JPH10271079A - Method for demodulating modulation wave and demodulator for modulation wave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transmission efficiency by decreasing a convergence time of a control variable for amplitude gain control and synchronization detection control to an optimum value different from each input modulation wave from each transmitter more than that of a conventional method in the case of demodulating a modulation wave so as to reduce a preamble period. SOLUTION: A VOC control voltage storage section 41a and an AGC control voltage storage section 41b store converged values of control values in each control and in the case of demodulating data from a same transmitter next, pre-processing is conducted to control each control variable to the stored converged value in advance and then substantial control is conducted after that. That is, the control values are approached to values closer to the optimum control values before the arrival of a modulation wave being an object of demodulation through the execution of the pre-processing, and then substantial control of converging AGC and VOC control voltages in the state so as to allow the control values to reach optimum values in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modulated wave demodulating method for receiving modulated waves from a plurality of transmitters by time division multiple access (TDMA) using the same channel and demodulating the received modulated waves, and the method. The present invention relates to a modulated wave demodulation device using the same.

[0002]

2. Description of the Related Art Conventionally, when digital data is transmitted over a CATV network or the like as a transmission path, QPSK
(Quadrature Phase Shift Keying), QAM (Quadrat
ure Amplitude Moduration), VSB (Vestigal Side)
Digital modulation transmitter / receiver using Band) modulation or the like is employed. On the receiver side for demodulating a signal modulated by the above-described modulation method, a voltage-controlled oscillator (VC
O) and an automatic gain control (AGC) unit exist as components of the demodulation device. The control of the VCO and the AGC unit is usually performed with an analog voltage, and the control is started as soon as the modulated wave is input to the receiver. When the control wave reaches the optimum control voltage, normal demodulation is performed and data is output.

However, the optimum values of these control voltages are not determined at the moment when the modulated wave is input, but the determination of whether the control voltage is up or down at regular intervals is repeated and gradually converged to the optimum value. Go. For this reason, the time required for the above-described processing is always required from the time when the modulated wave is input to the time when normal data can be output, and during this period, information cannot be carried as a payload. Therefore,
During this period, the transmitter outputs preamble data for establishing the demodulation operation.

[0004]

Therefore, in a situation where a modulated wave from a certain transmitter is always being received, the temporal loss due to the preamble period can be ignored, but a plurality of transmitters cannot transmit the modulated wave. In the case where the method of receiving the modulated wave of (1) by time division multiple access (TDMA) using the same channel is adopted, the time loss due to the preamble period greatly affects the overall transmission efficiency.

The effect will be described. FIG. 4 (a)
Indicates a data format in the TDMA system. Here, it is assumed that modulated waves from three transmitters A, B and C repeatedly use the same channel.
The cycle is 1 TDMA frame (hereinafter simply referred to as “frame”)
, And each transmitter transmits a modulated wave in a predetermined time slot for a predetermined time. The data carried on the modulated wave is called slot data. Further, a predetermined guard time Tg is provided between slot data in order to prevent interference so that modulated waves do not overlap each other.
The slot data Ds transmitted from each transmitter is composed of valid data (data A, B, and C) to be transmitted and the above-described preamble data Dp. Although the preamble data Dp is indispensable for normal demodulation on the receiver side, it is not valid data to be transmitted originally, so that the data transmission efficiency is reduced. That is,
The time other than the time required for transmitting valid data is considerably increased, and the number of transmitters capable of transmitting data within a predetermined time is reduced, leading to a reduction in access response and the like.

In order to reduce the time loss due to the preamble data Dp, the time slot allocated to each transmitter may be set to be long. In this case, however, there is a disadvantage that the memory amount and the delay amount of each transmitter increase. is there. As another method, the preamble period itself can be reduced. However, if the preamble period is simply reduced, data is discharged in a state where the receiving operation is unstable. Therefore, in the control of the VCO and the AGC section described above, it is necessary to set the maximum time that can be assumed until the optimum control voltage is reached. In other words, it must be set to be equal to or longer than the time required to reach the appropriate value from the predetermined initial value.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and control values for amplitude gain control and synchronous detection control converge to optimal values that differ for each input modulated wave from each transmitter. It is an object of the present invention to provide a modulation wave demodulation method and a modulation wave demodulation device using the method, in which the preamble period is reduced and the transmission efficiency is improved by shortening the time required to perform the method. .

