KR860002032B1 - A radio receiver - Google Patents

Abstract

In an emergency, regular broadcasting is cancelled and the Civil Defence Head office sends out urgent broadcastings. Anytime, radio was turn off though, it is possible to turn it on by a special signal of Head office. Therefore we can listen to the contingency broadcasting. The parts of our interest in the broadcast receiver are composed of receiving a make and break signal generating demodulation circuit and signal generating transmitter. Especially the latter is connected to switch between Amp. signal of Head office and Voice mixer and switch make and break signal generator.

Description

Broadcast receiver with civil defense alarm automatic receiver

The accompanying drawings show an embodiment of the present invention.

1 is a schematic diagram of an emergency alarm generator receiver.

2 is a schematic diagram of a receiving switch switch signal generation demodulation circuit of the present invention.

3 is a schematic diagram of a transmission open / close signal generator according to the present invention.

4 is an operation timing diagram of a transmission open / close signal generator.

5 is a bandpass frequency characteristic diagram.

6 is an analysis timing diagram of the malfunction occurrence prevention function.

7 is a timing diagram of a reception open / close signal generation demodulation circuit.

8 is a block diagram of an existing alarm apparatus on the transmitting side.

9 is a block diagram of a transmission switch signal generating device of the present invention.

10 is an operation timing diagram of the present invention.

The present invention relates to a broadcast receiver having a civil defense alert automatic reception device, so that the emergency broadcast of the headquarters can be immediately heard at any time in an emergency.

Normally, when a general broadcast is interrupted in an emergency and the emergency broadcast of the Civil Defense Headquarters is heard, existing radio receivers are not allowed to listen to the emergency broadcast only when the radio receiver is continuously listening to it with the radio "on". It is possible, but for example, if you do not turn on the radio, you can not listen to the emergency broadcast even if there is a radio receiver in a closed building or in a relatively closed area. Even in an actual emergency, various problems were caused.

In view of the above drawbacks, the present invention is designed to listen to emergency broadcasts by switching the radio to “on” when only a certain tone is sent from the emergency broadcasting headquarters even when the radio is not turned on. For example, based on the accompanying drawings, it is as follows.

In the emergency alarm generator receiver,

In detection, the band-pass filter (f ₂ ) and the level comparator 2 are connected in series to the amplification stage, and the input is connected to one logic AND gate 4, and the band-filter (f ₂ ) and the level comparator 1 are connected in series to the amplifier stage. It becomes the input terminal to the logic AND gate 4, and connects the monostable multi-delay circuit from the input of the level comparator 1 and the monostable multi 3 in series to take another logic AND gate 4 input terminal and takes the logic AND gate, and A signal to a receive / open signal generation demodulation circuit and a PTT switch connected to a flip-flop circuit 6 by taking an input terminal having an on-off switch, an output terminal of a logic AND gate 4, a logic OR gate 5, and connecting the flip-flop circuit 6 to an open / closed signal; The output stage from the monostable multi 1 and the logic OR gate 2 are connected, and the output terminal is directly connected to the monostable multi 2 through the negative logic circuit 1. A switch 1 is formed between the azimuth headquarter amplifier signal and the voice mixer, and another output terminal is connected to the voice mixer through an open / close signal generator and connected to the switching switch input coral, and connected to the negative logic circuit 2 from the PTT switch. The stable multi 1 is connected to the negative logic circuit 2 from the PTT2 switch, and the input terminal and logic OR gate 1 are connected to the transmission signal generator circuit connected to apply the switching switch drive signal.

Referring to the effect of the present invention configured in this way in detail as follows. First of all, the accompanying drawings show an embodiment of the present invention. FIG. 1 is an emergency alarm apparatus, which is divided into a high frequency part and a low frequency part, and a variable local oscillation circuit operates during manual operation to listen to general radio or broadcast. When the manual operation switch is returned to the automatic position, the variable station oscillation circuit stops operation and the modified control local oscillation circuit is operated to receive the broadcast of the civil defense headquarters.

2 is a schematic diagram of a reception switch signal generation demodulation circuit according to the present invention;

3 is a system diagram of a transmission open / close signal generator of the present invention,

4 is a timing PTT switch, A point PTT, which is a monostable multi 2, that is, a monostable multi 2, that is, a switching signal is driven, and a bar is a switching switch driving.

5 is a frequency characteristic diagram of a bandpass filter,

6 is an analysis timing diagram of a malfunction generator; A is an output of level comparator 1, B is an output of level comparator 2, C is an output of a monostable multi delay circuit, D is an output of a monostable multi 3, E is the output of AND gate 4.

