JPH0522185B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse transmitter used in radar devices, wireless communication devices, etc.

[Conventional technology]

FIG. 5 is a system diagram showing the general configuration of a conventional transmitting device that transmits a plurality of pulse trains at each transmission repetition period. This figure shows an example in which the number of sub-pulses constituting a pulse train is two, and shows a case where the transmission frequency of each sub-pulse can be set separately. In the figure, 1 and 2 are oscillators, 3 and 4 are pulse modulators, 5 is a timing generator, 6 is a power combiner, 7 is an element such as a phase shifter or variable attenuator controlled for each sub-pulse, and 8 is the final stage class C amplifier.

Next, the operation will be explained with reference to the system diagram in FIG. 5 and the timing chart in FIG. 6. The output of oscillator 1 with frequency f _A is output from timing generator 5
Pulse modulator 3 by the modulated pulse V _A created by
The sub-pulse P _A is modulated by Similarly, the output of the oscillator 2 having a frequency f _B is modulated by the pulse modulator 4 using the modulation pulse V _B generated by the timing generator 5, and becomes a sub-pulse P _B. These sub-pulses P _A and _PB are combined by a power combiner 6 to form a transmission pulse _PT . Next, the transmission pulse P _T is subjected to phase correction or level correction for each sub-pulse by an element 7 such as a phase shifter or a variable attenuator that is controlled for each sub-pulse, and then amplified by a class C amplifier 8 and output. At this time, since the phase shifter or variable attenuator 7 is controlled for each sub-pulse, it is necessary to provide a gap ΔT that is sufficiently larger than the response time between the sub-pulses P _A and P _B.

[Problems to be Solved by the Invention] Conventional pulse transmitters that handle transmission pulses consisting of a plurality of subpulses are configured as described above, so gaps are required between the subpulses.
For this reason, there is a problem in that amplitude distortion and phase distortion occur in the subsequent class C amplifier due to power supply fluctuations, temperature changes, etc. in the gap portion.

The present invention was made to solve the problems of the conventional devices as described above, and an object of the present invention is to obtain a pulse transmitting device that can reduce phase distortion and amplitude distortion caused by gaps between subpulses.

[Means for solving problems]

The pulse transmitting device according to the present invention transmits the transmission signals of the plurality of oscillators 1, 2, 9, and 11 into a plurality of pulse trains with a predetermined interval ΔT for each transmission repetition period.
In a pulse transmitter that modulates P _A , P _B , and P _C with pulse modulators 3, 4, and 10, and amplifies the power with a class C amplifier 8 before transmitting, the gap ΔT between pulses in the pulse train or the leading pulse A predetermined interval τ immediately before or both
dummy pulse inserting means 13 and 14 for inserting dummy pulses P _D that are continuous at (τ < ΔT) and have a frequency different from that of the pulse train, and the plurality of pulse trains produced by the class C amplifier are treated as approximately one pulse. It is characterized in that amplitude distortion and phase distortion are reduced by amplification.

[Effect]

In this invention, a dummy pulse is inserted between the subpulses and/or at the beginning of the subpulse train, so that the subpulse train in the transmission time period can be regarded as almost one pulse and amplified in the class C amplifier. This has the effect of reducing output amplitude distortion and phase distortion caused by power supply fluctuations and temperature changes.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a pulse transmitter according to a first embodiment of the present invention, and is an example of a device in which a dummy pulse is inserted into a transmission signal consisting of two sub-pulses. In the figure, 1 and 2 are oscillators that generate two sub-pulse frequencies f _A and f _B ; 9
is an oscillator that generates the dummy pulse frequency f _D ,
3, 4, and 10 are pulse modulators that create sub-pulses P _A , P _B and dummy pulses _PD ; 6 is a power combiner for these; 7 is a phase shifter or variable attenuator controlled for each sub-pulse; 8 is a subsequent stage 5 is a timing generator. Further, 13 is a dummy pulse insertion means consisting of the timing generator 5, oscillator 9, pulse modulator 10, and power combiner 6.

Next, the operation of this embodiment will be explained using the system diagram shown in FIG. 1 and the timing chart shown in FIG. 2. The outputs of the two oscillators 1 and 2 with frequencies f _A and f _B are modulated pulses generated by the timing generator 5.
The pulses are modulated by V _A and V _B by pulse modulators 3 and 4, respectively, to become sub-pulses P _A and P _B. At this time 2
There is a gap ΔT between the two sub-pulses P _A and P _B that is longer than the response time of the subsequent phase shifter or variable attenuator 7.
must be established. The dummy pulse P _D is used to fill this gap, and its pulse width τ
is selected to be as close to ΔT as possible within a range that does not cause cross-modulation with sub-pulses.

