JPH04315680A - Radio type code signal transmitting device - Google Patents

Abstract

PURPOSE:To provide a small radio type code signal transmitting device by directly exciting the code signal with the frequency corresponding to the output of a code signal generation section. CONSTITUTION:When a switch 16 is turned on, a transistor 20 is turned on, a base current is fed to a transistor 20 for a fixed period, the transistor 20 is turned on, and power is fed to an elastic surface wave resonant circuit 13 for a fixed period. A code signal generating circuit 12 feeds the code signal read from a signal memory circuit 11 to the elastic surface wave resonant circuit 13. The elastic surface wave resonant circuit 13 generates the excitation output of the frequency corresponding to the level of the output of the code signal generating circuit 12, an RF amplifying circuit 14 amplifies the excitation output of the elastic surface wave resonant circuit 13 and transmits radio waves from a transmitting antenna 15.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmitting device, and more particularly to a small wireless code signal transmitting device that can be used in a remote control device such as a wireless lock device.

0002

2. Description of the Related Art As disclosed in Japanese Unexamined Patent Publication No. 63-44089, a wireless door lock control device using a small and low-capacity power source is known. This wireless door lock control device includes a code signal generation section that generates a predetermined code signal, a high frequency oscillation section that oscillates at a predetermined frequency, and an output of the high frequency oscillation section that generates a predetermined code signal. a modulation section that modulates;
The transmitter includes a harmonic component resonator that resonates with a predetermined harmonic component of an oscillation frequency of the high frequency oscillation section, and a transmitting antenna connected to the harmonic component resonator. The code signal generator generates a predetermined code.
The high frequency oscillation section generates an oscillation output of a predetermined frequency, and the output is modulated by the modulation section in accordance with the code signal from the code signal generation section. The output of the high frequency oscillation section modulated according to the code signal is input to the harmonic component resonance section. The harmonic component resonance section is configured to resonate at a predetermined harmonic among the harmonic components included in the output of the high frequency oscillation section. The harmonic components resonated in the harmonic component resonator are transmitted from the transmission antenna of the harmonic component resonator. In this wireless door lock control device, a CMOS type IC is used to generate high frequency waves in order to downsize the transmitter.

0003

[Problems to be Solved by the Invention] In the conventional transmitter described above, a code signal is superimposed on the oscillation output of the crystal oscillator to change the load capacity of the crystal oscillator, and the frequency of the output is oscillated up to the short wave band. ing. For this reason, conventional transmitters require a crystal resonator and an oscillation inverter, resulting in an increased number of components. In addition, by changing the load capacity of the crystal oscillator,
Since the frequency of the output is oscillated in a short wave band, specific harmonic components such as the third harmonic component must be extracted as output. Therefore, the characteristics of each element must be precisely adjusted. Furthermore, since it is constructed from a one-chip monolithic CMOSIC, a resonant circuit is required to oscillate once to a frequency level of 21 MHz and then further multiply the frequency to 63 MHz, which makes the entire circuit complicated. In other words, in the past, multiple stages of circuitry including an oscillation circuit were required, which resulted in larger equipment and
This causes an increase in the number of parts and an increase in product defect rates and malfunctions. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a compact wireless code signal transmitter that can directly excite at a frequency corresponding to the output level of a code signal generator.

0004

[Means for Solving the Problems] A wireless code signal transmitting device according to the present invention includes a signal storage circuit for storing code signals and a code signal for reading out the code signals stored in the signal storage circuit. a surface acoustic wave resonant circuit that generates an excitation output of a frequency corresponding to the output level of the code signal generation circuit; and a surface acoustic wave resonant circuit that amplifies the excitation output of the surface acoustic wave resonant circuit and transmits radio waves from a transmitting antenna. It consists of an RF amplifier circuit for transmitting data. The surface acoustic wave resonant circuit has one comb-shaped electrode connected to the code signal generation circuit via a capacitor, and the other comb-shaped electrode that generates an excitation output that is excited in response to the voltage level applied to the one comb-shaped electrode. It has a surface wave resonator made of a comb-shaped electrode, and an oscillation circuit connected to the other comb-shaped electrode and sending an output to an RF amplifier circuit. A resistor is connected between the code signal generation circuit and the surface acoustic wave resonant circuit,
A non-linear capacitive element is connected between the resistor and the surface acoustic wave resonant circuit. A coil and a capacitor are connected in series between the nonlinear capacitive element and one comb-shaped electrode. The code signal generation circuit includes a switching element that supplies power to the surface acoustic wave resonant circuit for a certain period of time when the switch is turned on.

