JPS62213431A - Signal transmission equipment - Google Patents

Abstract

PURPOSE:To miniaturize and simplify the equipment and to prevent cross modulation between equipments by applying electromagnetic coupling between a coil of a resonance circuit at the transmission side and a coil of an oscillation circuit at the reception side to send information between nearby distances. CONSTITUTION:When the equipment 20 approaches the equipment 10, coils L2, L1 of a resonance circuit 2 are being coupled, a voltage signal E is induced by the oscillation of an oscillation circuit 10 in the coil L2 of the resonance circuit 2 and the voltage is detected by a level detection circuit 25. When the detection level exceeds a threshold value, a frequency division circuit 26 and the control circuit 22 start their operation. Since the frequency division circuit 26 supplies a clock signal C to the circuit 22, the control circuit 22 reads the data in the memory 23 to control the on/off of the switching element 21 based on the data. The on-off state of the switching element 21 is detected by a demodulation circuit 13 at the equipment 10 side and received as information.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention A resonant circuit including a coil is provided on the transmitting side, and the resonant state of this resonant circuit is switched depending on the data to be transmitted. On the receiving side, an oscillation circuit including the above-mentioned coil and a coil having an electromagnetic induction coupling port is provided.

,I:,Through the electromagnetic inductive coupling of the memory coil, its oscillation output changes in accordance with the switching of the resonant state, and this change is detected by the demodulation circuit.

The data to be transmitted is stored in memory, preferably non-volatile memory. Therefore, data can be freely rewritten and data of arbitrary length can be set.

Table of contents (1) Green leaves of the invention (2) Overview of the invention (2, 1, Name of the invention (2, 2) Structure 9 of the invention and effects (3) Description of embodiments (3, 1) Principle of information transmission (3,2) Location relationship of transmitting and receiving devices (3,3) Electrical configuration and operation of transmitting and receiving devices (1)
BACKGROUND OF THE INVENTION This invention relates to apparatus for achieving signal transmission over close range.

In general, a wireless communication system consists of a transmitting device and a receiving device. The device transmits data or information to be transmitted onto some kind of propagation energy medium (carrier), and the receiving side receives the carrier and converts it into information. do. This communication system is suitable for communication over relatively long distances. The transmitter side requires a high-power circuit for carrier generation, output, etc., and its configuration is 1um, and the receiver side has a different configuration, such as having to amplify the received signal before processing. This led to the process becoming more complicated and larger. Furthermore, the problem of interference occurs when many transmitting and receiving devices are placed adjacent to each other due to the distance between the carriers that propagate in the air.

For information transmission over thousands of distances, for example, several centimeters, a large-scale communication device such as the one described above is not necessary, and it is desired to realize an information transmission device suitable for this purpose.

(2) Summary of the invention (2.1) Purpose of the invention This invention... Suitable for transmitting information over close distances of several centimeters or less. The present invention aims to provide a signal transmission device that can be simplified in configuration and miniaturized.

(2.2) Structure of the invention. Functions and Effects The signal transmission device according to the present invention includes a resonant circuit including a switching element and a coil for switching a resonant state, and a memory for storing data.
and a transmitter equipped with a control circuit that controls the switching element according to data read from the memory, and an oscillation circuit including a coil that can be electromagnetically coupled to the coil of the resonant circuit, and an output of the oscillation circuit. It is characterized by comprising a receiving device equipped with a demodulation circuit that detects changes. Preferably, the memory is a non-volatile memory.

In the signal transmission device according to the present invention, the transmitting device side includes a circuit for generating a carrier.

There is no need for an amplifier circuit or the like to excite an antenna or the like for carrier transmission, and it is possible to reduce current consumption, simplify the configuration, and downsize. Since the current consumption is low and it is possible to use a battery as a power source, it can be especially attached to a moving object and applied to the communication between the moving object and the stationary side. Also.

On the receiver side, since the output state of the oscillation circuit changes in accordance with the transmitted data, a conventional receiving amplifier circuit or the like is not required, and the configuration is simplified. Furthermore, since it utilizes RI magnetic coupling between the coil of the resonant circuit on the transmitting side and the coil of the oscillating circuit on the receiving side, it is suitable for transmitting information over close distances. In addition, almost no propagation energy is radiated, making it possible to prevent interference between devices or induction disturbances affecting other devices. In this invention,
Furthermore, since the transmitter is equipped with a memory for storing data, the data can be rewritten in the transmitting device, and data of arbitrary length can be set.

(3) Description of Embodiments (3.1) Principle of Information Transmission FIG. 1 shows the principle of transmitting data or information in a signal transmission device that utilizes electromagnetic inductive coupling between two coils.

