JP2006279472A - Transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the power consumption of a transmitter which performs intermittent transmission (burst transmission) without disturbing communication of an adjacent channel. <P>SOLUTION: The transmitter starts ramp processing (302) in a period (start-up time 301 of a transmitting amplifier (amplification part)) wherein the gain 100 of the transmitting amplifier is unstable right after the transmitting amplifier beings to be supplied with electric power, and thus shorten the total start-up time 300 to shorten a period wherein the electric power is supplied to the transmitting amplifier. At this time, a ramp coefficient is calculated and generated while an influence of transient response of the transmitting amplifier is taken into consideration to realize ideal ramp characteristics, thereby suppressing the occurrence of an unnecessary frequency component of a transmitted signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for suppressing unnecessary frequency components of a transmission signal, for example, in a transmission apparatus that performs intermittent transmission.

In a transmission apparatus (burst transmission apparatus) that performs intermittent transmission, an unnecessary frequency component is generated due to a change in the envelope of the transmission signal at the start of signal transmission and at the end of transmission (frequency convolution phenomenon).
As means for solving this problem, conventionally, generation of unnecessary frequency components (ramp processing) has been performed by giving ideal ramp characteristics to changes in the envelope of a transmission signal.

As a technique for realizing the ramp processing, for example, there is Patent Literature 1.
FIG. 11 is a configuration diagram illustrating the burst transmission apparatus disclosed in Patent Document 1. In FIG.
This burst transmission apparatus includes a serial / parallel converter 832 that serial-parallel converts data input from a transmission data input unit 831, a ramp waveform storage memory 833 that stores rising and falling waveforms during burst communication, and a ramp waveform. A clock source 836 for generating a signal, a frequency division counter 837, a burst control unit 830, a normal transmission waveform data generation unit 838 for generating a waveform other than the ramp period, and a signal output from the ramp waveform storage memory 833 A selector 834 that is switched by a control signal from the burst control unit 830, a digital-analog converter 823 that converts waveform data output from the selector 834 into an analog signal, and a modulation signal output unit 835 are configured.
For example, in the rising and falling sections of the transmission burst signal, the waveform data of the transmission signal is stored in advance in the ramp waveform storage memory 833 with respect to the input signal, and the counter 837 is operated by the signal from the control unit 830 to The ramp waveform is read from the ramp waveform storage memory 833 according to the count value and output. The output signal is selected by the selector 834 based on the signal from the control unit 830, converted into an analog signal by the digital / analog converter 823, and output.
In a period other than rising and falling, the signal generated by the normal transmission waveform data generation unit 838 that performs waveform shaping processing on the input signal is selected by the selector 834 based on the signal from the control unit 830, and digitally selected. The analog signal is converted into an analog signal by the analog converter 823 and output.

Further, in the burst transmission apparatus, during a period in which transmission is not performed, power is not supplied to the transmission amplifier and power consumption is suppressed.
JP-A-5-153175

However, immediately after starting the supply of power to the transmission amplifier (transient response period), the gain of the transmission amplifier is not stable.
Therefore, conventionally, in order to avoid the influence of the transient response, it is necessary to extend the time for supplying power to the transmission amplifier back and forth with respect to the time for transmitting the burst signal, and the rise time and fall time become longer. There are challenges.
An object of the present invention is, for example, to solve the above-described problems, suppress generation of unnecessary frequency components of a transmission signal, and suppress power consumption of a transmission apparatus.

The transmission device according to the present invention is:
A conversion unit that converts an input signal into an output signal, and adjusts the amplitude of the output signal based on a predetermined control signal;
An amplification unit that amplifies the output signal converted by the conversion unit and outputs it as a transmission signal;
A control unit that generates, as the control signal, a signal for controlling the conversion unit so that a transmission signal output from the amplification unit falls within a predetermined frequency band even in a transient response period in which the gain of the amplification unit is unstable. When,
It is characterized by having.

