JPS6161307B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-value transmission method that can be used, for example, in communication transmission.

The three-value transmission method according to the present invention has a three-value logic signal composed of a combination of pulses of positive polarity, zero amplitude, and negative polarity. In other words, the present invention makes it possible to add another degree of freedom in logic to binary transmission, which has been mainly used in the past, and the scope of its application can be expanded without being limited to communication transmission. It is something that can be done.

The present applicant previously proposed a transducer having a configuration as shown in FIG. This consists of a piezoelectric substrate 1, an interdigitated interdigitated interdigitated electrode 2 provided on the surface of the substrate 1, and a flat plate electrode 3 provided on the back surface of the substrate 1 opposite to the interdigitated interdigitated electrode 2. It consists of In addition, A and B
0 is the terminal of the interdigital electrode 2, and O is the terminal of the flat electrode 3. With the above configuration, terminal O is used for grounding, and electrode terminals A-O and B-O are connected to each other.
By applying electrical signals with a 180° phase difference, a transducer with excellent conversion efficiency could be obtained.

The present invention further develops the above technology, focuses on the fact that the above-mentioned transducer functions as a ternary logic device, and aims to provide a ternary transmission method that can be used, for example, in communication transmission. . A feature of the present invention for achieving this purpose is to convert a three-value logic signal composed of a combination of pulses of positive polarity, zero amplitude, and negative polarity into a signal S having a predetermined frequency and phase, and a signal S with zero amplitude. ₀ ,
A signal consisting of a combination of a signal with the same frequency and a phase shift of 180° with respect to the above S signal is used as the transmission output of the transmission line, and the phase difference between the reference signal and the input signal applied between the interdigital electrode and the flat electrode is According to
The transmission output signal is applied to the input side _of a receiving means provided on the receiving side of the transmission line, and the transmission output signal is applied to the input side of the receiving means provided on the receiving side of the transmission line, and This is a three-value transmission method in which the transmission output signal is obtained as a difference in amplitude level on the output side by a reference signal applied to another terminal. Examples will be described below with reference to the drawings.

FIG. 2 shows an example of a circuit on the transmitting side of the three-value transmission system according to the present invention, where 4 is a photocoupler composed of, for example, a photodiode and a phototransistor, 5 is an electronic switch controlled by the photocoupler 4, and 6 is an operation amplifier. ,
R ₁ to _{R 6} are resistors, and C ₁ and C ₂ are capacitors.
Note that A, B, and C are terminals. The three-value logic signal in the three-value transmission system of the present invention is composed of a combination of pulses of positive polarity, zero amplitude, and negative polarity. Applying such a three-value logic signal to the A terminal and B
If a sinusoidal alternating current (frequency f _C ) is applied to the terminal,
The opening/closing of the electronic switch 5 is controlled according to each pulse of positive polarity, zero amplitude, and negative polarity, and a signal S having a carrier of frequency f _C and an output signal of zero amplitude are sent to the C terminal via the operational amplifier 6. _S0 ,
An output signal composed of a combination of signals phase-shifted by 180° with respect to S is obtained. The transmitting side sends out this signal to the transmission path as a transmission output.

On the other hand, on the receiving side, it is necessary to identify the signal transmitted from the transmitting side via the transmission path, and for this reason, as a device on the receiving side of the transmission path, a device such as the one shown in Fig. 3 is used.
Use value logic devices. In FIG. 3, reference numeral 7 denotes a piezoelectric substrate, 8 and 9 interdigitally configured interdigital interdigital interdigital electrodes, and 10 faces the first interdigital electrode 8 on the back side of the substrate 7. A flat electrode 11 is provided on the back surface of the substrate 7, facing the second interdigital electrode 9. Further, A is a terminal of one electrode 8a constituting the first interdigital electrode 8, B is a terminal of the other electrode 8b, A' is a terminal of one electrode 9a constituting the second interdigital electrode 9, B' is a terminal of the other electrode 9b. O is a terminal of the flat electrode 10, and O' is a terminal of the flat electrode 11. The interdigital electrodes 8 and 9 transmit signals corresponding to S, S ₀ , to the second interdigital electrode 9 according to the phase difference between the reference signal applied to the first interdigital electrode 8 and the input signal. It is assumed that the configuration is such that outputs of different amplitudes are generated.

