KR790002004B1 - Method of telecomunication - Google Patents

Abstract

The method of highspeed-high capacity data telecommunication, which could utilize a carrier wave without using a side band and a modulation technology, transmitting a signal pulse and audio signals through an aerial telephone line, was disclosed. pulse of a fixed pulse train in the order of the regualr generation was equivalent to a halfperiodic of carrier wave each. The carrier wave was modulated by modulating amplitude of carrier wave to the equivalent pulse value.

Description

Data communication method

1 is a schematic diagram of a data communication system according to an embodiment of the present invention.

2 is a radio wave diagram showing a standard radio wave form of a carrier wave.

3 shows a sequence of signal pulses

4 is a waveform diagram showing a carrier modulated by the signal pulse shown in FIG. 3 according to the present invention.

5 is a waveform diagram showing a carrier modulated with different types with the same signal pulses according to the present invention.

6 shows a sequence of high frequency signal pulses,

FIG. 7 is a waveform diagram showing a carrier modulated with the signal pulse shown in FIG.

8 is a waveform diagram showing a demodulated carrier wave in a first phase of the demodulation method according to the present invention.

9 is a schematic diagram of a transmission apparatus of a high speed data communication system according to another embodiment of the present invention.

FIG. 10 is a waveform diagram showing a carrier modulated by the modulator shown in FIG.

FIG. 11 is a schematic of a demodulator paired with the modulator shown in FIG.

12 and 13 are graphs showing characteristics of the band filter which can be used in the demodulator shown in FIG.

14 is a schematic of another modulator according to the present invention.

FIG. 15 is a schematic of a demodulator paired with an electrical modulator shown in FIG.

16 is a schematic diagram of a communication system capable of transmitting a predetermined pulse along with a predetermined voice signal according to the present invention.

FIG. 17 is a graph showing the dB / frequency characteristics of band filters that can be used in the electrical communication system shown in FIG.

18 is a schematic diagram of a wireless data communication system according to the present invention.

The present invention relates to a communication method, in particular a data communication method.

In the present invention, communication is generally performed using a plurality of carrier waves each having its own frequency in the allocated frequency band.

Then, the signal pulse train to be transmitted is divided into a sequence of frames, and the allocated signal pulses in each frame are subdivided into sub-orders of pulses corresponding to their own carriers. The signal pulses allocated to the subdivisions of the pulses are sent to half or one cycle of the carrier within the time period corresponding to one frame, and half or one cycle of the carrier is modulated according to the transmitted signal pulses.

Thereafter, all carriers are mixed and modulated by well-known methods and then transmitted over a preferred communication line or broadcast line.

These mixed carriers are strictly separated by a frequency discriminator after reception, and are demodulated separately into subdivisions of the pulses, after which the pulses are rearranged in their original order.

By the above-described method, signal pulses or data are carried in extremely narrow frequencies at extremely high speeds.

The present invention relates to a data communication method, and more particularly to a band compression method for data communication.

Today, large amounts of informative data have reached astronomical numbers, and we need more competent and effective data communication technology.

Thus, various techniques have been proposed, for example, at extremely high frequencies, various kinds of multi-communications and various kinds of modulation techniques.

Nevertheless, the frequency band assigned to a particular communication is very tightly defined, for example, a common public telephone line has a band-pass filter, and its cutoff frequency upper limit is about 3,000 Hz, so that Carriers with frequencies higher than 3,000 Hz cannot be used.

Thus, the maximum speed of communication over a telephone line is usually limited to around 1,200 baud.

For this reason, a large amount of time is required to transmit a small image over a public telephone line using a single device.

Of course, although high speed transfer cameras are used, they are very complex and expensive because of the necessity of using complex electronic data processing machines for information compression.

The primary object of the present invention is to provide a high speed and high density data communication method.

A second object of the present invention is to provide a communication method using a carrier wave without using a wave band.

It is a third object of the present invention to provide a communication method capable of transmitting highway signal pulses much higher than a well-known threshold transmission rate in an allocated communication line or frequency band.

A fourth object of the present invention is to provide a communication method capable of transmitting signal pulses together with audio signals and the like via public telephone lines.

It is a fifth object of the present invention to provide a novel modulation technique that can be harmonized with all kinds of known modulation techniques.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail by an accompanying drawing.