[0008]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a method for transmitting modulated waves from a plurality of transmitters by time division multiple access using the same channel. Received, the amplitude modulation control according to the value of the gain control signal is performed on the received modulation wave to make the amplitude-controlled modulation wave, in the modulation wave demodulation method for demodulating the amplitude-controlled modulation wave, the plurality of When a demodulation operation is performed on a modulated wave from one of the transmitters, a gain control signal value at the time of completion of the amplitude gain control is stored, and then a signal from the same transmitter is stored. When demodulating the modulated wave, a gain control pre-process for performing amplitude gain control using the stored gain control signal value is performed before performing the original amplitude gain control. .

According to a second aspect of the present invention, a modulated wave from a plurality of transmitters is received by time division multiple access using the same channel, and the received modulated wave is converted into a synchronous detection control signal value. In the modulation wave demodulation method of performing a synchronous detection control in accordance with the modulated wave and demodulating the modulated wave, when a demodulation operation is performed on a modulated wave from one of the plurality of transmitters, the synchronous detection control is performed. The value of the control signal for synchronous detection at the time of completion of the above is stored, and when demodulating a modulated wave from the same transmitter next time, the value is stored before performing the original synchronous detection control. A synchronous detection pre-process for performing synchronous detection control using the synchronized detection control signal value is performed.

Further, according to the present invention, a modulated wave from a plurality of transmitters is received by time division multiple access using the same channel, and the received modulated wave is adjusted according to a value of a gain control signal. In the modulation wave demodulation method for performing amplitude gain control and performing amplitude control on a modulated wave, performing synchronous detection control according to the value of the synchronous detection control signal on the amplitude-controlled modulated wave, and demodulating the modulated wave, When performing a demodulation operation on a modulated wave from one of the plurality of transmitters, a gain control signal value at the time of completion of the amplitude gain control and a synchronous detection at the time of completion of the synchronous detection control. The value of the control signal is stored in advance, and when demodulating a modulated wave from the same transmitter next time, the stored gain control signal value is used before performing the original amplitude gain control. For gain control using amplitude gain control Processing with performing, before the original synchronous detection control, and performs the preprocessing for synchronous detection which performs synchronous detection control using the stored that had been synchronous detection control signal value.

Each of these modulation wave demodulation methods is a method of receiving modulation waves from a plurality of transmitters by time division multiple access using the same channel and demodulating the received modulation waves. In the case of (2), it is assumed that amplitude gain control according to the value of the gain control signal is performed on at least the received modulated wave. In the case of claim 2, at least the received modulated wave is used for synchronous detection. It is assumed that synchronous detection control according to the value of the control signal is performed. The case of claim 3 is based on the premise that both of them, that is, the amplitude gain control is performed, and the synchronous detection control is performed on the modulated wave whose amplitude is controlled.

When a demodulation operation is performed on a modulated wave from a transmitter among a plurality of transmitters, a gain control signal value upon completion of amplitude gain control and a gain control signal upon completion of synchronous detection control are obtained. The value of the control signal for synchronous detection is stored, and when demodulating a modulated wave from the same transmitter next time, the gain control signal value stored before performing the original amplitude gain control is stored. Perform pre-processing for gain control that performs amplitude gain control using, or perform synchronous detection control using the stored control signal value for synchronous detection before performing the original synchronous detection control. Pre-processing is performed.

As described in the description of the prior art, the optimum values of these control signals are not determined at the moment when the modulated wave is inputted, but the determination of the control value up and down performed at regular intervals is repeated. Gradually converge to the optimal value. For this reason, the time required for the above-described processing is always required from the time when the modulated wave is input to the time when normal data can be output, and during this period, information cannot be carried as a payload. Therefore, time division multiple access (TDMA) using modulated waves from a plurality of transmitters using the same channel
In the case of adopting the method of receiving data, the time loss due to the preamble period greatly affects the overall transmission efficiency.

