAR amplifier 16 First A / D converter 17 ROM 18 CPU 21 Transmission control signal 24 First D / A converter 25 second D / A converter 28 second LOG-LINEAR amplifier unit 30 second A / D converter 32 fourth local oscillator 33 second frequency converter 34 third frequency converter 35 fifth Local oscillator 36 Sixth local oscillator

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[Procedure amendment]

[Submission date] December 25, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

According to the present invention, there is provided a TDMA (time division multiple access) type multi-carrier transmitter which achieves the above object.
vel Control; by sharing the automatic level control) loop is obtained by <br/> to reduce space, power consumption.

Claims (5)

[Claims] In a multi-carrier transmitter, each transmission line from gain amplification of a modulated wave by a different high-frequency signal to frequency conversion to obtain an intermediate frequency shares a loop for performing automatic level control. A multi-carrier transmitter characterized by the following. 2. The multicarrier transmitter according to claim 1, further comprising means for frequency-converting a plurality of modulated waves, detecting a power level of an intermediate frequency, and performing gain control of the modulated waves. 3. A first and a second modulated wave are generated by modulating first and second data with different first and second high-frequency signals output from the first and second local oscillators, respectively. First and second modulators, first and second variable gain amplifiers for amplifying the first and second modulation waves to variable gains, respectively, and first and second variable gain amplifiers. A combining unit that combines the two modulated waves output from the multiplexing unit, a distributing unit that distributes the output of the combining unit, and supplies one of the outputs to an antenna, and the other of the outputs distributed by the distributing unit as an input,
A frequency converter for frequency-converting the first and second modulated waves extracted for control to first and second intermediate frequencies with a third high-frequency signal from a third local oscillator, and a transmission output control signal And an ALC circuit for inputting the first and second intermediate frequencies and performing a comparison operation process, and outputting first and second control voltages to the variable gain amplifier. Multi-carrier transmitter characterized by keeping the output level constant. 4. The multi-carrier transmitter according to claim 3, wherein said ALC circuit detects the input intermediate frequency with a log-linear amplifier (LOG-LINEAR amplifier). 5. A second frequency converter for converting a high frequency signal from a third local oscillator as an input between said first and second modulators and said first and second variable gain amplifiers, respectively.
A third frequency conversion unit, wherein the first and second modulated waves from the distribution unit are transmitted to the third frequency conversion unit by the third frequency conversion unit.
4. The multicarrier transmitter according to claim 3, wherein the high frequency signal from the local oscillator is frequency-converted to an intermediate frequency.