In FIG. 1, a data communication system according to an example of the present invention has a modulator 1, a demodulator 2, a signal pulse generator 3, a timing pulse generator 4, a transmission line 5, and a regenerator 6. FIG.

The signal pulse generator 3 is, for example, analogous to an input to a converter for converting analog to digital, a transmission picture transmitter or a computer, which is a ternary code synchronized with the timing pulse transmitted by the timing pulse generator 4. And signal pulse trains.

The modulator 1 has a carrier generator 7, two monostable elements 8 and 9 (both of which also have their own output logic sub-indicators 10 and 11), respectively. ), Two switching transistors 12 and 13 and three resistors 14, 15 and 16.

The carrier generator 7 is composed of a T-bistable element and a band pass filter (not shown). The waveform of the carrier wave is a sine curve, and their frequencies are the same as the frequency of the timing pulses.

On the other hand, since the monostable elements 8 and 9 are not triggered at the same time and both the switching transistors 12 and 13 are in a conducting state, the amplitude of the carrier wave is as shown in FIG. Likewise, the minimum value is obtained.

Both of the monostable elements 8 and 9 are not triggered when one of the ternary codes representing the logic 0 and the signal pulse is generated, but the signal pulses representing logic 1 are triggered in the monostable element 8. The pulse length is equal to one period of the carrier wave, and this pulse cuts off the switching transistor 12 through the logic display unit 10.

In other words, when the monostable element 8 is triggered, the switching transistor 12 stops conduction and remains non-conducting for one period of the carrier, so the amplitude of the carrier is doubled.

And, since the signal pulse meaning logic 2 is triggered together on the monostable elements 8 and 9, the switching transistors 12 and 13 are both in a non-conducting state for one period of the carrier wave, and thus the carrier wave. The amplitude of is tripled.

Therefore, the carrier wave is modulated as shown in FIG. 4 in accordance with the signal pulse shown in FIG.

Then, the modulated carrier wave is transmitted to the desired receiving apparatus via the transmission line 5.

The demodulator 2 includes a preamplifier 17, a branch amplifier 18, schmitt circuits 19, 20 and 21, a monostable element 22, a logic sub-indicator 23, the delay circuit 24, the diodes 25, 26 and 27, and the suppressor circuit 28. As shown in FIG.

The peak half-cycle peak voltage of the carrier carrying logic 0 is not triggered in Schmidt furnaces 19 and 20 but is triggered in (21), while carrying Logical 1 is not triggered in Schmitt circuit 19 ( Triggered at 20) and (21), carrying Logical 2 is triggered at all Schmitt circuits (19), (20) and (21).

Then, the voltage of the output pulse of the Schmitt circuit 19 becomes the highest value among the Schmitt circuits, the value of the Schmitt circuit 20 becomes the intermediate value, and the value of the Schmitt circuit 21 becomes the minimum value.

On the other hand, the output signal of the preamplifier 17 is amplified by the branch amplifier 18 and supplied to the monostable element 22.

The monostable element 22 is triggered at the beginning of the second half cycle of the carrier to output a short pulse train of the same frequency as the carrier frequency.

These pulses are converted by the logic sub-indicator 23, delayed by the delay circuit 24, and input into the suppressor circuit 28 when the amplitude of the carrier wave reaches each of the peak values of the later half cycle. This is because the delay time of the delay circuit 24 is equal to 1/4 of two periods of the carrier wave.

Therefore, the suppressor circuit 28 opens simultaneously whenever the amplitudes of the carrier waves reach their peak values in their later half cycles, and passes the output pulses of the Schmitt circuits 19 to 21. These output pulses operate the regenerator 6 to reproduce the signal patterns and the like transmitted by the apparatus.

The number of monostable elements of the modulator 1 and the Schmitt circuit of the modulator 2 should be measured according to the type and type of signal to be transmitted.

And in the above embodiment, the length of the output of the monostable elements 8 and 9 is equal to the length of one period of the carrier, but this may be equal to the length of the half period of the carrier. In the latter case, the carrier wave is modulated as shown in FIG. 5 in accordance with the signal pulse shown in FIG.

Further, if the harmonic signal pulses shown in FIG. 6 are transmitted, the carrier wave can be modulated with the harmonic signal pulses as shown in FIG. The carrier modulated in this form is converted to the waveform shown in FIG. 8 by full wave rectification, received, amplified, and then demodulated.

By this method, the transmission speed is doubled, but this requires a transmission line of good quality.