According to the modulated wave demodulation method of the present invention, the preamble period can be shortened as compared with the prior art. The reason will be described in comparison with the conventional method. First, in the case of the conventional method, it is necessary to set, as the preamble period, the maximum time that can be assumed until the control value of the amplitude gain control or the synchronous detection control reaches the optimum control value, and a predetermined initial time is required. It had to be set longer than the time required to reach the appropriate value from the value. On the other hand, in the case of the present invention, the previous control value is stored, and pre-processing is performed using the stored control value before executing the original control. Therefore, before the modulated wave to be demodulated arrives, it can be brought close to a value close to the optimal value of the control value, and if the original amplitude gain control or synchronous detection control is performed from that state, it can be performed in a relatively short time. The control value will reach the optimum value. As a result, the preamble time can be set short, and the transmission efficiency can be improved.

The following configuration is conceivable as a modulated wave demodulator using the above method. For example, the modulated wave demodulation device according to claim 4 is a receiving unit that receives modulated waves from a plurality of transmitters by time division multiple access using the same channel, and a value of a gain control signal for the received modulated wave. And a demodulator for demodulating the modulated wave whose amplitude is controlled by the amplifier. When performing a demodulation operation on a modulated wave from a transmitter in a device, storage means for storing a gain control signal value at the time of completion of amplitude gain control in the amplifying means, When demodulating a modulated wave from the same transmitter, a gain control unit for performing amplitude gain control using the gain control signal value stored in the storage unit before performing the original amplitude gain control. Preprocessing,
And an amplification control unit executed by the amplification unit.

Further, the modulated wave demodulation device according to claim 5 is
Receiving means for receiving modulated waves from a plurality of transmitters by time-division multiple access using the same channel; and performing synchronous detection control on the received modulated waves according to the value of a synchronous detection control signal. And a demodulation means for demodulating the signal. When a demodulation operation is performed on a modulation wave from a certain one of the plurality of transmitters, a synchronous detection control by the demodulation means is performed. Storage means for recording the value of the control signal for synchronous detection at the time of completion, and when demodulating a modulated wave from the same transmitter next, before performing the original synchronous detection control, It is characterized in that the demodulation means includes demodulation control means for causing the demodulation means to execute synchronous detection preprocessing for performing synchronous detection control using the stored synchronous detection control signal value.

Further, a modulated wave demodulating apparatus according to claim 6 is a receiving means for receiving modulated waves from a plurality of transmitters by time division multiple access using the same channel, and a gain for the received modulated wave. Amplifying means for performing amplitude gain control according to the value of the control signal to obtain a modulated wave whose amplitude is controlled, and synchronous detection control according to the value of a synchronous detection control signal for the modulated wave whose amplitude is controlled by the amplifying means. Do
And a demodulating means for demodulating the modulated wave. When a demodulation operation is performed on a modulated wave from a certain transmitter among the plurality of transmitters, an amplitude gain in the amplifying means is obtained. Storage means for recording the gain control signal value at the time of completion of the control and the value of the synchronous detection control signal at the time of the completion of the synchronous detection control by the demodulation means; and a modulated wave from the same transmitter. At the time of demodulation, before performing the original amplitude gain control, a gain control pre-process for performing amplitude gain control using the gain control signal value stored in the storage means is performed on the amplification means. Amplification / demodulation that causes the demodulation means to execute synchronous detection pre-processing for performing synchronous detection control using the stored synchronous detection control signal value before performing the original synchronous detection control. Control means.