The oscillation circuit 1 is an LC oscillation circuit, and its coil (inductance) L and resistance bone r1 are specially drawn out and shown. The resonant circuit 2 is constructed by connecting reactance elements of a coil L and a capacitor (capacitor u) C2 in series, and a switch SW is provided in the closed loop. , 1 and the resistance bone r2 of the actance element are also shown. The coil L of such an oscillation circuit 1! and the coil L2 of the resonant circuit 2 face each other and are electromagnetically coupled by a mutual induction coefficient M.

In the above circuit configuration, when the switch SW is closed (switch SW is on), the impedance Zl when looking at the resonance circuit 2 from both ends a-a of the coil L1 of the dual oscillation circuit 1 is expressed by the following equation.

Z mr +jωL1 10ω2M21 [“ +j (ωL −1/ωC2)] [
ω2C2r2+(ω2C2L2-1)2] As is clear from this equation, the coil of one oscillation circuit 1 is connected to the resonant circuit 2.
When the coil L2 is inductively coupled, the loss resistance of the oscillation coil of the oscillation circuit 1 increases and the effective inductance changes (increases or decreases) in general terms, but when considered more specifically, the following results occur.

(1) When the oscillation frequency f1 of the oscillation circuit 1 and the resonance frequency f2 of the resonant circuit 2 are equal (t, -f2) In this case, the loss resistance becomes maximum, but the effective inductance does not change. The oscillation frequency f1 of the resonant circuit 1 also does not change.

(2) When the oscillation frequency f1 of the oscillation circuit 1 and the resonant frequency f of the resonant circuit 2 are different (f #f, both frequencies are relatively close to each other) In this case, the loss resistance increases, but the above (1) The amount of increase is smaller than in the case where the effective inductance changes. The change in effective inductance varies depending on the magnitude relationship between the frequencies f 1 and f 2 and exhibits a linear trend.

When f is smaller than f2, the effective inductance increases.

This lowers the oscillation frequency of the oscillation circuit 1. If this is expressed as (f, -ΔF).

The relationship (f - ΔF)<f<f2 holds true.

When f > f2, the effective inductance decreases to 1
The oscillation frequency of the oscillation circuit 1 becomes higher. This is (f + Δ
F), we obtain the relationship (fl+ΔF)>fl>f2.

When the switch SW is open (switch SW off), the presence of the resonant circuit 'NI2 has almost no effect on the oscillation circuit 1.

Therefore, turning on the switch SW in the resonant circuit 2,
When turned off, the corresponding 2
The characteristics (amplitude and frequency) of the oscillation output of the oscillation circuit 1 change. When this is amplitude demodulated or frequency demodulated, the demodulated signal represents the on/off state of the switch SW.

When some information is expressed by the on/off state of the switch SW of the resonant circuit 2, this information appears in the oscillation circuit 1 as a change in its oscillation output, so the oscillation is generated from the resonant circuit 2 side. The above information will be transmitted to the circuit 1 side. Specifically, the above frequency f
, f in the range of about 100 to 500 KHz may be used.

Also, the distance between the two coils L and L2 is maximum 5QI
I+< leprosy.

(3, 2) Arrangement relationship between transmitting and receiving devices FIG. 2 shows the arrangement relationship between the transmitting device 20 and the receiving device 10 that constitute the signal transmission device.

The receiving FD device 10 is composed of a receiving head 11 and a signal processing circuit 12 that processes a received signal, and these are connected by a transmission line. However, the receiving radar 11 may be built into the case or housing of the signal processing circuit 12 shown by the chain line.

The transmitting device 20 and the receiving device 10 (or its receiving head II) are arranged and fixed so as to face each other at a close distance, or at least one of the device 20 and the IO is configured to move. Ru. for example,
When the transmitting device 20 moves across in front of the receiving device IO as shown by the arrow Y1 or moves in the direction approaching the receiving device 11 as shown by the arrow X1, the two devices 10 and 20 approach each other. At this time, data or information is transmitted from the transmitting device 20 to the receiving device 10 based on the information transmission principle described above.

In a mode in which the transmitting device 20 moves, the transmitting device 20 is attached to a pallet, box, article, etc. that is conveyed by a conveying device, or attached to an automatic guided vehicle, etc.

The receiving device 10 may be moved.

Both devices IO and 20 may be moved.

