JPH0453082Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a transmission control circuit that controls transmission of a modulated signal output from a modulation circuit.

[Conventional technology]

This type of transmission control circuit is applied, for example, to a device that displays when a specific person, such as a manager, enters or leaves an office in a building. FIG. 5 shows such a room entry/exit display device, and in the figure, 5 is a display device for displaying entry/exit, and 6 is door open detection means for detecting the opening of an entrance-only door and an exit-only door, each of which is dedicated to the entrance. It is composed of detection means 60 and 61 for the door and the exit-only door. Reference numeral 7 indicates an open signal output means for outputting a door open signal based on the output of the detection means 6, and 8 indicates a personal data signal unique to the specific person in response to the door open signal from the open signal output means 7, which is owned by a specific person. A personal data signal output means 9 receives personal data and identifies a specific person from the data signal; 10 inputs the output of the door opening detection means 6 and the identification signal of the identification means 9 to identify the person; This is a display driving means that turns on and off the display means 5 corresponding to the person.

In the above configuration, when a predetermined person enters the room, the opening detection means 60 on the entrance door side detects this by opening the entrance-only door. The open signal output means 7 is actuated by this detection signal and outputs a door open signal. Personal data signal output means 8 possessed by a predetermined person receives this door open signal and sends out a unique personal data signal, and the identification means 9 identifies the personal data. Then, the display driving means 1
0 is driven and the display means 1 corresponds to a predetermined person.
lights up or goes out.

On the other hand, when the predetermined person exits the room, a detection signal is output from the opening detection means 61 on the exit door side by opening the exit door. The open signal output means 7 is activated by this detection signal and outputs a door open signal. Thereafter, personal data is sent out from the personal data signal output means 8 in the same manner as when entering the room, the personal data is identified by the identification means 9, and is inputted to the display driving means 6 together with the detection output of the opening detection means 61. The display driving means 10 turns off or lights up the display means 5 corresponding to a predetermined person in response to input of each of these signals.

Through the above operations, entry and exit of a predetermined person can be identified.

The personal data signal output means 8 in FIG. 5 is equipped with an oscillation circuit for generating a carrier, and a blocking oscillation circuit shown in FIG. 3 has been conventionally used as the oscillation circuit. In the figure, the base of transistor _Q3 is connected to the primary side of blocking transformer T, and is connected to bias power supply _VB through a parallel circuit of resistor _R6 and capacitor _C4 . Further, the collector of the transistor _Q3 is connected to the transmission switch _SW1 through the secondary side of the blocking transformer T, and further connected to the power supply Vcc.

In such a configuration, when transmitter switch SW ₁ is turned on and collector current flows through transistor Q ₃ ,
The blocking transformer T increases the base voltage, further increasing the collector current. As a result, the collector current further intensifies the rise in the base current, causing rapid oscillation. However, the increase in base voltage stops when base current starts flowing,
At the same time, the collector current also stops increasing. Therefore, the voltage on the primary side (base side) of the blocking transformer T goes in the opposite direction and changes rapidly in the opposite direction. Therefore, the collector current decreases rapidly, and this change continues until the collector current becomes zero. Therefore, the AM oscillation ends in approximately half a cycle, and since the base voltage is positive, the base current does not flow and becomes a large value, charging the capacitor _C4 . This once charged charge is discharged through resistor _R6 , and no collector current flows and oscillation does not occur until the base voltage reaches the cutoff voltage. Furthermore, when the base voltage reaches the cutoff voltage, the plate current begins to flow and oscillation occurs again. By repeating the above operations, the collector output continues to be an AM oscillation output as shown in FIG. 4a.

On the receiving side, this oscillation output is envelope-detected and demodulated by an integrating circuit to demodulate the DC signal shown in FIG. 4b.

[Problems to be solved by the invention] When using such a conventional blocking oscillation circuit, the oscillation output has the waveform shown in Figure 4a, and when this is demodulated, it becomes a direct current as shown in Figure 4b. The number of components is smaller than that of a rectangular wave with the same time length.
Therefore, an integral amplifier circuit for demodulation is required on the receiving side, which causes a delay in operation and may result in failure to respond when the moving speed of the moving object is high.

[Means for solving problems]

The present invention was developed in view of the conventional problems as described above, and includes a monostable multivibrator driven by a transmission switch in a transmission control circuit that controls the transmission of a modulated signal output from a modulation circuit.
an output control circuit that stops the output of the monostable multivibrator for a predetermined period of time when the output from the monostable multivibrator stops, regardless of the state of the drive switch; and a modulation circuit that modulates the output of the monostable multivibrator using the output of the monostable multivibrator. A modulated signal sending circuit that sends out a signal is provided.