  According to the present invention, even if a transmission signal is output without waiting for the transient response period to elapse, unnecessary frequency components can be suppressed, so that the power consumption of the transmission device can be reduced without interfering with the communication of adjacent channels. It has the effect of being suppressed.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

FIG. 1 is a diagram showing an example of the overall configuration of a burst transmission apparatus 200 (an example of a transmission apparatus) in this embodiment.
The modulation unit 220 (an example of a conversion unit) performs a ramp process. The modulation unit 220 includes a waveform generation filter 221 (an example of a waveform data generation unit) that shapes the transmission parallel data 402 (an example of an input signal), a multiplier 222 (an example of a multiplication unit) that performs ramp processing, and a digital signal. A digital-analog converter 223 (DAC) that converts the signal into an analog signal, a low-pass filter 224 (LPF) that removes harmonic components of the analog signal output from the digital-analog converter, and quadrature modulation of the I and Q baseband signals And a quadrature modulator 225 for generating a radio signal (an example of an output signal).
The transmission amplifier 250 (an example of an amplifying unit) amplifies the radio signal quadrature-modulated by the quadrature modulator 225 as a transmission signal 153 and outputs it from the antenna 260.
The burst control unit 230 (an example of a control unit) outputs a ramp coefficient 151 (an example of a control signal) during ON / OFF control of the transmission amplifier 250 and a ramp process.
The memory 240 stores the ramp coefficient.

  The burst control unit 230 may be configured by a CPU (Central Processing Unit) and a program stored in a nonvolatile memory such as a ROM. Or you may comprise by hardware. The same applies to other components.

  Next, the operation will be described.

The waveform generation filter 221 receives the transmission parallel data 402, generates a waveform of the input transmission parallel data 402, and outputs the waveform. That is, based on the transmission parallel data 402, a waveform (an example of waveform data) that is the basis of the transmission signal is generated and output. The waveform generated by the waveform generation filter 221 is output as digital data sampled at a predetermined frequency higher than the transmission clock frequency of the transmission parallel data 402.
For example, when the frequency band of the transmission signal is narrowly limited, the waveform generation filter 221 functions as a so-called Nyquist filter and prevents interference between symbols.

  The multiplier 222 multiplies the waveform output from the waveform generation filter 221 by the ramp coefficient 151 output from the burst control unit 230, adjusts the waveform amplitude, and generates compensated waveform data. When the ramp processing is not performed, the ramp coefficient 151 is 1, so the waveform output from the waveform generation filter 221 is output as it is.

  The digital / analog converter 223 performs digital / analog conversion on the compensation waveform data output from the multiplier 222 to obtain an actual output waveform.

  The low pass filter 224 removes harmonic components of the output waveform accompanying quantization.

The quadrature modulator 225 combines the signals from the two low-pass filters 224. The signal from the low-pass filter 224 has a carrier phase shift of 90 degrees, and becomes a quadrature modulation by combining the two signals.
The modulation method is not limited to quadrature modulation, and other modulation methods such as frequency modulation and phase modulation may be used.

  The transmission amplifier 250 amplifies the output signal output from the quadrature modulator 225 to a transmission level to obtain a transmission signal 153 and outputs it from the antenna 260.

In burst transmission, there are times when transmission is performed and times when transmission is not performed.
When transmission is started from a state in which nothing is transmitted (output zero), if transmission is performed at a maximum output at a stretch, the envelope of the transmission signal changes abruptly, and a frequency component associated therewith is generated (frequency Convolution phenomenon).
The same applies when the transmission is suddenly terminated from the transmission state at the maximum output.

When transmitting by dividing a narrow frequency band, if such a frequency component leaks to the adjacent channel, it becomes noise that interferes with the communication of the adjacent channel. Therefore, it is necessary to suppress the occurrence of such a leaky frequency component.
Further, such a leakage frequency component consumes useless power that does not contribute to signal transmission. Therefore, if the leakage frequency component is suppressed, the power consumption of the burst transmission apparatus 200 can be suppressed.

  Therefore, by gradually changing from the zero output state to the maximum output state (or vice versa), the occurrence of such leakage frequency components is suppressed. This is called ramp processing, and the change in output with respect to the time axis at this time is called ramp characteristics.

FIG. 2 is a diagram illustrating an example of an envelope of a transmission signal 153 output from the transmission amplifier at the start of transmission in the conventional example.
As shown in this figure, by gradually changing the amplitude of the transmission signal 153, the envelope 150 of the transmission signal is made a gentle curve to suppress the occurrence of leakage frequency components.

  The ideal lamp characteristic can be obtained by calculation using a predetermined function. This function is called a window function. A window function suitable for the purpose is selected in consideration of the allowable leakage frequency component size and rise time.

On the other hand, in a state where nothing is transmitted, power is not supplied to the transmission amplifier 250, thereby suppressing power consumption of the burst transmission apparatus 200 and supplying power to the transmission amplifier 250 only when transmission is performed.
Even when nothing is transmitted, the power supply may be suppressed by reducing the supplied voltage instead of cutting off the power.
The burst control unit 230 generates a transmission amplifier power control signal 152, and power is supplied to the transmission amplifier 250 only when power supply is instructed by the transmission amplifier power control signal 152.