”-The oscillation circuit l described above is connected to the receiving head 11 (receiving device 10
), the resonant circuits 2 are housed in the transmitting devices 20, respectively. These receiving heads 11 and transmitting devices 20
As shown in FIG. 3, the coils L1 and Lz are respectively provided in a part of their cases 19 and 29. When these devices 10 (11) and 20 are arranged and fixed as shown in FIG.
When these coils L1 . L2 faces each other and is electromagnetically coupled to each other. In order to ensure that the distance d (for example, PJi c+n ) between the coils L and L2 that can be inductively coupled is as large as possible so that information can be transmitted sufficiently,
High magnetic permeability cores (eg ferrite cores) 18,28 are used around the coils L 1 , L 2 , respectively.

(3, 3) Electrical configuration and operation of transmitting and receiving devices Signal transmission between the transmitting device and the receiving device is roughly divided into two-frequency demodulation method and amplitude demodulation method according to the information transmission principle described in 1-1. A specific example of the nine-frequency demodulation method performed by the following will be described below. It goes without saying that the present invention is also applicable to amplitude demodulation type devices.

FIG. 4 shows the electrical configuration of a signal transmission device that operates using a single frequency demodulation method, and this device is composed of a transmitting device 20 and a receiving device 10. FIG. 5 is a waveform diagram showing the operation.

In FIG. 4, the transmitting device 20 includes a resonant circuit 2, and the resonant circuit 2 is formed by connecting a capacitor circuit in series to a coil L2. The capacitor circuit is constructed by connecting two capacitors C2 and 03 in the lk column, and the switching element 21 is connected to the capacitor C3.
(for example, semiconductor switching elements) are connected in series.

The data to be transmitted is stored in memory 23. The control circuit 22 reads data from the memory 23.

The signal is converted into a serial signal SD, and the switching element 21 is turned on and off using this signal SD. Data reading is performed in synchronization with the clock signal C output from the divide-by-9 circuit 26.

The memory 23 is preferably a non-volatile memory.

For example, electrically rewritable EEPROM (IEIe
ctrlcally [Erasable Progr.
aa+mable ReadOnly Memory
) is preferably used, and if the data is read out in parallel, a P/S (parallel/serial) conversion circuit is provided in the control circuit 22, and if the data is read out in serial, the control circuit 22 is provided with a P/S (parallel/serial) conversion circuit. The circuit 22 may be of any type as long as it drives the switching element 21 according to the read code.

When coil Ll and Lz are inductively coupled, coil L
The signal E appearing at 2 is input to the frequency dividing circuit 2G. A clock signal C is generated by dividing the frequency of this signal E at an appropriate ratio and shaping the waveform.

The level detection circuit 25 detects the level of the signal E appearing in the resonant circuit 2. This level detection circuit 25 is connected to the device 10.
The degree of coupling between the two coils L and Lz in a device that transmits signals when either of the devices IO and 20 move and the devices IO and 20 approach each other! It is effectively used to detect When the level detection circuit 25 detects that the signal E exceeds a certain level v1, an operation command V is given to the divide-by-1 circuit 25 and the control circuit 22.

The switching element 21 of the resonant circuit 2 is serially controlled to turn on and off depending on each bit constituting the data to be transmitted. The control signal SD of the switching element 21, the value of each bit of data (1 or 0), and the state (on or off) of the switching element 21 are shown in FIG. FIG. 5 also shows other output signal waveforms of the circuit of FIG. Clock signal C is a frequency-divided signal E, so when the frequency of signal E changes, the frequency of clock signal C also changes, but in FIG. 5 it is represented as a constant frequency. ing. The output V of the level detection circuit 25 is expressed as a state in which the transmitting device 20 approaches the receiving device 10, as will be described later.

When the switching element 21 is off, the resonant circuit 2 is L.
It becomes a series resonant circuit of 2 and 02, and the resonance is given by that.

When the switching element 21 is on, the resonant circuit 2 forms a series resonant circuit of L and (Cl1C3), and its resonant frequency f3 is.

It is given by f −1/[2π(L (C+C))1/2].

On the other hand, in the receiving device 10, one oscillation circuit 1 has a coil L
The oscillation frequency [1 is set to a value different from the above-mentioned resonance frequencies f and f. Therefore, when the coil L2 of the resonant circuit 2 is close to the coil L1 of the oscillation circuit 1 and inductively coupled to each other, the effective inductance of one oscillation coil changes, so that the oscillation frequency becomes f
A frequency deviation of ±ΔF is given. This frequency deviation amount differs depending on when the switching cable 21 is on and when it is off, and the oscillation frequency of the oscillation circuit 1 when it is off is c
When it is on, it is expressed by fl3 and is 12 degrees. The state of this frequency shift is shown in FIG. 5 as an oscillation signal (output signal) A of the oscillation circuit 1.

