JPH0363257B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is characterized in that the transmission frequency is n times the source oscillation frequency (n
The present invention relates to a wireless notification device having a transmitter configuration of =2,3,4...).

[Technical Background of the Invention] As shown in Fig. 3, a wireless notification device transmits a security signal, a gas leak detection signal, a fire alarm signal, etc. based on the output of a sensor to the notification device itself using a wireless transmitter. is configured to transmit to a wireless receiver.

Conventionally, the technology in this field was
There were those described in Nos. 60-67469 and 60-67470. Hereinafter, its general configuration will be explained using figures.

FIG. 4 is a block diagram showing an example of the configuration of a transmitter of a conventional wireless notification device. In the figure, 1 is an input terminal that receives a notification signal from an external sensor means, etc. This signal is input to a pulse data generation circuit 3, and this pulse data generation circuit 3 generates a clock signal of a crystal oscillation circuit 2 as a source oscillation circuit. Based on this, when the notification signal is received, the determined pulse code data is output. The switching circuit 4 receives the output pulse data signal from the pulse data generating circuit 3, changes the bias of the next stage crystal oscillation circuit 5, and controls its oscillation operation on and off. Under the control of the switching circuit 4, the crystal oscillation circuit 5 applies an output signal with an oscillation frequency _XT2 to the next-stage frequency conversion circuit 6 during oscillation, and this frequency conversion circuit 6 multiplies the signal by n (n=2, 3). , 4 . . . ) and gives a signal with an output frequency of n· _XT2 to the next stage amplifier circuit 7, and the amplified signal is radiated into the air via the antenna circuit 8. Note that 9 is a battery that energizes the entire circuit element.

FIG. 5 is a schematic diagram of a receiver corresponding to the transmitter of the reporting device of FIG. 4. This receiver is configured and operates in substantially the same manner as a general broadcasting receiver, and is placed close to the main body of the reporting device that provides housing information and the like. In the figure, 20 is a receiving antenna;
A radio wave carrying transfer information from the transmitting antenna 8 is received and applied to a high frequency amplification circuit 21, and the signal amplified here is converted into an intermediate frequency signal by a local oscillation circuit 23 and a frequency mixing circuit 22. After the signal is amplified by the intermediate frequency amplification circuit 24,
AM detection is performed through the AM detection circuit 25. The configuration and operation up to this point are the same as a general receiver.
After that, this AM detection signal is shaped into a square wave by the waveform shaping circuit 26, and the pulse data demodulation circuit 27
sent to. This pulse data demodulation circuit 27 is configured to compare the input pulse data signal with predetermined pulse data and send an output signal to the output terminal 31 when they match.

Here, the operation of the reporting device configured as described above will be explained.

FIG. 6 shows the operation timing of the transmitter of the above-mentioned conventional device. When no notification signal is input to input terminal 1 of the transmitter, that is, when there is no security signal, etc. (for example, the input is in the "L" state)
The output of the pulse data generation circuit 3 is in the "H" state,
Therefore, the base of the switching transistor _Q2 of the switching circuit 4 becomes high and does not conduct, and no bias current is applied to the oscillation transistor 2 of the crystal oscillation circuit 5 at the next stage, so that oscillation is stopped. On the other hand, when there is a notification signal input to the input terminal (for example, input "H" state), pulse data is output from the output of the pulse data generation circuit 3.
When this output is in the "L" state (b in the figure), a bias current is passed through the oscillation transistor _Q2 of the crystal oscillator circuit 5, and the circuit 5 oscillates at a frequency determined by the crystal oscillator XT2 (Fig. c). This oscillation output is frequency-converted by the frequency conversion circuit 6 to give an output frequency n· _XT2 (n=2, 3...) (d in the figure), which is amplified by the amplifier circuit 7 and received as a radio wave from the antenna circuit 8. sent to the machine.

However, since conventional wireless devices are configured as described above, a frequency conversion circuit is required in the transmitter to convert the oscillation frequency of the crystal oscillation circuit to the transmission frequency, and the circuit is complex and has a large number of parts. Therefore, there were drawbacks such as increased costs.

[Object of the Invention] In view of such circumstances, the present invention has been developed to increase the oscillation frequency of a crystal oscillation circuit as a source oscillator by n times (n=2, 3,
It is an object of the present invention to provide a wireless notification device that has high frequency stability, has a simple circuit, and is inexpensive by obtaining a transmission frequency of 4...).

[Summary of the Invention] In order to achieve the above object, the present invention provides a wireless notification device that transmits a security signal based on a sensor output to the main body of the notification device using a wireless transmitter at an appropriate transmission frequency. a source oscillation circuit, an oscillation circuit that oscillates at a frequency close to the transmission frequency, a gate means for transmitting the output of the source oscillation circuit to a subsequent stage based on the security signal, and an output signal of the gate means to transmit the output of the source oscillation circuit to the next stage. and switching means for controlling the on/off operation of the source oscillation circuit, thereby obtaining a transmission frequency n times (n=2, 3, 4...) the oscillation frequency of the source oscillation circuit.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a transmitter of a wireless notification device according to the present invention. 1st
In the figure, the same elements as those in FIG. 4 are given the same reference numerals.