However, the gain of the transmission amplifier 250 is usually not stable immediately after the start of power supply. Here, the period in which the gain of the transmission amplifier 250 is not stabilized is referred to as a transient response period.
In FIG. 2, the transmission amplifier 250 has a transmission amplifier gain 100 smaller than normal immediately after the start of power supply, and the transmission amplifier gain 100 is stabilized because of the rise time 301 of the transmission amplifier (transient response). After the period).
Conventionally, after the supply of power to the transmission amplifier 250 is started, the ramp process is started after the transient response period has passed and the gain is stabilized. Accordingly, the entire rise time 300 of the burst transmission apparatus 200 is the sum of the rise time 301 (transient response period) of the transmission amplifier 250 and the time 302 required for the ramp processing. It was.

FIG. 3 is a diagram showing an example of an envelope 150 of a transmission signal output from the transmission amplifier 250 at the start of transmission in this embodiment.
In this embodiment, as shown in FIG. 3, the overall rise time 300 is shortened by controlling the rise time 301 of the transmission amplifier and the ramp processing time 302 to overlap.

Therefore, the gain rising characteristic of the transmission amplifier 250 is measured in advance.
FIG. 4 is a diagram illustrating an example of a change in gain of the transmission amplifier 250 when power supply to the transmission amplifier 250 is started and when power supply is interrupted.
That is, as shown in FIG. 4, the gain 100 at the start of power supply of the transmission amplifier 250 is measured at a predetermined sampling period. In this example, data is measured at eight sampling points 101 to 108 during the rise time 301 of the transmission amplifier 250.
Apart from this, an ideal ramp coefficient is obtained in advance by calculation. That is, based on the selected window function, the size of the envelope 150 of the transmission signal at a predetermined time during the ramp process (ratio where the amplitude of the transmission signal during normal transmission is 1) is obtained.
Next, the ratio between the gain of the transmission amplifier measured at each sampling point 101 to 108 and the ideal ramp coefficient is obtained and stored in the memory 240 as the ramp coefficient.
FIG. 5 is a diagram showing an example of a lamp coefficient obtained by calculation from the measured gain 100 of the transmission amplifier and ideal lamp characteristics in this embodiment.

During the ramp processing, the burst control unit 230 reads out and outputs the ramp coefficient stored in the memory 240 (an example of a control signal).
Since the multiplier 222 multiplies the waveform data output from the waveform generation filter 221 by the ramp coefficient, the output signal output from the quadrature modulator 225 is a signal multiplied by the ramp coefficient compared to that during normal transmission.
For example, at the sampling point 101, the output signal output from the quadrature modulator 225 is 0.5 times that during normal transmission.
On the other hand, since the gain of the transmission amplifier 250 is 0.04 times that during normal transmission, the transmission signal actually output by the transmission amplifier 250 is 0.5 × 0.04 = 0.02 times, which is an ideal ramp. Equal to the coefficient.

  By repeating this processing in the ramp processing time, the envelope 150 of the transmission signal has an ideal ramp characteristic based on the selected window function.

Alternatively, the ramp coefficient may be obtained by the following method.
That is, the sampling points 101 to 108 are changed, and adjustment is performed so that the adjacent channel leakage power of the transmission signal output from the transmission amplifier 250 is minimized.
At this time, the sampling point of the ramp processing to be adjusted starts from a ramp coefficient calculated from an ideal window function in advance, and adjustment is performed from a point with a large amplitude that has a large amount affecting the adjacent channel leakage power.
That is, in the case of the rising ramp process, the adjustment is performed from the sampling point 108, and the adjustment is performed in the order of 107, 106, 105, 104, 103, 102, and 101.

  Depending on the characteristics of the transmission amplifier 250, when the transmission signal starts to be raised simultaneously with the start of power supply to the transmission amplifier 250 (190 in FIG. 3), an output larger than the gain of the transmission amplifier 250 may be required. . However, since an output exceeding the gain of the transmission amplifier 250 cannot be obtained, an ideal envelope cannot be obtained.

Therefore, in that case, it is necessary to start raising the transmission signal after a while from the start of power supply to the transmission amplifier (150 in FIG. 3).
However, this waiting time is smaller than waiting until the rise time 301 (transient response time) of the transmission amplifier has passed.
Therefore, the overall rise time 300 can be shortened.

In this way, the ramp coefficient is determined in such a manner as to compensate for the rising characteristic at the start of power supply of the transmission amplifier 250, and a signal having a magnitude multiplied by the ramp coefficient is input to the transmission amplifier 250, whereby ideal lamp characteristics are obtained. Can be obtained. As a result, leakage frequency components leaking to adjacent channels can be reduced, so that communication on other channels is not disturbed and power consumption can be suppressed.
Furthermore, since the ramp process can be started without waiting for the transient response period of the transmission amplifier 250 to elapse, the overall rise time can be shortened.