In general, the modulation scheme shown in FIG. 4 is recommended when using a poor transmission line, for example a public telephone line, because no change in DC current occurs in this case.

In this case, spurious wave peaks often appear in the half-period of the carrier that carries the logic signal, especially in the low amplitude propagation following the high amplitude propagation, so that modulation It should be done every half cycle of the second half of the carrier that carries the signal.

9 shows an example of a transmission apparatus capable of performing multiple transmission using a plurality of carriers having different frequencies.

In Fig. 9, reference numeral 29 denotes a signal pulse generator for generating a double signal pulse train, reference numeral 30 denotes a modulator, reference numeral 31 denotes a timing pulse generator, and reference numeral 32 denotes a delay circuit.

The modulator 30 includes a main register 33, a distributor 34, an auxiliary register 35, 36 and 37, modulators 38, 39 and 40, and a mixed circuit 41. And a preset counter 42, a delay circuit 43, and an output terminal 44.

The timing pulse generator 31 has four output terminals 31-1, 31-2, 31-3 and 31-4, from which 6,750, 1,500, 2,250 and 3,000 Hz, respectively. Send the timing pulse train.

The main register 33 is composed of nine vice-table elements, flip-flops 33-1 to 33-9 and eight delay circuits 33-10 to 33-17. Digit shift registers, and the distributor 34 is a data processing gate circuit having nine AND circuits 34-1 to 34-9.

The auxiliary register 35 is two digit shift registers composed of two vise table elements 35-1 and 35-2 and one delay circuit 35-3. The two stored digit data located at the bottom of) are moved and stored.

The auxiliary register 36 has three digit shifts consisting of three visetable elements 36-1, 36-2 and 36-3 and two delay circuits 36-4 and 36-5. A register, in which three stored digit data located in the middle of the main register 33 are moved and stored.

The auxiliary register 37 includes four visetable elements 37-1, 37-2, 37-3 and 37-4 and three delay circuits 37-5, 37-6. And four digit shift registers composed of (37-7), wherein four stored digit data located above the main register 33 are moved and stored.

The frequency of the 6,750 Hz timing pulses generated at the output terminal 31-1 of the timing pulse oscillator is equal to the sum of the frequencies of the timing pulses transmitted from the other output terminals.

The 6,750 Hz timing pulse is used as a shift pulse for the main register 33 in the meantime, while it is used as a timing pulse to control the signal pulse generator 29 through the delay circuit 32, and also the main register ( 33 is used as an instruction pulse for moving the recording of the 33 to the auxiliary registers 35, 36, and 37 through the preset counter 42 and the delay circuit 43.

The signal pulse generator 29 is, for example, a transmission picture transmitter that scans an image and converts it into a synchronous double pulse train.

Specifically, the transmission picture transmitter has an optical detector, which is synchronized with a 6,750 Hz timing pulse and under what threshold is the brightness of the scanning point of the image. Converts and transmits a double signal pulse that indicates whether it is present. The preset counter 42 causes a sensitive pulse to be sent every nine input pulses.

The output pulses emitted by the timing pulse generator 31 are input to the main register 33, which is nine digit shift registers, and the nine moment bits of the output pulse are written to the main register 33, which are preset counters. The command pulse sent by (42) moves the auxiliary registers (35), (36) and (37) to a new place.

Since auxiliary registers 35, 36, and 37 are driven by 1,500, 2,250 and 3,000 Hz timing pulses, respectively, they each transmit serially stored data in exactly one frame of time, and nine signal pulses per round. Is input to the main register 33, which is synchronized with its own timing pulse.

Modulators 38, 39, and 40 are similar to each other, and modulator X (X represents (38), (39) or (40)) is carrier generator Xl, monostable element X-2, logic It consists of sub-indicator X-3, switching transistor X-4 and resistors X-5 and X-6.

However, carrier generators 38-1, 39-1, and 40-1 generate 1,500, 2,250, and 3,000 Hz carriers, respectively, and monostable elements 38-2, 39-2, and The preset time of 40-2 is equal to 1 / 1,500, 1 / 2,250 and 1 / 3,000 seconds, respectively.

The operation of these modulators 38, 39, and 40 is similar to that of the modulator 1, for example, when the output of the auxiliary register 36 is zero, the switching transistor 39-4 is turned on so that the carrier wave The amplitude of the signal becomes low level, but when the output of the auxiliary register 36 is 1, the monostable element 39-2 is triggered so that the switching transistor 39-4 stops conduction so that the amplitude of the carrier wave increases. do.