[0005]

[Operation] When the switch of the code signal generation circuit is turned on,
The switching element is turned on, and power is supplied to the surface acoustic wave resonant circuit for a certain period of time. Here, the code signal generation circuit supplies the code signal read from the signal storage circuit to the surface acoustic wave resonant circuit. The surface acoustic wave resonant circuit generates an excitation output with a frequency corresponding to the output level of the code signal generation circuit, and the RF amplifier circuit amplifies the excitation output of the surface acoustic wave resonant circuit and transmits radio waves from the transmitting antenna. . At this time, when a voltage is applied to one comb-shaped electrode of the surface acoustic wave resonant circuit, a strain is generated between it and the other comb-shaped electrode due to the piezoelectric effect, and a surface wave is excited. Therefore, the surface acoustic wave resonant circuit generates an excitation output at a frequency level corresponding to the level of the applied voltage. In this way, direct excitation can be performed at a frequency corresponding to the output level of the code signal generation circuit without requiring a plurality of stages of oscillation circuits.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wireless code signal transmitting apparatus according to the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a block diagram schematically showing a wireless code signal transmitting apparatus according to the present invention. A wireless code signal transmitter 10 according to the present invention includes a signal storage circuit 11 for storing code signals.
, a code signal generation circuit 12 that reads out the code signal stored in the signal storage circuit 11, and a surface acoustic wave that generates an excitation output of a frequency corresponding to the level of the output of the code signal generation circuit 12. It is composed of a resonant circuit 13 and an RF amplification circuit 14 that amplifies the excitation output of the surface acoustic wave resonant circuit 13 and transmits radio waves from the transmitting antenna 15. The code signal generation circuit 12 is connected to a power source 17 via a switch 16, and the surface acoustic wave resonant circuit 13 and the RF amplifier circuit 14 are connected to the switch 16 and a transistor 2 as a switching element.
0 to the power supply 17. The base of transistor 20 is connected to the output terminal of code signal generating circuit 12. Further, the code signal generation circuit 12 and the surface acoustic wave resonant circuit 13 are connected via a resistor 18, and a variable capacitance diode as a non-linear capacitive element is connected between the resistor 18 and the surface acoustic wave resonant circuit 13. 19 cathodes are connected. The anode of variable capacitance diode 19 is grounded. In the above configuration, when the switch 16 is turned on, a base current is supplied from the code signal generation circuit 12 to the transistor 20 for a certain period of time, the transistor 20 is turned on, and power is supplied to the surface acoustic wave resonant circuit 13 for a certain period of time. be done. Here, the code
The code signal generation circuit 12 supplies the code signal read from the signal storage circuit 11 to the surface acoustic wave resonance circuit 13. The surface acoustic wave resonant circuit 13 generates an excitation output with a frequency corresponding to the level of the output of the code signal generation circuit 12, and the RF amplifier circuit 14 amplifies the excitation output of the surface acoustic wave resonant circuit 13 and transmits it to the transmitting antenna 15. Send radio waves from.

FIG. 2 is a circuit diagram showing details of the wireless code signal transmitting apparatus according to the present invention schematically shown in FIG. An input terminal 12a of a code signal generating circuit 12 constituted by a one-chip microcomputer is connected to a positive terminal of a power supply 17. An input terminal 12b of the code signal generating circuit 12 constituting a reset terminal is connected to the positive terminal of a power supply 17 via a series circuit of a switch 16 and a capacitor 31. The input terminal 12c of the code signal generation circuit 12 is connected to the power supply 1.
Connected to the negative terminal of 7. A resistor 30 is connected between the connection point between the switch 16 and the capacitor 31 and the negative terminal of the power supply 17.
The input terminals 12b and 12c are connected by a resistor 32. A resistor 33 that determines an oscillation constant is connected to the input terminals 12d and 12e. Output terminal 12f
is connected to the base of transistor 20 via resistor 34. The emitter of transistor 20 is connected to the positive terminal of power supply 17. The collector of the transistor 20 is connected to a drive circuit 21, a surface acoustic wave resonance circuit 13, and an RF amplifier circuit 14.
It is connected to the. An input terminal 12g of the code signal generating circuit 12 is connected to the base of a transistor 40 of the drive circuit 21 via a resistor 35. Code signal generation circuit 1
The two input terminals 12h, 12i and 12j are connected to the signal storage circuit 11. Transistor 4 of drive circuit 21
The base and emitter of 0 are grounded through resistors 41 and 42, respectively. The collector of the transistor 40 is a resistor 43
It is connected to the collector of transistor 20 via. Further, the collector of the transistor 40 is connected to one comb-shaped electrode 24a of the surface acoustic wave resonator 24 of the surface acoustic wave resonant circuit 13 via the resistor 18, coil 22, and capacitor 23 connected in series. Coil 22 and capacitor 23 are used to adjust the oscillation frequency. The other comb-shaped electrode 24b of the surface acoustic wave resonator 24 is connected to the base of a transistor 26 via a capacitor 25. Drive circuit 21
A voltage dividing circuit consisting of resistors 44 and 45 is provided. The cathode of variable capacitance diode 19 is connected between resistor 18 and coil 22, and the anode of variable capacitance diode 19 is grounded via capacitor 46. Although not shown in detail, one comb-shaped electrode 24a of the surface wave resonator 24
The other comb-shaped electrode 24b is formed on a grounded piezoelectric substrate in order to excite and receive surface waves, and the surface wave resonator 24 has a four-terminal structure. When a voltage is applied to one comb-shaped electrode 24a of the surface acoustic wave resonant circuit 13, distortion is generated between it and the other comb-shaped electrode 24b due to the piezoelectric effect, and a surface wave is excited. Therefore, the surface acoustic wave resonant circuit 13 generates an excitation output at a frequency level corresponding to the level of the voltage applied to one comb-shaped electrode 24a. transistor 26
Resistors 47 and 48 forming a voltage dividing circuit are connected to the base of the circuit. Further, the base and emitter of the transistor 26 are connected by a capacitor 50. Transistor 26 and capacitor 50 constitute an oscillation circuit 27 similar to a Colpitts oscillation circuit. The collector of transistor 26 is connected to the collector of transistor 20, and the emitter is connected to resistor 5.
1 to ground. The emitter of transistor 26 is connected via capacitor 52 to the base of transistor 60 constituting RF amplifier circuit 14. Further, the base of the transistor 60 is connected to the resistors 61 and 62 forming a voltage dividing circuit.
connected to. The collector of transistor 60 is connected to the collector of transistor 20 via LC circuit 63 and to the transmitting antenna 15 via capacitor 64. The LC circuit 63 is necessary to improve the S/N ratio and to match the impedance of the antenna 15. The emitter of the transistor 60 is a resistor 6 connected in parallel.
5 and a capacitor 66.