  Even when the power supplied to the transmission amplifier 250 is shut off at the end of transmission, the gain 100 of the transmission amplifier does not immediately become zero, but draws a constant falling curve, gradually decreases the output, and eventually becomes zero. (111 to 118 in FIG. 4).

  Therefore, as in the case of the power supply start described above, if the fall characteristic is measured in advance and the ramp coefficient is determined in consideration thereof, it is possible to wait for the end of the ramp process at the fall. Since the power supply to the transmission amplifier 250 can be cut off, the entire fall time can be shortened.

  Thereby, since the rise time and fall time of the whole burst transmission apparatus 200 can be shortened, the time for supplying power to the transmission amplifier 250 is shortened, and the power consumption of the entire burst transmission apparatus 200 can be suppressed.

  Further, since the ramp processing is performed by the multiplier 222, it is not necessary for the waveform generation filter 221 to generate a plurality of waveforms corresponding to the ramp coefficients. Thereby, the memory for storing the waveform can be reduced.

  As described above, this burst transmission apparatus includes a ramp processing circuit configured by a multiplier, and stores a ramp coefficient calculated or adjusted in advance so that adjacent channel leakage power is minimized at the output terminal of the transmission amplifier. And an optimum ramp coefficient stored in the memory in accordance with the transmission burst timing is output to the multiplier to perform the ramp processing.

  As described above, the ramp coefficient adjusted in advance to minimize the adjacent channel leakage power at the transmission amplifier output end is stored in the memory, and the ramp coefficient stored in the memory and the transmission signal are subjected to ramp processing by the multiplier. There is an effect of reducing adjacent channel leakage power at the output terminal of the transmission amplifier.

Embodiment 2. FIG.
The second embodiment will be described with reference to FIG.
FIG. 6 is a diagram showing an example of the overall configuration of burst transmission apparatus 200 (an example of a transmission apparatus) in this embodiment.
The burst transmission apparatus 200 includes a modulation unit 220 (an example of a conversion unit), a transmission amplifier 250 (an example of an amplification unit), an antenna 260, a burst control unit 230, a memory 240, and a temperature sensor 270 (a temperature measurement unit). An example).
Among these, the modulation unit 220, the transmission amplifier 250, and the antenna 260 are the same as those described in the first embodiment, and thus description thereof is omitted here.
The temperature sensor 270 measures the temperature of the transmission amplifier 250. Alternatively, the temperature inside the burst transmitter 200 may be measured.
As described in the first embodiment, the burst control unit 230 reads the ramp coefficient stored in advance in the memory 240 and performs ramp control.
Here, the memory 240 stores a plurality of sets of ramp coefficients corresponding to the temperature of the transmission amplifier 250 measured by the temperature sensor 270, and the burst control unit 230 stores the transmission amplifier 250 measured by the temperature sensor 270. The temperature is acquired and the corresponding ramp coefficient is read out.

The rising characteristic and falling characteristic of the transmission amplifier 250 may change depending on the temperature.
Therefore, an ideal lamp characteristic cannot be obtained by using a set of lamp coefficients regardless of the temperature of the transmission amplifier 250.

  Therefore, in this embodiment, the temperature sensor 270 measures the temperature of the transmission amplifier 250 and uses a lamp coefficient that matches the temperature of the transmission amplifier 250, thereby obtaining ideal lamp characteristics.

  That is, for each temperature range, the rising characteristics and the falling characteristics at the start of power supply of the transmission amplifier 250 and when the power supply is cut off are measured in advance, and the optimum ramp coefficient is obtained by calculation for each temperature range. The memory 240 stores in advance.

The temperature sensor 270 measures the temperature of the transmission amplifier 250 periodically (for example, at a cycle of 1 second).
The burst controller 230 reads the ramp coefficient corresponding to the temperature zone to which the temperature measured by the temperature sensor 270 belongs, from the memory 240, and outputs it to the multiplier 222 in accordance with the transmission burst timing.

  In this way, by performing temperature compensation for the lamp coefficient in consideration of temperature fluctuations in the apparatus, a transmission signal having ideal lamp characteristics can be obtained even when the transient response characteristic of the transmission amplifier 250 varies with temperature. Since it can output, adjacent channel leakage power can be reduced, communication of other channels is not disturbed, and power consumption of the burst transmitter 200 can be suppressed.