The amplitude of the carriers is made every two zero-cross points of these switching carriers, ie, at the moment when zero is reached as the synchronous voltage of the carriers increases. Thus, the carrier waveforms between the zero-cross-points described above are always very similar to the sine curves, but their amplitude is governed by the corresponding output signals carried by the corresponding auxiliary registers.

The carrier wave modulated by the former modulator is shown in FIG. After the three modulated carriers are mixed in the mixing circuit 41, the receiving shaft shown in FIG. 11 is transmitted via a telephone line or the like.

In FIG. 11, reference numeral 45 denotes a demodulator, 46 denotes a regenerator, and demodulator 45 denotes an input terminal 47, a preamplifier 48, a band pass filter 49, 50, and ( 5l), amplifiers 52, 53 and 54, monostable elements 55 to 60, receive resistors 61, 62 and 63, final register 64, data processing The gate circuit 65, the delay circuits 66, 67 and 68, the AND circuit 69, the multiplier 70 and the output terminal 71 are comprised.

Receive registers 61, 62, and 63 are assembled similarly to the auxiliary registers 35, 36, and 37, respectively, and the final register 64 is the main register 33 and Similarly, and the data processing gate circuit 65 is configured similarly to the distributor 34.

The dB / frequency characteristics of the band pass filter are shown in FIG. 12, and the upper cutoff frequencies of the band pass filters 49, 50, and 51 were 1,500, 2,250, and 3,000 Hz, respectively.

Therefore, the band pass filter acts as a frequency discriminator all to separate the three mixed carriers.

Monostable elements 55, 56, and 57 all have the same threshold level and short preset time and are not triggered by the peak amplitude of the carrier's small amplitude, but by the peak amplitude of the carrier's high amplitude Trigger on half period of second half of carrier.

In other words, the monostable elements 55, 56 and 57 demodulate the corresponding carriers modulated by the modulators 38, 39 and 40 into respective pulse trains.

On the other hand, the separated carriers are amplified by the amplifiers 52, 53, and 54, respectively, and are triggered by the monostable elements 58, 59, and 60.

Monostable elements 58, 59, and 60 are triggered at 21 zero-cross-points of the corresponding carrier, where the amplitude of the carrier is switched and transmits a sensitive pulse train, which is a receive register 61. ), And are used as shift pulses for (62) and (63).

Therefore, the signal pulses demodulated by monostable elements 55, 56, and 57 are stored in receive registers 61, 62, and 63, respectively.

On the other hand, the output pulses of the monostable elements 58, 59, and 60 are input to the AND circuit 69 through the delay circuits 66, 67, and 68, respectively.

Delay circuits 66, 67 and 68 are used to synchronize the output pulses of the carriers, ie 1,500, 2,250 and 3,000 Hz carriers.

Since the transfer rates of the above-described carriers are different from each other, the output pulses of the monostable elements 58, 59, and 60 are not always synchronized, so that the difference in the transfer rates or the pace of the carriers are compensated for. Delay circuits 66, 67 and 68 are installed to synchronize one output pulse.

The timing between the output pulses of the AND circuit 69 is equal to the time of one frame above, unless a frequency offset occurs on the transmission line. Therefore, nine bits of the transmitted signal are stored in the receiving registers 61, 62 and 63 within this time period.

If a frequency offset occurs on the communication line, the above storage is done without any difficulty or mistake.

At the end of the above-mentioned period, the data stored in the reception registers 61, 62, and 63 is transferred to the final register 64 through the data processing gate circuit 65.

The multiplier 70 transmits a 6,750 Hz timing pulse that is synchronized with the output pulse of the AND circuit 69, which is used as a shift pulse for the final register 64.

Therefore, the stored data is transmitted to the player 46 within the time of the next one frame, while the next nine bits of the signal will be received and stored in the receiving registers 61, 62 and 63.

Therefore, according to this embodiment, data can be transmitted at a speed of 6,250 baud over the telephone line without mistakes.

In this example, 1,500, 2,250, and 3,000 Hz carriers were used, but 750, 1,500, and 3,000 Hz carriers are used, and the frequency is doubled when it is necessary to use poor quality lines, for example long distance telephone lines. .