[Effect]

In the above configuration, when the transmitter switch is operated, a monostable multivibrator (hereinafter referred to as OSM) is activated.
is driven, and the OSM sends out an output signal for a certain period of time. The modulated signal sending circuit receives this signal and causes the modulating circuit to send out the modulated signal for a certain period of time. On the other hand, when the output from the OSM stops, the output control circuit detects this stopped state and causes the OSM to stop outputting its output for a predetermined period of time regardless of the operation of the transmission switch. As a result, even if the transmitter switch chattering or the switch is operated abnormally fast,
OSM can always send out a square wave with a fixed length of time.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a resistor _R1 and a transmission switch _SW1 are connected in series between a power supply Vcc (for example, DC +5V) and ground, and the connection point thereof is input to the SOM1 via a capacitor _C1 and a resistor _R2 . The OSM1 includes a NAND circuit NAND ₁ , a capacitor C ₂ , a resistor R ₃ , and a variable resistor
Consists of VR ₁ and NAND circuit NAND ₂ , resistor
The output of R ₂ is input to the NAND circuit NAND ₂ , and the output thereof is input to the NAND circuit NAND ₂ via a series circuit of a capacitor C ₂ and a resistor R ₃ . A variable resistor VR ₁ is connected between the connection point of the series circuit and ground. Also, the output of the NAND circuit NAND ₂ is a NAND circuit
The output of the NAND circuit NAND ₂ , which is input to NAND 1 and is the output of OSM ₁ , is input to output control circuit 2. The output control circuit 2 is composed of a variable resistor VR ₂ , a capacitor C ₃ , a diode D ₁ , an inverter INV ₁ , and a NAND circuit NAND ₃ .
The output of NAND ₂ is input to inverter INV ₁ via variable resistor VR ₂ and is grounded via diode D ₁ and capacitor C ₃ connected in series.
The connection point is also connected to the slider of variable resistor _VR2 . NAND circuit NAND ₂ and inverter INV ₁
The outputs of each are input to the NAND circuit NAND ₃ , and the output thereof is input to the NAND circuit NAND ₂ . Also, the output of the NAND circuit NAND ₂ is sent to the modulation signal sending circuit 3.
is input. The sending circuit 3 is composed of a PNP transistor Q ₁ and resistors R ₄ and R ₅ , and is a NAND circuit.
The output of NAND ₂ is connected to transistor Q ₁ through resistor R ₄
The emitter is connected to the power supply Vcc, and a bias resistor _R5 is connected between the emitter and the base. The collector of transistor Q ₁ is supplied to a modulation circuit 4 . The modulation circuit 4 includes a Hartley-type oscillation circuit composed of a transistor Q ₂ and the like, and is supplied with a power supply Vcc via the transistor Q ₁ . Further, the modulated signal is sent out from the antenna ANT.

The operation of such a configuration will be explained with reference to the waveform diagrams of each part shown in FIGS. 2a to 2g. 1st
Symbols a to g in the figure correspond to the waveforms a to g in FIG. 2, respectively. In the initial state when the transmitting switch SW ₁ is off, one input of the NAND circuit NAND ₁ is at H level (power supply voltage Vcc level) as shown in FIG. 2a, and the resistor R ₃ of the NAND circuit NAND ₂
Since the input on the side is at L level as shown in b in the same figure, its output is at H level as shown in c in the same figure. Therefore, since the H level is applied to the base of the transistor _Q1 , the transistor _Q1 is turned off and no modulation signal is output. Further, since the other input of the NAND circuit NAND ₁ (the output of the NAND circuit NAND ₂ ) is at the H level as described above, its output is at the L level. Furthermore, since the output of the NAND circuit NAND ₂ is at the H level, the output of the inverter INV ₁ is at the L level as shown in e of the figure, and therefore the NAND circuit
The output of NAND ₃ is at H level as shown in f in the figure.