The functions exhibited by these modulated wave demodulators
The effects are basically the same as those described as the modulation wave demodulation method, and thus will not be repeated here. Conventionally, the amplitude gain control is often performed using an automatic gain control (AGC) unit, and the synchronous detection control is often performed using a voltage controlled oscillator (VCO). The control of the VCO is usually performed by an analog voltage. Therefore, in this case, the gain control signal value and the synchronous detection control signal value are stored as voltage control values.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a modulated wave demodulation device 40 as one embodiment. The modulated wave demodulator 40 selects one desired channel from the frequency-multiplexed modulated waves, and selects an intermediate frequency (IF).
, And a surface acoustic wave (SAW) filter 22 for limiting a modulated wave from the tuner 21 to a desired frequency band.
And an amplifier 23 as amplifying means for amplifying the modulated wave band-limited by the SAW filter 22 to an optimal level for demodulation, and a demodulator 24 as a demodulating means for demodulating the modulated wave amplified by the amplifier 23. A data determiner 25 for reproducing a baseband signal demodulated by the demodulator 24 into a digital data signal; and a voltage controlled oscillator (VCO) for generating a voltage required for synchronous detection in the demodulator 24. In addition to having the respective configurations that existed in the conventional device of 26,
As a further characteristic configuration, the VCO control voltage storage unit 41
a and an AGC control voltage storage unit 41b. The configurations of the VCO control voltage storage unit 41a and the AGC control voltage storage unit 41b will be described later in detail.

The data decision unit 25 corresponds to amplification / demodulation control means, and outputs a VCO control signal and an AGC control signal. The VCO control signal gives an analog control voltage to the VCO 26. On the other hand, the AGC control signal supplies an analog control voltage which is at an optimum level for demodulation to the amplifier 23.
To supply. That is, the amplifier 23 has AGC, that is, an automatic gain control function, and performs AGC based on the AGC control signal.

The above-described control loop after the amplifier 23 starts operating toward an optimum control voltage as soon as a desired modulated wave is selected by the tuner 21, and after converging to an optimum value, the data judgment unit 25 Is output. This control loop is performed not only when another modulated wave is selected by the tuner 21 but also for each slot data from each transmitter using the same channel in the TDMA system. (= Preamble period) was important in improving transmission efficiency.

In order to shorten the convergence time (= preamble period) of the control loop, in the present embodiment, the VCO control signal and the AGC control signal from the data decision unit 25 which have conventionally existed in the middle of the supply path. Then, a modulation wave demodulation device 40 in which a VCO control voltage storage unit 41a and an AGC control voltage storage unit 41b are newly provided was invented.

Next, a specific configuration of the VCO control voltage storage section 41a and the AGC control voltage storage section 41b corresponding to storage means will be described with reference to the block diagram of FIG. The VCO control voltage storage unit 41a and the AGC control voltage storage unit 41b have the same basic configuration, and differ only in the type and output destination of the input and output control voltages. As long as the storage unit 41
Both are indicated as a and 41b.

As shown in FIG. 2, the storage units 41a and 41b
Is an A / D converter 51, a CPU 52, a memory 53
, A D / A converter 54, and an input switch 55. From the data decision unit 25, the VCO control voltage or AG
The C control voltage is stored in the storage unit 41a as an analog control signal.
Input to 41b. The input VCO control voltage or AGC control voltage is supplied to the A / D converter 51 and the input switch 55. The A / D converter 51 converts the analog value into a digital value, sends the digital value to the CPU 52, and stores the digital value in the memory 53. In the memory 53, a storage area is prepared for each transmitter, and each time the storage area is demodulated with a modulated wave from the transmitter, the storage area is updated and stored to the optimal value of the control voltage finally converged at that time. Go.

The value stored in the memory 53 is stored in the CPU 5
2 to the D / A converter 54 and supplied to the input switch 55 as an analog value. The input switch 55 receives the VCO control voltage or AGC input from the data
The input is switched to the control voltage as it is or the output signal from the D / A converter 54, whichever is in accordance with the instruction of the CPU 52, and the input is switched to the VCO 26 or the amplifier 23 as the control voltage output. Will be supplied. The input switching in the input switch 55 is performed by the CPU 52, and a control voltage based on the data stored in the memory 53 is supplied during the guard time Tg after receiving the slot data from a certain transmitter. Therefore, control is performed so that the control voltage from the D / A converter 54 is output. Then, at the timing when the guard time Tg ends, the VCO control voltage or the AG
The input switch 55 is controlled so that the C control voltage is output.