In this case, the band pass filter should have the dB / frequency characteristics shown in FIG. 13 and have the 750, 1,500, and 3,000 Hz upper cutoff frequencies.

14 shows a modulator for transmitting gray code.

In Fig. 14, reference numeral 37 'is an auxiliary register similar to the auxiliary register 37 shown in Fig. 9, and 40' is a modulator used for the space of the modulator 40 shown in Fig. 9.

In this case, the brightness of the image at the scanning point is represented by two bits of the double recorded value as shown in the first table.

And every auxiliary register has an even number of digits, which is actually twice the digit of the auxiliary register shown in FIG. 9, and a pair of brightness data is stored.

The modulator 40 'includes the T-vice-table element 72, the AND circuits 73, 74 and 75, the monostable elements 76, 77, 78 and 79, the output logic. Sub-indicators 80, 81 and 82, AND circuits 83 and 84, delay circuit 85, carrier generator 86, switching transistors 87, 88 and 89, It consists of registers 90, 91, 92 and 93 and an output terminal 94.

The monostable element 76 supplies the sub register 37 'with a sensitive pulse every two shift pulses. The carrier generator 86 then transmits a sine wave whose frequency is equal to half the frequency of the shift pulse described above.

When the write value on the most two bits of the auxiliary register 37 'is [00], that is, when both the T-vice table elements 37'-4 and 37'-3 are reset, the AND circuit 73 is reset. , 74 and 75 do not transmit pulses at all, so the monostable elements 77, 78 and 79 are not triggered, and all switching transistors conduct after the amplitude of the carrier is at its lowest level. It becomes a state.

When the light gray record value 01 appears on the T-vice table elements 37'-4 and 37'-3, the AND circuit 73 is a monostable element because the T-vice table element 37'-3 is set. The pulse is passed by the passage of 76.

Therefore, the monostable element 77 is triggered and the switching transistor 87 stops conduction for one period of the carrier wave. Therefore, the amplitude of the carrier is increased to reach a certain level.

When the dark gray recording value l0 appears, the vise table elements 37'-4 are set, and the AND circuit 74 passes the output pulse of the monostable element 76. Therefore, the monostable element 78 is triggered, and the switching transistors 87 and 88 stop conduction for one period of the carrier wave. Therefore, the amplitude of the carrier increases to a higher level.

When the recording value [11] appears, both the T vice table elements 37'-4 and 37'-3 are set, the AND circuit 75 passes the pulse, and the monostable element 79 Is triggered, and all switching transistors 87, 88, and 89 stop conduction, so that the amplitude of the carrier reaches its highest level.

Therefore, the carrier wave is modulated to the brightness record value in four steps. This modulated carrier is modulated by itself or by the above modulation method, but transmitted after being mixed with other carriers having its own frequency.

FIG. 15 shows a demodulator corresponding to the modulator 40 'shown in FIG.

In Fig. 15, (47), (48), (54), (60), and (68) are the same as those shown in Fig. 11.

And (49 '), (50') and (51 ') are band filters, (57-1), (57-2) and (57-3) are Schmitt trigger circuits, and (63') are receive registers ( 95 is a delay circuit, 96, 97 and 98 are AND circuits, 99 and 100 are input logic sub-indicators, 101 and 102 are OR circuits, and 103 are radio waves. The full-wave rectifier 104 is a monostable element and 105 is a delay circuit.

The Schmitt trigger circuit 57-1 has the highest triggering level among the three Schmitt trigger circuits 57-1, 57-2, and 57-3, and the peak of the carrier modulated with the recording value [11]. Triggered in accordance with the voltage, the Schmitt trigger circuit 57-2 has an intermediate triggering level among them, and is also triggered in accordance with the peak voltage of the carrier corresponding to the recording value [01].

The preset time of the delay circuit 95 is equal to a quarter period of the carrier wave.

The output wave of the band pass filter is triggered in the monostable element 104 after rectifying by the full wave rectifier 103.

The monostable element 104 transmits a sensitive pulse train, the frequency of which is twice as high as that of the carrier wave.

The output pulse of the monostable element 104 is used as a shift pulse for the receive register 63 '.

The return conveying the recording value [00] does not trigger the Schmitt trigger circuit, in which case the recording value [00] is at least two digits of the receiving register 63 'via the OR circuit 101 and 102. Are stored in.