In the above configuration, when the switch 16 is pressed, a reset pulse is applied from the power supply 17 to the input terminal 12b of the code signal generating circuit 12 via the capacitor 31. As a result, the code signal generation circuit 12
is applied to the base of the transistor 40 of the drive circuit 21,
As a result, the code signal read from the signal storage circuit 11 is supplied to the surface acoustic wave resonant circuit 13. At the same time, a low-level output is supplied from the output terminal 12f of the code signal generation circuit 12 to the base of the transistor 20 for a certain period of time, so that the power is supplied from the power supply 17 to the drive circuit 21 and the surface acoustic wave resonant circuit via the transistor 20. 13 and the RF amplifier circuit 14 are supplied with power. Therefore, the surface acoustic wave resonant circuit 13
generates an excitation output with a frequency corresponding to the output level of the code signal generation circuit 12, and the RF amplifier circuit 14 amplifies the excitation output of the surface acoustic wave resonant circuit 13 via the Colpitts oscillation circuit 27 and transmits the output from the transmitting antenna. Transmit radio waves from 15. In this manner, in this embodiment, direct excitation can be performed at a frequency corresponding to the level of the output of the code signal generating circuit 12 without requiring a plurality of stages of oscillation circuits.

[0009]

[Effects of the Invention] In the present invention, as described above, direct excitation can be performed at a frequency corresponding to the output level of the code signal generation circuit 12 without requiring a multi-stage amplifier circuit including an oscillation circuit. A compact wireless code signal transmitter can be obtained with a reduced number of parts. Moreover, in this invention, the inverter
This method has the advantage that it does not require the use of a controller or a circuit for extracting harmonic components.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing a wireless code signal transmitting device according to the present invention.

[Fig. 2] A circuit diagram showing details of the wireless code signal transmitting device according to the present invention.

[Explanation of symbols]

10. ．． Wireless code signal transmitter, 11. ．． Signal storage circuit, 12. ．． Code signal generation circuit, 13. ．． Surface acoustic wave resonant circuit, 14. ．． RF amplifier circuit, 15. ．． transmitting antenna, 16. ．． switch, 17. ．． Power supply, 18. ．． Resistance, 19. ．． Variable capacitance diode (non-linear capacitance element), 2
0. ．． Transistor (switching element), 22. ．． Coil, 23. ．． capacitor

Claims (5)

[Claims] Claims 1: A signal storage circuit that stores a code signal; a code signal generation circuit that reads out the code signal stored in the signal storage circuit; A wireless system comprising a surface acoustic wave resonant circuit that generates an excitation output of a corresponding frequency, and an RF amplification circuit that amplifies the excitation output of the surface acoustic wave resonant circuit and transmits radio waves from a transmitting antenna. Code signal transmitter. 2. The surface acoustic wave resonant circuit has one comb-shaped electrode connected to the code signal generation circuit via a capacitor and an excitation output that is excited in accordance with the level of voltage applied to the one comb-shaped electrode. A wireless code signal according to claim 1, comprising: a surface wave resonator formed of the other comb-shaped electrode that generates a waveform; and an oscillation circuit connected to the other comb-shaped electrode and sending an output to an RF amplifier circuit. Transmitting device. Claim 3: A resistor is connected between the code signal generating circuit and the surface acoustic wave resonant circuit, and a non-linear capacitive element is connected between the resistor and the surface acoustic wave resonant circuit. A wireless code signal transmitting device according to . 4. The wireless code signal transmitting device according to claim 3, wherein a coil and a capacitor are connected in series between the nonlinear capacitive element and one comb-shaped electrode. 5. The wireless code according to claim 1, wherein the code signal generation circuit includes a switching element that supplies power to the surface acoustic wave resonant circuit for a certain period of time when the switch is turned on.
signal transmitter.