The difference between the wireless notification device of this embodiment and the conventional device shown in FIG. 4 is that when the output pulse data signal of the pulse data generation circuit 3 is in the "H" state, A gate-operated NAND circuit 10 is inserted to transmit the output signal of the crystal oscillator circuit 2 to the next-stage switching circuit 11.
A switching circuit 11 that controls on/off of the oscillation operation of the next stage LC oscillation circuit 12 by the output signal of the NAND circuit 10 is inserted in place of the conventional switching circuit 4, and the next stage is a conventional crystal oscillation circuit. The LC oscillation circuit 12, which oscillates at a frequency near the transmission frequency, is inserted in place of the oscillation circuit 5.
Here, the LC oscillation circuit 12 as a single circuit, that is, the switching transistor Q ₅ of the switching circuit 11 is in an off state, and the oscillation transistor Q ₆ of this circuit 12 is normally biased and oscillates continuously. Let the oscillation frequency be ₀ * when the

Further, the receiver has exactly the same configuration as the conventional one shown in FIG. 5, and is not shown here.

Next, the operation of the transmitter of the wireless notification device configured as described above will be explained below with reference to the timing diagram of FIG.

As shown in FIG. 2, when there is no notification signal input to the input terminal 1 (for example, the input is in the "L" state), the output of the pulse data generation circuit 3 is in the "L" state.
Since the output of the NAND circuit 10 is in the "H" state, the switching transistor _Q5 of the switching circuit 11 is in the on state, and the emitter potential of the oscillation transistor _Q6 of the LC oscillation circuit 12 rises. Since it is in a reverse bias state, oscillation has stopped.

Next, when there is a notification signal input to the input terminal 1 (for example, input "H" state), the determined pulse data is output from the output of the pulse data generation circuit 3 (b in the figure), and the output is " When in the "H" state, the oscillation output signal of the crystal oscillation circuit 2 as a source oscillator passes through the NAND circuit 10 (a in the figure) and is output in an inverted form (c in the figure). That is, when the output of the pulse data generation circuit 3 (b in the figure) and the output of the crystal oscillation circuit 2 (a in the figure) are both in the "H" state, the output of the NAND circuit 10 is in the "L" state (in the figure). c) At this time, the switching transistor _Q5 of the switching circuit 11 is turned off, and the LC oscillation circuit 12
The oscillating transistor _Q6 is normally biased,
It enters an oscillation state (d in the figure).

In the circuit configured as above, LC
The oscillation frequency ₀ of the oscillation circuit 12 oscillates at n times the oscillation frequency _XT of the crystal oscillation circuit 2 (n=2, 3, 4...). That is, ₀ = n・_XT (≠ ₀ *) However, ₀ is the oscillation frequency of the LC oscillation circuit 12, _XT
is the oscillation frequency of the crystal oscillation circuit 2, ₀ * is the oscillation frequency of the LC oscillation circuit 12 alone, n = 2, 3, 4...
...is...

Note that although the above embodiment uses a crystal oscillator XT as the source oscillator, any other oscillation element such as a ceramic oscillator may be used, and any circuit system may be used. .

Similarly, the circuit system of the LC oscillation circuit 12 may be any circuit system such as CR oscillation.

Furthermore, the switching circuit 11 may be of any circuit type as long as it can similarly control on/off of the oscillation of the oscillation circuit 12 at the next stage.

Further, although the output in this embodiment is of a wireless type emitted from an antenna, the same effects as in the above embodiment can be obtained even if the output format is a wired type.

As described above, according to the present invention, the oscillation frequency of the crystal oscillation circuit is multiplied by n (n=2,
In order to obtain the transmission frequency of 3, 4...), the structure is constructed without a frequency conversion circuit, so the circuit is simple and the number of parts is reduced, which has the effect of reducing the cost of the device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the transmitter of the wireless notification device according to the present invention, FIG. 2 is an operation timing diagram of the transmitter of the present invention shown in FIG. 1, and FIG. 4 is a block diagram of a conventional transmitter, FIG. 5 is a block diagram showing a receiver of a conventional wireless notification device, and FIG. 6 is a general diagram of a wireless notification device. 4 is an operation timing diagram of the transmitter of the conventional notification device shown in FIG. 4. FIG. 2... Crystal oscillation circuit, 3... Pulse data generation circuit, 7... Amplification circuit, 8... Tentenna circuit, 9
...Battery, 10...NAND circuit, 11...Switching circuit, 12...Oscillation circuit, 25...AM
Detection circuit, 26... Waveform shaping circuit, 27... Pulse data demodulation circuit.

Claims (1)

[Claims] In a wireless notification device that transmits a security signal based on a sensor output to the notification device main body side using a wireless transmitter at an appropriate transmission frequency, the wireless transmitter includes a source oscillation circuit and an oscillation circuit that oscillates at a frequency close to the transmission frequency. and a gate means for transmitting the output of the source oscillation circuit to a subsequent stage when the security signal is present, and a switching means for controlling the on/off operation of the oscillation circuit at the next stage by the output signal of the gate means, A wireless notification device characterized in that a transmission frequency n times (n=2, 3, 4...) the oscillation frequency of the source oscillation circuit is thereby obtained.