7 is a timing diagram of the receiving open / close signal generation demodulation circuit, where A is the output of level comparator 1, B is the output of 2 of level comparator, C is the output of monostable multi-delay circuit, and D is monostable. The output of the multi 3, E is the output of the AND gate 4, F is the output of the flip-flop 6.

In addition, the open / close signal generator circuit of the present invention may select a digital circuit such as dual tone multi frequency (DTMT) double tone, multi-frequency method, FSK method, PCM method, etc., but is not limited thereto. In order to explain the circuit, the DTMT method will be described as an example.

On the other hand, in the present invention, the configuration of the PTT switch is composed of a 4 × 4 matrix (that is, 16 buttons) using a key button, and the designated signal can be selected at a desired time at a desired time.

In FIG. 3, when the PTT (Press to talk) switch is activated (or pressed), the monostable multi 2 operates first to generate a pulse of 100 ms-200 ms (configurable), which emits a double tone. The generated pulse is switched by the negative logic circuit 1 so that the signal from the microphone is cut off.

When the monostable multi 2 pulse enters via negative logic 1, how the position 1 is opened, the pulse is generated by the integrated circuit MC144 ₁₀ and the PTT switch composed of 4 × 4 matrix, which is the logic OR gate 2 and The pulse is generated in the negative logic circuit 1 and the switch 1 is driven by the relay. When the PTT switch is released, 2 becomes 0 by the negative logic circuit, so that the monostable multi 1 is operated, and the output of the mono stable multi 1 operates the mono stable multi 2 by the OR logic gate 2.

More specifically, how OR gate 2 operates single-precision multi 2 is pulsed by the PTT switch and integrated circuit MC144 ₁₀ and connected to logic OR gate 2 through negative logic 2 and monostable multi 1 in FIG. The logic OR gate 2 is operated.

As a result, even when the PTT switch is released, the switching signal generating circuit is operated for the same period as when the PTT switch is pressed to emit double sound.

The pulse that generated the double tone is directly input to the logic OR gate 2 from the PTT switch, and another pulse is input to the logic OR gate 2 by a delayed signal, that is, a signal operated by the negative logic circuit 2 and the monostable multi 1. It drives monostable multi 2 and passes 1 to the negative logic circuit to drive switch 1 by the relay switch. In the open / close signal generator, switch 1 is driven by the switch relay. During operation, a double sound is generated by the switching signal generator itself. One of them is inputted to the mixer as a switch 1 ion through a negative logic circuit, and another sound is directly input to the voice mixer.

The logical OR gate 1 logically adds the period of pressing the PTT switch and the period of the monostable multi 1 to operate the switching switch until an open / close signal is sent.

In the present invention, the use of the DTMF method is one of methods for preventing malfunctions. However, when a dual tone is used, there is almost no distribution of such simultaneous sounds in a voice or a film. In addition, even if there is such a double tone state, the pulse timing time is different so that malfunction can be distinguished.

Therefore, in the present invention, the above-described method is very easy because the method can be easily implemented by modulating the voice frequency without modifying the broadcasting station transmitter.

Prior to describing the operation of the emergency alarm generator receiver in the present invention, the features of the present invention for the receiving axis are advantages of manufacturing a receiver for automatic emergency alarm generation using a general super heterodyne receiver and only opening and closing. Although a signal generation demodulation circuit adapter may be added, some modifications are inevitable when applied to an existing receiver. In the present invention, a modified control oscillation method is adopted in a local oscillation circuit to stably receive a certain station frequency.

When adopting the crystal oscillation method in the local oscillation circuit, how the frequency of certain broadcasting station is stabilized, there are various oscillation methods for driving any system such as heart lane oscillation, Colpitts oscillation, crystal oscillation, etc. Among them, the crystal oscillation method with the best frequency stability was selected. When this is used, the frequency stability is good, so the switch operation is accurate, so the station frequency is stable.

In FIG. 1, the high frequency part of the receiver is always operated, and the power consumption rate is designed to be very low, so there is no problem with the power supply, and power consumption is usually consumed at the low frequency part.

The reason for the low power consumption is that the integrated circuits (MC144 ₁₀ and MC14528), in which the intrinsic characteristics of the integrated circuits consume very little power, are used, so the power consumption of the transmitter and receiver is very low.

Therefore, it is configured to open and close the low frequency (called muting) by the automatic switching signal detected at the high frequency, and the high frequency power supply allows the use of a rechargeable ghermet-type secondary gun.

In addition, when the high frequency unit detects the open / close signal, as shown in FIG. 1, the signal transmitted to the transmission shaft passes through the antenna unit on the receiving side, passes through the high frequency medium frequency medium width detection, and is input to the open / close signal demodulation circuit. The pulse generated by the signal sent from the transmitting side drives the switch open / close signal.