Here, when the transmitting switch SW ₁ is turned on at time t ₁ , the input on the resistor R ₂ side of the NAND circuit NAND ₁ goes to L level as shown in Figure 2 a, and its output goes to H.
level. Therefore, the output of the H level is shown in figure b.
The time constant of capacitor C ₂ and variable resistor VR ₁ as
It is differentiated by C ₂ ·VR ₁ , and the differentiated output is applied to the input on the resistor R ₃ side of the NAND circuit NAND ₂ .
Therefore, for a certain period of time until the differential output drops to the threshold level of the NAND circuit NAND ₂ , the time T ₁ NAND ₂
The output of is inverted to L level as shown in c of the figure. Since this L level output is applied to the base of transistor Q ₁ , transistor Q ₁ is turned on for a period of T ₁ , and the oscillation circuit is driven, as shown in g of the same figure.
A modulated signal is sent from ANT. The L level output of this NAND circuit NAND ₂ is the NAND circuit NAND _3.
and is applied to diode _D1 , so the charging voltage of capacitor _C3 is instantly discharged.
Therefore, the input of the inverter _LNV1 becomes L level at approximately time _t1 as shown in d in the figure, and its output becomes H level as shown in e in the same figure. Yotsute Nando circuit
Since the output of NAND ₃ continues to be at the H level even after time t ₁ , the output remains at the L level for the time T ₁ when the input on the resistor R ₃ side of the NAND circuit NAND ₂ is at the H level. , the modulation circuit 4 is continuously driven.

The input on the resistor R ₃ side of the NAND circuit NAND ₂ is the time constant
C ₂ ·VR ₁ , and when it drops to the threshold level at time t ₂ as shown in FIG. 2b, the output is again inverted to the H level as shown in FIG. 2c. Therefore, this H level is applied to the base of the transistor _Q1 , turning off the transistor _Q1 , cutting off the power supply to the modulation circuit 4, and stopping the transmission of the modulation signal as shown in g of the figure. In addition, the input of inverter INV ₁ is connected to capacitor C ₃ and variable resistor VR ₂ as shown in d in the same figure.
During the period T ₂ during which the voltage rises according to the time constant C ₃ ·VR ₂ and reaches the threshold level of the inverter INV ₂ , the output is at the H level as shown in the figure e. Therefore, since both of the two inputs of the NAND circuit NAND ₃ are at H level, its output is at L level during period T ₂ as shown in FIG. Therefore, even if the OSM1 is driven by chattering or an abnormally fast operation of the transmitting switch _SW1 during this period, and the input on the resistor _R3 side of the NAND circuit _NAND1 becomes H level, its output will be as shown in c in the figure. Maintain the H level.

Time constant C ₃ , VR ₂ which is the input of inverter INV ₁
When the signal rises sufficiently and reaches the threshold level at time _t3 , the output of inverter INV ₁ is inverted to L level as shown in e of the figure, and the output of NAND circuit NAND ₃ is inverted to H level as shown in f of the same figure. . Therefore, the circuit shown in FIG. 1 returns to the above-mentioned initial state, and by turning on the transmission switch _SW1 again, the above-described operation is repeated to drive the modulation circuit 4 for a certain period of time _{T1 and} send out a modulation signal. Furthermore, the time constants C ₁ and R 1 of the capacitor C ₁ and the resistor _{R 1 can} also be used to prevent chattering or high-speed movement of a moving object by delaying the input of the NAND circuit NAND ₁ when the transmitting switch SW ₁ is off. The circuit 4 is prevented from being driven.

〔effect〕

As described above, according to the present invention, since the DC component of the oscillation output is larger than that of a blocking oscillation circuit,
A simple integrating circuit may be provided on the receiving side to demodulate this signal. Therefore, there is no delay in operation,
For example, when an oscillation output is sent from a moving body, the receiving side can sufficiently respond to the moving speed of the moving body. Further, it is possible to forcibly send out a modulated signal of a certain length of time in response to chattering of a transmitting switch, etc.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the transmission control circuit according to the present invention, Fig. 2 a to g are timing charts showing signal waveforms of each part in Fig. 1, and Fig. 3 shows a conventional transmission control circuit. Circuit diagram, Figure 4 ab
3 is a signal waveform diagram of each part in FIG. 3, and FIG. 5 is a block diagram showing a room entry/exit display device to which the present invention and the conventional transmission control circuit are applied. 1... Monostable multivibrator, 2... Output control circuit, 3... Modulation signal sending circuit, 4... Modulation circuit, SW ₁ ... Transmission switch.

Claims (1)

[Scope of Claim for Utility Model Registration] In a transmission control circuit that controls the transmission of a modulated signal output from a modulation circuit, a monostable multivibrator driven by a transmission switch, and a predetermined device that when the output from the monostable multivibrator stops, an output control circuit that stops the output of the monostable multivibrator regardless of the state of a drive switch; and a modulation signal sending circuit that causes the modulation circuit to send out a modulation signal using the output of the monostable multivibrator. Characteristic transmission control circuit.