Under the above configuration, S as a reference signal, that is, a signal having a carrier of frequency f _C is applied to the A-O terminal, and S, S ₀ transmitted from the transmitting side is applied to the B-O terminal. , is applied. Now, if the input signal to the BO terminal is S, that is, a signal with frequency f _C ,
Since a signal of the same frequency and same phase is applied as a reference signal to the A-O terminals, almost no sound waves are excited, and therefore the terminals A'-O' and B'-O' of the interdigital electrode 9 are The output is a signal S ₀ with zero amplitude. Next, when the input signal at the B-O terminal becomes _S0 , a sound wave is excited by the reference signal S, and the sound wave propagates through the substrate 7 to the interdigital electrode 9 on the output side.
It converts electrically and outputs S to terminals A'-O' and S to terminals B'-O'. Furthermore, when the input signal to the BO terminal is The output obtained at is maximum, and its amplitude is larger than S or, S- at terminal A'-O' and 〓 at terminal B'-O'.
〓〓 becomes. Therefore, the transmitted signal can be easily identified because it can be determined by its amplitude level. Note that terminals A′-O′ and
Although the output signals of B' and O' have a phase difference of 180° from each other, either or both may be used depending on the need.

Figure 4 shows the results of experiments confirming the ternary transmission method according to the present invention. Figure 4a shows the transmission signal of the ternary transmission method according to the present invention observed with an oscilloscope, and Figure 4b shows the ternary transmission method according to the present invention. The output signal on the receiving side of the system was observed using an oscilloscope. As the configuration of the logic device in the above experiment, polarization treatment was performed in the thickness direction.
Piezoelectric ceramic manufactured by TDK (Tokyo Denki Kagaku Kogyo Co., Ltd.)
SAW-4 material was used. Board length 25mm, width 12
mm, thickness 0.1mm. In addition, the interdigital electrode has a period length of 840 μm and 5 periods, and the center frequency is
It is 4.08MHz. Signal A in FIG. 4a is a three-value logic input signal consisting of impulses of positive polarity, zero amplitude, and negative polarity, and B is the transmission output signal of the circuit of FIG. 2, which is composed of S, S ₀ , ing.
S, have the same frequency but a 180° phase difference. C in FIG. 4b is a timing pulse, and signal D is an output signal of the ternary logic device. As is clear from the waveform shown in (d), it was confirmed that an output signal consisting of three different amplitude levels could be obtained. Note that the same thing is possible when the polarization axis direction of the substrate of the ternary logic device is both perpendicular to the thickness and the propagation direction of the sound wave.

The above results were obtained by exciting Lamb waves using a piezoelectric substrate as a three-value logic device, but piezoelectric thin films such as zinc oxide (ZnO) and cadmium sulfide (CdS) A similar effect can be obtained in a device configured to use surface acoustic waves by providing the piezoelectric layer on a non-piezoelectric substrate such as glass or fused silica.

As explained above, in the three-value transmission system according to the present invention, three-value logic input signals of positive polarity, zero amplitude, and negative polarity are transmitted as signals with the same frequency and zero amplitude, whose phases are shifted by 180 degrees from each other. and inputting the signal to a ternary logic device on the receiving side,
By using the separately input reference signal, an output signal having an amplitude level corresponding to each input signal is obtained on the output side, so it is possible to add another logic to the binary transmission that has been mainly used in the past. It becomes possible to add degrees of freedom.

[Brief explanation of the drawing]

FIG. 1 shows an example of the configuration of a transducer, FIG. 2 shows an embodiment of the ternary transmission system according to the present invention on the transmitting side, and FIG. 3 shows an embodiment of the ternary transmission system according to the invention on the receiving side. Figures 4a and 4b are experimental examples of the ternary transmission system according to the present invention. 4; Photo cutter, 5; Electronic switch, 6;
Operational amplifier, 7; substrate, 8, 9; interdigital electrodes, 10, 11; flat plate electrodes.

Claims (1)

[Claims] 1 A ternary logic signal consisting of a combination of pulses of positive polarity, zero amplitude, and negative polarity is divided into a signal S having a predetermined frequency and phase, a signal S ₀ with zero amplitude, and a phase shift of 180° with respect to the above signal S. A transmitting means for outputting a signal consisting of a combination of signals having the same frequency to be transferred, a transmission line for transmitting the signal, a piezoelectric substrate, and two interdigitally configured interdigital interdigitated substrates provided on the substrate. It consists of an electrode and two flat electrodes provided on the back surface of the substrate facing each of the electrodes, and a reference signal and an input signal are applied between the first interdigital electrode and the first flat electrode. On the receiving side of the above-mentioned transmission line, the transmission line is composed of a ternary logic device that generates outputs of different amplitudes corresponding to S, S ₀ , on the second interdigital electrode and the second plate-like electrode according to the phase difference between . and receiving means provided, and when S is applied as the reference signal and S, S ₀ is applied as the input signal, the input signal is converted to a difference in amplitude level and is output to the output side of the second interdigital electrode. A three-value transmission method that is characterized by the ability to obtain