  As described above, this burst transmission device stores a ramp coefficient calculated or adjusted in advance so that the adjacent channel leakage power is minimized at the output terminal of the transmission amplifier for each temperature range within a certain temperature range. And an optimum ramp coefficient for each temperature detected by the temperature sensor is output to the multiplier.

  In this way, the ramp coefficient corresponding to each temperature zone is adjusted or calculated in advance, stored in the memory, the temperature inside the device is measured by the temperature sensor in the device, and the ramp coefficient of the temperature zone corresponding to this temperature is used. By performing the ramp processing, there is an effect of reducing the adjacent channel leakage power even when the transient response characteristic of the transmission amplifier varies with temperature.

Embodiment 3 FIG.
The third embodiment will be described with reference to FIGS.
FIG. 7 is a diagram showing an example of the overall configuration of burst transmission apparatus 200 (an example of a transmission apparatus) in this embodiment.
The burst transmission apparatus 200 includes a modulation unit 220 (an example of a conversion unit), a transmission amplifier 250 (an example of an amplification unit), an antenna 260, a burst control unit 230, a memory 240, and a temperature sensor 270 (a temperature measurement unit). An example) and a burst timing adjustment circuit 280.
Among these, the modulation unit 220, the transmission amplifier 250, the antenna 260, the burst control unit 230, the memory 240, and the temperature sensor 270 are the same as those described in the second embodiment, and thus description thereof is omitted here.
The burst timing adjustment circuit 280 adjusts the timing of power supply to the transmission amplifier 250 at the start and end of burst transmission.

As described in the first embodiment, depending on the transient response characteristics of the transmission amplifier 250, it may be necessary to shift the timing between the start of power supply to the transmission amplifier 250 and the rise of the transmission signal 153 (see FIG. 3).
Alternatively, it may be necessary to adjust the power supply timing of the transmission amplifier 250 in order to eliminate the influence of the delay time inside the apparatus.

In this embodiment, the timing of the signal for controlling the power supply of the transmission amplifier 250 generated by the burst control unit 230 is fixed, and the burst timing adjustment circuit 280 performs the above-described timing adjustment to transmit the transmission amplifier power control signal 152. Is generated.
However, a dedicated circuit for timing adjustment may not be provided, and the burst control unit 230 may perform such adjustment to generate the transmission amplifier power control signal 152 with adjusted timing.

Specifically, as shown in FIG. 7, a burst timing adjustment circuit 280 is added to the configuration shown in the second embodiment so that the transmission burst rise and fall times are minimized at the output terminal of the transmission amplifier 250. After adjusting the power control signal of the transmission amplifier, the ramp coefficient is adjusted or calculated so that the adjacent channel leakage power is minimized at the output terminal of the transmission amplifier 250, and this ramp coefficient is stored in the memory 240.
Then, as in the second embodiment, burst control section 230 reads the ramp coefficient from memory 240, and burst control section 230 outputs it to multiplier 222 in accordance with the transmission burst timing.

  As a result, a transmission signal having an ideal ramp characteristic can be output regardless of the transient response characteristic of the transmission amplifier and the delay time inside the apparatus, so that the rise time and fall time of the transmission burst signal can be minimized, and Since the adjacent channel leakage power can be reduced, the communication of the adjacent channel is not disturbed, and the power consumption of the burst transmitter can be suppressed.

  As described above, this burst transmission apparatus has a burst timing adjustment circuit that adjusts the on / off control signal of the transmission amplifier and a memory that stores the timing at which the rise and fall times of the transmission burst are optimal, and the burst timing adjustment The ramp coefficient calculated or adjusted in advance is stored in the memory so that the adjacent channel leakage power is minimized with respect to the burst transient response characteristic of the transmission amplifier adjusted by the circuit, and the memory is stored according to the transmission burst timing. The optimum ramp coefficient is output to the multiplier.

  As described above, the use of the circuit for adjusting the on / off timing of the transmission amplifier has an effect of minimizing the rise time and fall time of the transmission burst.

Embodiment 4 FIG.
The fourth embodiment will be described with reference to FIGS. 4 and 8 to 10.
FIG. 8 is a diagram showing an example of the overall configuration of burst transmission apparatus 200 (an example of a transmission apparatus) in this embodiment.
The burst transmission apparatus 200 includes a modulation unit 220 (an example of a conversion unit), a transmission amplifier 250 (an example of an amplification unit), an antenna 260, a burst control unit 230, a burst timing adjustment circuit 280, a distributor 291, It has a detector 292, an analog-digital converter 293 (ADC), and a ramp coefficient generation circuit 294.
Among them, the modulation unit 220, the transmission amplifier 250, the antenna 260, the burst control unit 230, and the burst timing adjustment circuit 280 are the same as those described in the third embodiment, and thus description thereof is omitted here.