In addition, how the open / close signal opens the low frequency part, the open / close signal (double tone) sent to the transmitting side passes through the high frequency part of FIG. 1 and the open / close signal demodulation circuit (FIG. 2), and the relay switch (switch open / close circuit). As a result, the open / close signal on the transmission side is amplified and transmitted to the low frequency unit.

Referring now to the operation of the emergency alarm generator receiver again, as shown in Figure 1 is a system driven by the open and close signal demodulation circuit is added to the rear end of the high-frequency section of the receiver, Figure 2 is to explain the open and close signal demodulation circuit It is a block diagram. In other words, when a specified signal (dual tone) enters the receiver, the passive amplifies the designated signal (dual tone) as shown in the figure even if the receiver is turned off by the -off switch, and thus the level filter and the level comparator of f ₁ , f ₂ . The logic AND gate is driven by the monostable multi-delay circuit and the monostable multi-delay circuit passed and delayed by the oscillator, and the logical OR gate 5 is formed by this signal. (Switch switching circuit of Fig.) Is operated so that the signal sent to the transmitting side in the emergency can automatically receive the emergency signal through the low frequency section on the receiving side.

On the other hand, the operation of the open / close signal generation demodulation circuit in the present invention, as shown in Fig. 2, the logic AND gate by the amplification filter, the level comparator and the stage stable multi-delay circuit, the monostable multi 3 as shown in FIG. Drive 4 to operate the logic OR gate 5 to go through the T flip-flop circuit 6 to activate the switching relay (i.e. switch switching circuit) to receive the signal sent to the transmitting side through the high frequency section and the low frequency section of the receiving side. In this case, the opening / closing signal generation receives the signal sent from the transmitting side and delivers the delay and the signal.

In addition, the double sound of the audio signal detected by the high frequency unit is amplified once and passed through a bandpass filter (band pass filter). More specifically, as shown in the frequency characteristics of the band filter of FIG. 5, the low pass filter and the high pass filter are combined to pass only the AC component of the frequency in the passband frequency range, so that only the output is not passed.

The bandpass filter uses a microfork or tuning fork by a tuning fork, an op amp, or a PLL method.

The single note passing through the band filters 10 and 11 is compared by the level comparator 1 and 2 and reduced to the original pulse (100ms-200ms).

The pulse obtained from the level comparator 1 is applied to the logic AND gate 4, and is applied to the monostable multi-delay circuit to be delayed to 500ms-100ms to operate the monostable multi 3 to generate a pulse having a pulse width of 500ms-100ms.

It is ANDed at the level comparator 1 and level comparator 2 and logic AND gates to prevent malfunctions caused by the same single tone that may occur in music voices or sirens.

The principle of this operation is the same as the timing diagram of the open / close signal generation double circuit of FIG. 7, and the generated open / close signal operates the T flip-flop circuit 6 of FIG. 2 once, so that the first signal sets the flip-flop and the second signal flip-flop. The circuit 6 is reset, and the logic OR gate 5 is used to manually set and reset the flip-flop circuit 6.

The output of the flip-flop circuit 6 opens and closes a switch connecting the detected voice output to the low frequency part, and in this principle, the high frequency part can generate an automatic emergency alarm.

As described above, the present invention is a practical invention in which the transmitter can listen to emergency broadcasts at any place by automatically turning on the power switch according to a specified frequency even if the transmitter transmits a constant tone by the PTT switch in the emergency. .

Claims (1)

In the emergency alarm generator receiver, in the detection, the band filter f ₂ and the level comparator 2 are connected in series to the amplification stage, and are input to one logical AND gate 4, and the band filter f ₁ and level comparator are connected to the amplification stage. Serial 1 is connected to another logic AND gate 4, and the monostable multi delay circuit from the input of level comparator 1 and monostable multi 3 are connected in series to form another logic AND gate 4 input terminal. Receiving switch signal generation demodulation connected to apply the open / closed signal by taking the gate, the input terminal with the ground terminal and the manual on-off switch, the output terminal of the logic AND gate 4, the logic OR gate 5, and the 7 flip-flop circuit 6 Take the signal from the low and PTT switch, take the output from the monostable multi 1 and the logic OR gate 2, and connect the output to the mono stable multi 2 in series The output terminal is connected to the civil defense headquarters amplifier signal and the voice mixer through the negative logic circuit 1, and the other output terminal is connected to the voice mixer through the open / close signal generator to the switching switch input signal, and the negative logic at the PTT switch. And the transmission signal generator circuit connected to the monostable multi 1 through circuit 2 and the input terminal and logic gate 1 from the PTT switch to apply to the switching switch driving signal. Broadcast receiver with civil defense alarm automatic receiver.

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