Similar to the sub-pulse, this dummy pulse P _D uses the output of the oscillator 9 of frequency f _D to the timing generator 5.
Pulse modulator 1 by the modulated pulse V _D created by
It is created by modulating with 0. These subpulses P _A ,
P _B and dummy pulse P _D are combined by power combiner 6,
Next, each sub-pulse is controlled by a phase shifter or variable attenuator 7, amplified by a class C amplifier 8 at the final stage, and output. At this time, since a dummy pulse P _D is inserted between sub-pulses P _A and P _B , the class C amplifier 8 can amplify these pulses by regarding them as one pulse. For certain sub-pulses P _A and P _B , amplitude distortion and phase distortion due to power supply fluctuations, temperature changes, etc. are reduced.

Next, a second embodiment of the present invention will be described.
Figure 3 shows an example of a configuration in which one pulse modulator is used to create a sub-pulse train, where three sub-pulses are included in one transmission period, and dummy pulses are inserted between each sub-pulse and before the first sub-pulse. An example is shown below. In the figure, 1, 2, 11 and 9 are oscillators for sub-pulses with frequencies f _A , f _B , f _C and dummy pulses with frequency f _D , 12 is a switch for switching the output of these oscillators, and 3 is an oscillator for sub-pulses and dummy pulses. 7 is a phase shifter or variable attenuator controlled for each sub-pulse, 8 is a final stage class C amplifier, and 5 is a timing generator. Reference numeral 14 denotes a dummy pulse insertion means comprising the dummy pulse oscillator 9, switch 12, timing generator 5 and pulse modulator 3.

The operation of this embodiment will be explained using the system diagram in FIG. 3 and the timing chart in FIG. 4. frequency
Four oscillators 1, 2, 11, 9 of f _A , f _B , f _C , f _D
generate three sub-pulses and a dummy pulse frequency, respectively. A desired frequency of the outputs of these oscillators is selected by a switch 12 based on a switching signal generated by a timing generator 5, and is supplied to a pulse modulator 3. Here, this signal C _T is modulated by a modulation pulse V _T generated by a timing generator, controlled for each sub-pulse by a phase shifter or variable attenuator 7, and outputted via a class C amplifier 8. Here, the dummy pulse P _D is created in the same way as in the first embodiment described above, and is created to fill the gap between sub-pulses, but in order to further suppress the amplitude distortion and phase distortion of the leading sub-pulse, It is also added to With these three dummy pulses, sub-pulses P _A , P _B ,
Power fluctuations and temperature changes during the _PC time period are reduced, which reduces sub-pulse amplitude distortion and phase distortion.

Further, in the above embodiment, although the case where a dummy pulse is added only to the beginning of a sub-pulse train is not particularly described, this case also has the effect of reducing the amplitude distortion of the leading sub-pulse.

〔Effect of the invention〕

As described above, according to the pulse transmitter according to the present invention, at intervals of a plurality of pulses or immediately before
Since dummy pulses with different frequencies are inserted at approximately this pulse interval, these multiple pulses can be amplified as almost one pulse train by a class C amplifier, and the class C amplifier can produce amplitude distortion, phase distortion, etc. This has the effect of obtaining less transmission output.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a pulse transmitting device according to a first embodiment of the present invention, FIG. 2 is a timing chart showing its operation, and FIG. 3 is a system diagram of a transmitting device according to a second embodiment of this invention. 4 is a timing chart showing its operation, FIG. 5 is a system diagram of a conventional transmitter, and FIG. 6 is a timing chart showing its operation. In the figure, 1 and 2 are oscillators, 3 and 4 are pulse modulators, 5 is a timing generator, 6 is a power combiner, 7 is a phase shifter or variable attenuator, 8 is a class C amplifier, 9 is an oscillator, and 10 1 is a pulse generator, 11 is an oscillator, 12 is a switch, and 13 and 14 are dummy pulse insertion means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A pulse modulator in which the oscillation signals of a plurality of oscillators 1, 2, 9, and 11 are transmitted as a plurality of pulse trains P _A , P _B , P _C with a predetermined interval ΔT for each repetition period. 3,
In a pulse transmitting device that modulates the pulses at 4, 10 and amplifies the power with a class C amplifier 8 before transmitting, a predetermined interval τ is set at the interval ΔT between pulses in the pulse train, or immediately before or both of the first pulse.
dummy pulse inserting means 13 and 14 for inserting dummy pulses P _D that are continuous at (τ < ΔT) and have a frequency different from that of the pulse train, and the plurality of pulse trains produced by the class C amplifier are treated as approximately one pulse. A pulse transmitter characterized in that amplitude distortion and phase distortion are reduced by amplification.