The distributor 291 is a directional coupler that distributes the output of the transmission amplifier 250.
The detector 292 detects the envelope of the transmission signal distributed by the distributor 291.
The analog-digital converter 293 converts an analog signal into a digital signal.
The ramp coefficient generation circuit 294 automatically calculates the ramp coefficient 151 from the detected envelope of the transmission signal.

FIG. 9 is a detailed explanatory diagram showing an example of the internal configuration of the ramp coefficient generation circuit 294 in this embodiment.
The ramp coefficient adjustment unit 570 adjusts the ramp coefficient by integrating the envelope error of the transmission signal for each sampling point (101 to 108 and 111 to 118 in FIG. 4). In this example, there are 16 ramp coefficient adjustment units 570 (= the number of sampling points 101 to 108, 111 to 118), and each ramp coefficient adjustment unit 570 takes charge of the ramp coefficient at each sampling point.
In this example, the temperature of the transmission amplifier 250 is not taken into consideration. However, as described in the second embodiment, in the case where a different ramp coefficient is used for each temperature range in consideration of the temperature of the transmission amplifier 250. The ramp coefficient adjusting unit 570 may be provided by the number of sampling points × the number of temperature zones to be distinguished.
However, even if the temperature changes and the rising characteristics of the transmission amplifier change, the ramp coefficient changes due to feedback to compensate for this, so it is not necessary to distinguish the temperature range. This is preferable because the configuration of the transmission apparatus can be simplified.

The latch circuit 571 holds (stores) the envelope of the transmission signal converted into a digital signal by the analog-digital converter 293 in accordance with the sampling timing of the ramp processing.
The ideal envelope value storage unit 572 stores an ideal envelope value of the transmission signal (envelope ideal value) calculated based on ideal lamp characteristics.
The subtractor 573 subtracts the envelope ideal value stored by the envelope ideal value storage unit 572 from the envelope of the transmission signal stored by the latch circuit 571 to calculate an error from the envelope ideal value.
The weighting coefficient storage unit 575 stores a feedback coefficient (weighting coefficient) that reflects the envelope error in the ramp coefficient. Since the weighting coefficient represents the amount of feedback, it is a negative value. The larger the absolute value of the weighting coefficient, the faster the convergence, but if it is too large, it diverges (vibrates), so it is necessary to select an appropriate value.
The multiplier 574 multiplies the envelope error calculated by the subtractor 573 by the weighting coefficient stored in the weighting coefficient storage unit 575.
The latch circuit 579 stores the ramp coefficient at the sampling point that the ramp coefficient adjustment unit 570 is responsible for.
The adder 576 adds the output of the multiplier 574 to the ramp coefficient stored in the latch circuit 579 and integrates the error signal, thereby adjusting the ramp coefficient and calculating a new ramp coefficient.
The normal-time ramp coefficient storage unit 578 stores a ramp coefficient at a time other than the ramp processing interval.
The selector 577 switches the input ramp coefficient adjustment unit 570 according to the timing in the ramp processing, and selects and outputs the ramp coefficient.

  Next, the operation will be described.

First, in order to detect the envelope of the transmission signal, the distributor 291 distributes the transmission signal 153 output from the transmission amplifier 250.
The detector 292 detects the transmission signal distributed by the distributor 291 and detects the envelope 150 of the transmission signal.
The analog-digital converter 293 converts the envelope of the transmission signal detected by the detector 292 into a digital value.
The burst control unit 230 outputs a sampling signal that informs the sampling timing of the ramp processing that each ramp coefficient adjustment unit 570 is responsible for.
The latch circuit 571 holds (stores) the digital value output from the analog-digital converter 293 at the sampling timing of the ramp processing based on the sampling signal output from the burst control unit 230.
The subtractor 573 subtracts the envelope ideal value stored by the envelope ideal value storage unit 572 from the digital value of the envelope of the transmission signal held by the latch circuit 571 to obtain a difference, and an error (error signal) from the envelope ideal value. Is calculated.
The multiplier 574 multiplies the error signal calculated by the subtractor 573 by the weighting coefficient stored by the weighting coefficient storage unit 575 to calculate a feedback signal.
The latch circuit 579 stores the ramp coefficient at the sampling point that the ramp coefficient adjustment unit 570 is responsible for.
The adder 576 adjusts the ramp coefficient and calculates a new ramp coefficient by adding the feedback signal output from the multiplier 574 to the ramp coefficient stored in the latch circuit 579.
The latch circuit 579 stores the new ramp coefficient calculated by the adder 576 at the timing of the sampling point handled by the ramp coefficient adjustment unit 570.
Therefore, each time sampling is performed, the ramp coefficient stored in the latch circuit 579 is adjusted and approaches the ideal value.