The control for supplying the AGC control voltage based on the data stored in the memory 53 during the guard time Tg corresponds to the “gain control pre-processing”, and the memory 53 also performs the control during the guard time Tg. The control for supplying the VCO control voltage based on the data stored in the "Synchronous detection" corresponds to "preprocessing for synchronous detection". By performing these controls, it is possible to bring the control voltage of the VCO 26 and the amplifier 23 within the guard time Tg closer to the optimum value in advance to normally receive and demodulate the slot data to be demodulated normally. It becomes.

This point is compared with the time chart of FIG.
This will be further described with reference to the data format of the TDMA system in (b). FIG. 3 shows a state from the first frame to the third frame. The case of the second and third frames corresponds to FIG. 4B.

As shown in FIG. 4B, it is assumed here that the same channel is repeatedly used by the modulated waves from the three transmitters A, B and C. Transmits a modulated wave in a predetermined time slot for a predetermined time. A predetermined guard time Tg is provided between the slot data Ds carried on the modulated wave so as to prevent interference between the modulated waves so as not to overlap each other. The slot data Ds transmitted from each transmitter is
It consists of valid data to be transmitted (data A, B, C) and preamble data Dp.

The period in which the preamble data Dp exists is defined as a preamble period Tp * or tp * (* = a, b, c
Any of them). In FIG. 3, since “gain control pre-processing” or “synchronous detection pre-processing” is performed in the second and third frames, the preamble period is represented as tp *, and only the first frame is controlled by these control methods. Is not performed, the preamble period is represented as Tp *. Note that the guard time Tg has the same length in each case.

In FIG. 3, preamble periods TPA, TPB, and
The TPC operates so that the optimum control values VA1, VBA and VCA according to each slot data Ds are obtained. At this time, the preamble period TPA is determined in consideration of the time required to converge to the optimum control value VA1 from the initial level because the control returns to the initial level within the guard time Tg every time. The preamble period TPB is determined in consideration of the time required for convergence to VB1, and the preamble period TPC is determined in consideration of the time required for convergence from the initial level to the optimum control value VC1.

On the other hand, the control is different from the second frame onward. First, a demodulation process is performed with the last slot data of the first frame converged to the optimum control value VC1, and then a guard time Tg between the last slot data and the first slot data of the second frame (see FIG. 3). Within
The above-described preprocessing (gain control preprocessing or synchronous detection preprocessing) is performed. The pre-processing is the last time, that is, in this case, the optimum control value V for the data A of the first frame.
This is the process of converging to A1. That is, in this case, the process of converging from the state of the optimum control value VC1 for the data C of the first frame to the optimum control value VA1 for the data A of the first frame is executed in the guard time Tg (in FIG. 3). .

In the original preamble period tPA for the data A of the second frame, the second control value VA1 for the data A of the first frame is used as a reference.
The control for converging to the optimal control value VA2 for the frame data A is performed. Although the optimum control value VA2 for the data A in the second frame is slightly larger than the optimum control value VA1 in the first frame, the time required to converge by starting from the initial level as in the first frame. It is considerably shortened compared to.

Similarly, within the guard time Tg (see FIG. 3) between the first slot data (data A) and the next slot data (data B) of the second frame,
As preprocessing, a process of converging to the optimum control value VB1 for the data B of the first frame is executed. In this case, the state of the optimum control value VA2 for the data A of the second frame is changed from the state of the optimum control value V2 for the data B of the first frame.
The process of converging to B1 is executed during this guard time Tg (in FIG. 3). Then, in the original preamble period tPB for the data B of the second frame, the optimal control value VB2 for the data B of the second frame is set based on the optimal control value VB1 for the data B of the first frame obtained by the preprocessing. Control to converge is performed. The optimum control value VB2 for the data B of the second frame is
Although slightly increased from the optimal control value VB1 in the first frame, it is considerably reduced compared to the time required to start from the initial level and converge as in the first frame.