The period of signal A in FIG. 5, like the period of signal E induced in coil L2, is drawn considerably expanded compared to the period of signal SD.

Although the loss resistance of the oscillation coil increases as described above due to the coupling between the coils Ll and L2, the two-oscillation circuit 1 is constructed so that the oscillation state can be sufficiently maintained despite this increase in loss.

Output A of the oscillation circuit 1 is sent to a frequency demodulation circuit 13.

This circuit 13 is, for example, F S K (FrequCn
cySllirt Keying) circuit consists of 1
The modulated signal R is extracted from the oscillation output A. This signal R is applied to the switching element 2 as shown in FIG.
1 represents the on/off state, that is, the data stored in the memory 23.

FIG. 6 shows the transmitting device 20 moving (in the moving direction of arrow Y1 in FIG. 2) and facing the receiving device 10. In this way, when either the transmitting device 20 or the receiving device 10 moves and the second device 20 approaches, the operation of the device shown in FIG. 4 is as follows. At time t-To, nine coils L and L2 are inductively coupled to each other.
0 and 10 are not close. As device 20 moves closer to device 10, fills L2 and Ll begin to combine;
A voltage signal E is induced in the coil L2 of the resonant circuit 2 by the oscillation of the oscillation circuit 10, and this is detected by the level detection circuit 25. When the detection level V exceeds a certain threshold v1 (time t-T1), the frequency dividing circuit 2B and the control circuit 22 start operating. The frequency dividing circuit 2B is the control circuit 22
Since the control circuit 22 supplies the clock signal C to the memory 23, the control circuit 22 reads out the data in the memory 23 and controls the on/off state of the switching element 21 based on the data. The on/off state of the switching element 21 is determined by the demodulation circuit 1 on the device IO side.
3 is detected as described above.

In the above embodiment, it may be f-f or fl-f3.

In the above embodiment, the capacitors C and C in the capacitor circuit of the resonant circuit 2 are switched by the switching cable 21, but in the same way as the principle diagram shown in FIG. 1 or as shown in FIG. , the resonant circuit may be opened and closed.

Further, by providing 2 or more switching elements, 2 or more J-
By switching the resonant circuit connection, it becomes possible to transmit not only binary information but also multivalued 6 information, and even in the case of binary information, more than 2 bits of information can be sent and received at once. It becomes like this.

Furthermore, as shown in FIGS. 8 and 9.

As a means for changing the effective inductance of the oscillation coil of the oscillation circuit, it is also possible to change the sharpness Q (-ωL/R) of the resonant circuit. Figures 8 and 9
In the figure, the connection of the resistor R is switched by turning the switching cable 21 on and off.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram for explaining the principle of information transmission. FIG. 2 shows the arrangement of the transmitting and receiving devices, and FIG. 3 is a sectional view showing two coils that are inductively coupled. FIG. 4 is a circuit diagram showing the electrical configuration of a signal transmission device showing an embodiment of the present invention, FIG. 5 is a waveform diagram showing its operation, and FIG. 6 is a diagram showing how the transmitting device and receiving device approach each other. It is. 7 to 9 are circuit diagrams showing modified examples of the resonant circuit. 1...Oscillation circuit, 2...Resonance circuit. IO...Receiving device, 13...FMuL adjustment circuit. 20... Transmitting device, 21... Switching element. 22... Control circuit, 23... Memory. 2B... Frequency divider circuit, L, L...
coil. Patent applicant X'1 Ishidenki Co., Ltd. 11th representative
Patent attorney Ken Ushiku (1 person) Figure 1 Figure 2 Figure M3 Figure 2 δ 10 Old) Figure 4 Figure 5 Figure 6 (A) t=T, (B) t=T; Figure 7 Figure 8 Figure 9

Claims (3)

[Claims] (1) A transmitter comprising a resonant circuit including a switching element and a coil that switches a resonance state, a memory that stores data, and a control circuit that controls the switching element according to data read from the memory, and the resonant circuit. A signal transmission device comprising: an oscillation circuit including a coil capable of electromagnetic induction coupling with a coil; and a receiving device equipped with a demodulation circuit that detects changes in the output of the oscillation circuit. (2) The signal transmission device according to claim (1), wherein the memory is a nonvolatile memory. (3) The transmitter is provided with a frequency dividing circuit that divides the frequency of the signal induced in the coil of the resonant circuit and outputs a clock signal, and this clock signal is used as a timing signal for reading data from the memory. A signal transmission device according to claim 1, which is used as a signal transmission device.