  At each sampling point, the selector 577 switches the input to the ramp coefficient adjustment unit 570 in charge of the sampling point, and outputs the ramp coefficient adjusted by the ramp coefficient adjustment unit 570.

  As described in the first embodiment, the ramp coefficient output in this manner is input by the multiplier 222 and subjected to the ramp processing.

FIG. 10 is a diagram showing an example of the adjustment process of the ramp coefficient in this embodiment.
The ramp coefficient r (n) (n is a natural number) in this figure is stored in the latch circuit 579.
The ramp coefficient r (n) is stored for each sampling point by the latch circuit 579 of the ramp coefficient adjustment unit 570 in charge. Here, the ramp coefficient at the sampling point 105 (FIGS. 4 and 5) is taken as an example. I will explain it.

In the initial state, it is assumed that the latch circuit 579 stores 1 as the ramp coefficient r (1).
In addition, the weighting coefficient storage unit 575 stores −1 as the weighting coefficient m.

At the sampling point 105, since the transmission amplifier 250 is in the transient response period, the gain of the transmission amplifier 250 is 0.75 times the normal value. Therefore, the output transmission signal has an amplitude that is 0.75 times the normal value.
This is measured by a distributor 291, a detector 292, and an analog / digital converter 293. Since the latch circuit 571 stores this at the timing of the sampling point 105, the latch circuit 571 stores the measured value 0.75.
On the other hand, at the sampling point 105, the ideal ramp characteristic obtained from the selected window function is 0.50. This value is stored in the envelope ideal value storage unit 572.
Therefore, the error calculated by the subtractor 573 is 0.25.
Multiplier 574 multiplies this by weighting coefficient (−1) stored in weighting coefficient storage section 575 to calculate a feedback signal (−0.25).
The adder 576 calculates the ramp coefficient (0.75) to be used next time in addition to the ramp coefficient (1.00) stored in the latch circuit 579.
The latch circuit 579 stores the new ramp coefficient (0.75) calculated by the adder 576 and prepares for the next time.

  The same calculation is repeated at the start of the next burst transmission. The second time, transmission is performed using the ramp coefficient 0.75 obtained above, and as a result, a new ramp coefficient 0.688 is calculated and used as the next ramp coefficient.

  By repeating this, in this case, at the sixth time, the ramp coefficient stored in the latch circuit 579 becomes almost equal to the theoretical value (0.667), and ideal lamp characteristics can be obtained.

At the sampling point (101, 118, etc.) where the gain G of the transmission amplifier 250 is small, the influence of the ramp coefficient r on the output E is small. Therefore, the feedback is increased by increasing the absolute value of the weighting coefficient m. If so, convergence can be accelerated.
At this time, if the weighting coefficient is set so that the absolute value of the product of the gain G of the transmission amplifier 250 and the weighting coefficient m is 1 or less, the system will not diverge (vibrate).

As described above, when the ramp coefficient is automatically adjusted by feedback control, ideal lamp characteristics can be obtained without measuring the rising characteristics and falling characteristics of the transmission amplifier 250 in advance. Further, the memory 240 for storing the lamp characteristics calculated in advance is not necessary.
As a result, the adjacent channel leakage power can be reduced, so that the communication of the adjacent channel is not disturbed, and the power consumption of the burst transmitter 200 can be suppressed.

  Further, even at normal times other than the ramp processing time 302, the leakage frequency component leaking to the adjacent channel can be reduced if the ramp coefficient is not fixed to 1. This is because the window function at the normal time other than the rise time and the fall time may not be completely flat even if a substantially flat window function is selected.

  Therefore, in this embodiment, the normal-time ramp coefficient storage unit 578 stores the normal-time ramp coefficient, and the selector 577 selects and outputs the transmission signal to match the selected window function even at the normal time. Realize the envelope.

  In this way, even during normal times other than during ramp processing, the adjacent channel leakage power can be further reduced by controlling the ramp coefficient and making it ideal lamp characteristics, so that it does not interfere with adjacent channel communication. The power consumption of the burst transmission device 200 can be suppressed.