In each of the subsequent guard times Tg,
Since the same preprocessing is performed, the subsequent original preamble period tP * is considerably shorter than the preamble period TP * in the first frame in which no preprocessing is performed. In other words, by performing the preprocessing described above, it is possible to bring the control value closer to the optimal value of the control value before the modulated wave to be demodulated arrives, and to perform the original amplitude gain control and the synchronous detection control from that state. If performed, the control value reaches the optimum value in a relatively short time.

Therefore, in the present embodiment, as shown in FIG. 4B, by performing preprocessing, the preamble period t
PA, tPB, and tPC do not perform preprocessing respectively.
The conventional preamble periods TPA, TPB, TPC shown in FIG.
There is no problem if the setting is shorter than this, and the frame length can be shortened. As a result, valid data A, B,
The transmission amount of C can be increased, and the transmission efficiency can be improved.

The modulated wave demodulator 40 of this embodiment has a configuration in which a VCO control voltage storage unit 41a and an AGC control voltage storage unit 41b are added to the basic configuration of the conventional device. Generally, the CPU 52 and the memory 53 (see FIG. 2) in the storage units 41a and 41b are already incorporated in a receiving device or the like in which the present modulated wave demodulation device 40 is incorporated. In that case, FIG. It is only necessary to add the A / D converter 51, the D / A converter 54, and the input switch 55 as shown, which is advantageous in terms of cost.

As described above, the present invention is not limited to such an embodiment, and can be implemented in various forms without departing from the gist of the present invention. For example, in the above-described embodiment, the “gain control preprocessing”, which is a control for supplying an AGC control voltage based on the data stored in the memory 53, within the guard time Tg, and the guard time Tg
Within the V based on the data stored in the memory 53.
The pre-processing for synchronous detection, which is the control for supplying the CO control voltage, is performed together. However, the shortening of the preamble period can be realized by only one of the controls.
However, it is generally considered that the time required for the AGC to converge to the optimum value is longer in the case of AGC. Therefore, if any one of the methods is used, it is more effective to execute the “gain control preprocessing”. Seem.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a modulated wave demodulation device as an embodiment.

FIG. 2 shows a VCO control voltage storage unit and an AGC according to the embodiment.
FIG. 3 is a block diagram illustrating a schematic configuration of a control voltage storage unit.

FIG. 3 is a time chart illustrating an operation of pre-processing by the modulated wave demodulation device of the embodiment.

FIGS. 4A and 4B are diagrams illustrating a data format of a TDMA system, in which FIG. 4A is a diagram illustrating a conventional case, and FIG.

[Explanation of symbols]

 Reference Signs List 21 tuner 22 SAW filter 23 amplifier 24 demodulator 25 data determiner 40 modulated wave demodulator 41a VCO control voltage storage unit 41b AGC control voltage storage unit 51 A / D converter 53 memory 54 ... D / A converter 55 ... Input selector

Claims (7)