The carrier wave carrying the recording value [01] does not trigger the Schmitt trigger circuits 57-1 and 57-2, but triggers the Schmitt trigger circuit 57-3 and the Schmitt trigger circuit 57-3. The output pulse is input and stored in the lowest digit of the receiving register 63 'via the AND circuit 98 and the OR circuit 102.

The carrier carrying the recording value [01] does not trigger the Schmitt circuit 57-1, but triggers the Schmitt trigger circuits 57-2 and 57-3, and outputs the Schmitt trigger circuit 57-2. Is input and stored in the second digit of the receive register 63 'via the AND circuit 97 and OR circuit 101, but the output of the Schmitt trigger circuit 57-3 will pass through the AND circuit 98. Since the write value 10 is stored in at least two digits of the receiving register 63 '.

The carrier which carries the recording value [11] triggers all the trigger circuits 57-1, 57-2 and 57-3, and the output of the Schmitt trigger circuit 57-1 is input, and the AND circuit Through 96 and OR circuits 101 and 102, it is stored in at least two digits of the receiving register 63 '.

After the demodulation and storage has been performed, the monostable element 104 gives two shift pulses to the receive register 63 ', after which the receive register 63' has received the one frame after the next demodulation and storage has been performed. Fill the received record within the time of.

The moment all the registers are filled, all the records stored in these registers are transferred to the final register by the method shown in FIG. 11 and transferred to the desired generator.

16 is a communication system that can be used to carry data communication data with a bi-directional conversation by telephone, for example over a public telephone line.

In Fig. 16, numeral 106 is a handset, 107 is a handset, 108 is a telephone line, 109 is a player, and 110 and 111 are telephone receiver circuits.

The transmitter 106 includes a timing pulse generator 112, a signal pulse generator 113, a modulator 114, a telephone transmitter 115, a band pass filter 116 and 117, and a mixing circuit 118. .

Modulator 114 includes carrier generator 114-1, monostable element 114-2, output logic sub-indicator 114-3, switching transistor 114-4 and resistors 114-5 and 114; -6).

The operation of the timing pulse generator 112, the signal pulse generator 113, and the modulator 114 is similar to the operation of the above-described apparatus shown in FIG. 1 or FIG.

The handset 107 is composed of an amplifier 119, a band pass filter 120, and 121 a monostable element 122 and a telephone handset 123.

The band filters 116, 117, 120, 12l, 124, and 126 each have the dB / frequency characteristics shown in FIG. The upper cutoff frequency and the lower cutoff frequency of the band pass filter 116 and 120 at 3,000 Hz and 1,600 Hz, respectively, and the upper cut off frequencies of the band pass filters 117, 121, 124 and 126, respectively. It is recommended to fix at 1500Hz.

Typically, telephone lines have a bandpass filter having a 300 Hz bottom cut off frequency and a 3,000 Hz or more top cut off frequency.

However, if the frequency band for the conversation is limited to within the range of 300-1,500, telephony is still within the range of possibilities.

Voice signals are transmitted from the telephone handset 115 to the telephone handset 123 and from the telephone handset 125 in this direction of the telephone handset 127, while the signal pulses originating from the signal pulse generator 113 Modulated by modulator 114 and transmitted via telephone line 108 to handset 107, demodulated by monostable element 122 and supplied to regenerator 109. This communication system is suitable for transmission photographs or visual telephones.

18 shows a wireless communication system according to an embodiment of the present invention. In FIG. 18, 128 is a transmitter or modulator similar to the transmitter or modulator shown in FIGS. 1, 9, 14, or 16 degrees, 129 is a radio carrier generator, 130 is a well known modulator, 131 is a transmit antenna, 132 is a receive antenna, 133 is a detector, 134 is a well-known demodulator, and 135 is a receiver similar to that shown in FIG. 1, 1l, 15 or 16 degrees. Or a demodulator.

A well-known modulation method for broadcasting, amplification modulation, frequency modulation, phase modulation, etc. can be used for this communication system.

This communication system is well suited for slow-scan television for radio transmission photography and radio ham.

The embodiments described herein are representative of suitable forms of the invention, but they are provided for purposes of illustration and are not intended to limit the invention.

Claims (1)

In modulating and transmitting a carrier wave into a pulse train, each half-cycle of the carrier between all zero-cross-points corresponds to a pulse of a predetermined pulse train in a regular generation order, and modulates the amplitude of the carrier wave to a corresponding pulse value. Communication method characterized in that the modulation.

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