  As described above, this burst transmitter has a ramp processing circuit configured by a multiplier, has a directional coupler and a detector at the output end of the transmission amplifier, and an envelope of the detected transmission burst signal is an ideal window. The ramp coefficient is automatically updated so that the ramp characteristic by the function is obtained.

  In this manner, the adjacent channel leakage power at the transmission amplifier output end can be reduced by automatically updating the ramp coefficient so that the ramp characteristic at the transmission amplifier output end becomes an ideal characteristic using the window function. effective.

FIG. 3 is a diagram illustrating an example of an overall configuration of a burst transmission device 200 (an example of a transmission device) in the first embodiment. The figure which shows an example of the envelope of the transmission signal which a transmission amplifier outputs at the time of a transmission start in a prior art example. FIG. 3 is a diagram illustrating an example of an envelope 150 of a transmission signal output from a transmission amplifier 250 at the start of transmission in the first embodiment. The figure which shows an example of the change of the gain of the transmission amplifier 250 at the time of the electric power supply start to the transmission amplifier 250, and the time of interruption | blocking of electric power supply. FIG. 3 is a diagram illustrating an example of a lamp coefficient obtained by calculation from measured gain 100 of a transmission amplifier and ideal lamp characteristics in the first embodiment. FIG. 10 is a diagram illustrating an example of an overall configuration of a burst transmission apparatus 200 (an example of a transmission apparatus) in the second embodiment. FIG. 10 is a diagram illustrating an example of an overall configuration of a burst transmission apparatus 200 (an example of a transmission apparatus) in the third embodiment. FIG. 10 is a diagram illustrating an example of an overall configuration of a burst transmission apparatus 200 (an example of a transmission apparatus) in the fourth embodiment. FIG. 9 is a detailed explanatory diagram illustrating an example of an internal configuration of a ramp coefficient generation circuit 294 according to the fourth embodiment. In Embodiment 4, it is a figure which shows an example of the adjustment process of a ramp coefficient. The figure which shows an example of the burst transmitter in a prior art.

Explanation of symbols

  200 burst transmission device, 220 modulation unit, 221 waveform generation filter, 222 multiplier, 223 digital-analog converter, 224 low-pass filter, 225 quadrature modulator, 230 burst control unit, 240 memory, 250 transmission amplifier, 260 antenna, 270 temperature Sensor, 280 burst timing adjustment circuit, 291 distributor, 292 detector, 293 analog-digital converter, 294 ramp coefficient generation circuit, 570 ramp coefficient adjustment unit, 571 latch circuit, 572 envelope ideal value storage unit, 573 subtractor, 574 Multiplier, 575 Weighting coefficient storage unit, 576 adder, 578 selector, 578 normal time ramp coefficient storage unit, 579 latch circuit, 100 gain of transmission amplifier, 101-108, 111-118 sampling points , 150 Transmit signal envelope, 151 Ramp coefficient, 152 Transmit amplifier power control signal, 153 Transmit signal, 300 Burst transmission device rise time, 301 Transmit amplifier rise time, 302 Ramp processing time, 402 Transmit parallel data.

Claims (6)

A conversion unit that converts an input signal into an output signal, and adjusts the amplitude of the output signal based on a predetermined control signal;
An amplification unit that amplifies the output signal converted by the conversion unit and outputs it as a transmission signal;
A control unit that generates, as the control signal, a signal for controlling the conversion unit so that a transmission signal output from the amplification unit falls within a predetermined frequency band even in a transient response period in which the gain of the amplification unit is unstable. When,
A transmission device comprising: The control unit
The transmission device according to claim 1, wherein power supplied to the amplification unit is reduced when the amplification unit does not output a transmission signal. The control unit
The transmission device according to claim 1, wherein a control signal for controlling the conversion unit is generated so that an amplitude of the transmission signal has a predetermined lamp characteristic. The conversion unit is
A waveform data generator for generating waveform data corresponding to the input signal;
A multiplication unit that multiplies the waveform data generated by the waveform data generation unit by the control signal generated by the control unit, and calculates as compensation waveform data;
Digital-to-analog conversion of the compensation waveform data calculated by the multiplication unit to generate the output signal; and
The transmission apparatus according to claim 1, comprising: The transmission device further includes:
It has a temperature measurement unit that measures the temperature of the amplification unit,
The control unit
The transmission device according to claim 1, wherein the control signal is generated based on the temperature measured by the temperature measurement unit. The transmission device further includes:
A transmission signal measuring unit for measuring the transmission signal output by the amplifying unit;
The control unit
4. The transmission device according to claim 3, wherein the control signal is generated based on an error between the transmission signal measured by the transmission signal measuring unit and the predetermined lamp characteristic.

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