[Claims] 1. A modulation wave from a plurality of transmitters is received by time division multiple access using the same channel, and amplitude modulation control is performed on the received modulation wave in accordance with a value of a gain control signal to perform amplitude control. In a modulation wave demodulation method for demodulating a modulated wave whose amplitude is controlled, a demodulation operation is performed on a modulated wave from a certain transmitter among the plurality of transmitters. The gain control signal value at the time of the completion of the gain control is stored, and when demodulating a modulated wave from the same transmitter next time, the gain control signal value is stored before performing the original amplitude gain control. A modulated wave demodulation method characterized by performing gain control preprocessing for performing amplitude gain control using a gain control signal value. 2. Modulation waves from a plurality of transmitters are received by time division multiple access using the same channel, and the received modulation waves are subjected to synchronous detection control according to the value of a synchronous detection control signal, and modulated. In a modulated wave demodulation method for demodulating a wave, when a demodulation operation is performed on a modulated wave from a transmitter among the plurality of transmitters, a control signal for synchronous detection upon completion of the synchronous detection control When demodulating a modulated wave from the same transmitter next time, before executing the original synchronous detection control, the stored synchronous detection control signal value is used. And performing a synchronous detection pre-process for performing synchronous detection control. 3. A modulated wave from a plurality of transmitters is received by time division multiple access using the same channel, and amplitude modulation is performed on the received modulated wave according to a value of a gain control signal to perform amplitude control. In the modulated wave demodulation method of performing synchronous detection control according to the value of the synchronous detection control signal on the modulated wave whose amplitude has been controlled, and demodulating the modulated wave, one of the plurality of transmitters When a demodulation operation is performed on the modulated wave from the transmitter, a gain control signal value at the time of completion of the amplitude gain control and a value of a synchronous detection control signal at the time of completion of the synchronous detection control are stored. Next, when demodulating a modulated wave from the same transmitter, before performing the original amplitude gain control, the gain control for performing the amplitude gain control using the stored gain control signal value is performed. Perform pre-processing and Modulated wave demodulation method before performing detection control, and performs the preprocessing for synchronous detection which performs synchronous detection control using the stored that had been synchronous detection control signal value. 4. A receiving means for receiving modulated waves from a plurality of transmitters by time division multiple access using the same channel, and performing amplitude gain control according to a value of a gain control signal for the received modulated waves. And a demodulating means for demodulating the modulated wave whose amplitude has been controlled by the amplifying means. The modulated wave demodulating device comprising: a transmitter among the plurality of transmitters; When a demodulation operation is performed on the modulated wave from the storage unit, a storage unit that stores a gain control signal value at the time of completion of the amplitude gain control in the amplification unit; When demodulating a wave, before performing the original amplitude gain control, a gain control pre-process for performing amplitude gain control using the gain control signal value stored in the storage means is performed by the amplification means. Amplification control hand to be executed When the modulation wave demodulation apparatus and performing comprise a. 5. A receiving means for receiving modulated waves from a plurality of transmitters by time division multiple access using the same channel; and synchronous detection control for the received modulated waves according to a value of a synchronous detection control signal. And a demodulating means for demodulating the modulated wave. In a modulated wave demodulating device comprising: a demodulating means for performing a demodulating operation on a modulated wave from a transmitter among the plurality of transmitters. Storage means for recording the value of the control signal for synchronous detection at the time of completion of synchronous detection control in the above, and the original synchronous detection control is performed when demodulating a modulated wave from the same transmitter next time And demodulation control means for causing the demodulation means to execute synchronous detection pre-processing for performing synchronous detection control using the stored synchronous detection control signal value. Modulated wave demodulator. 6. A receiving means for receiving modulated waves from a plurality of transmitters by time division multiple access using the same channel, and performing an amplitude gain control on the received modulated waves according to a value of a gain control signal. Amplifying means for performing an amplitude-controlled modulated wave; demodulating means for performing synchronous detection control according to the value of a synchronous detection control signal on the modulated wave whose amplitude is controlled by the amplifying means, and demodulating the modulated wave; In the modulated wave demodulation device comprising: when performing a demodulation operation on a modulated wave from a certain one of the plurality of transmitters, the gain control at the time of completion of the amplitude gain control in the amplifying means Storage means for recording a signal value and a value of a synchronous detection control signal at the time of completion of synchronous detection control by the demodulation means; and when demodulating a modulated wave from the same transmitter, Before performing amplitude gain control A gain control pre-process for performing amplitude gain control using the gain control signal value stored in the storage means, while causing the amplification means to execute,
Amplification / demodulation control means for causing the demodulation means to execute preprocessing for synchronous detection for performing synchronous detection control using the stored synchronous detection control signal value before performing the original synchronous detection control, A modulated wave demodulation device, comprising: 7. The modulated wave demodulator according to claim 6, wherein the gain control signal value and the synchronous detection control signal value are voltage control values.