KR100427042B1 - Wireless broadcasting system - Google Patents

Abstract

PURPOSE: A wireless broadcasting system is provided to reliably and conveniently broadcast by using an amplifier and a walkie talkie for broadcast of a village. CONSTITUTION: A receiver receives signals transmitted from a walkie talkie(S200). Strength of the received signals is measured(S205). It is confirmed whether a preliminarily decided carrier frequency is identical to a carrier frequency of the signal transmitted from the walkie talkie(S210). It is confirmed whether combination of the corresponding frequency and a CTCSS(Continuous Tone Coded Squelch System) or CDCSS(Continuous Digital Coded Squelch System) signal is accurate(S215). It is confirmed whether a DTMF(Dual Tone Multi Frequency) code is identical to a preliminarily set code and a receiving time gap of the DTMF code is measured(S220,S225). An amplifier is turned on(S230). A sound for notifying start of a broadcast is broadcasted and the broadcast goes on air(S217,S219). A signal interruption time is confirmed(S240). If a new DTMF code is inputted while the broadcast is on air, it is confirmed that the DTMF code is identical to the designated DTMF code(S245). A termination signal sound is outputted and the amplifier is turned off(S255).

Description

Wireless Broadcasting System

The present invention relates to a type of wireless microphone system for short range broadcasting, and more particularly, to a short range broadcasting amplifier system capable of wirelessly broadcasting by using a radio in a frequency band of a general life radio. It is about.

In general, unlike urban areas, rural areas and mountainous areas are areas where communication is vulnerable, and local communities are equipped with amplifiers and speakers installed in public facilities due to the need for disaster warning or administrative broadcasting. to be. These amplifiers and speakers are called village amplifiers.

The village amplifier is a device that transmits information through broadcasting to villagers. It consists of an amplifier to amplify the voice, a speaker, and a microphone to convert the voice signal into an electrical signal.

Conventional village amplifiers have been inconvenient to use because they had to go to the village hall and turn on the amplifiers and broadcast them using a wired microphone when broadcasting and installing amplifiers and speakers in a village common facility such as a village hall. . The installation location of the amplifier is also restricted because the person who wants to broadcast should go to the place where the amplifier is located and turn on and use the amplifier. In addition, there is a problem that a quick broadcast in the event of an emergency disaster situation, etc., there was a problem that anyone can easily access the village amplifier.

The present invention has been made to solve the problems caused during the broadcast of various conventional disaster prevention as described above,

Rather than a conventional wired microphone, the present invention relates to a village amplifier system using a wireless microphone that wirelessly connects a microphone and an amplifier. In general, commercially available wireless microphones are expensive and have no countermeasures in frequency crosstalk. In the case of a wireless microphone, the microphone user is not informed about the same frequency usage. In addition, the output is 10 mW is weaker in terms of outdoor applications than the life radio proposed in the present invention.

SUMMARY OF THE INVENTION An object of the present invention is to provide a village amplifier system using a walkie-talkie, which can be prevented by providing a reliable and rapid disaster alert or administrative broadcast in advance to the local people while overcoming the disadvantages of the conventional wired microphone.

Village amplifier system of the present invention for achieving the above object is a radio for outputting a radio frequency, a receiver for receiving a signal transmitted from the radio, amplifies the signal received from the receiver and generates a voice signal to output to the speaker A broadcast amplifier, an amplifier control device for controlling the broadcast amplifier according to the signal received from the receiver and a speaker for outputting the audio signal.

Since the radios and receivers used in the present invention use the public frequencies of the domestic radios, there is a need for connection security procedures for randomly received frequencies and countermeasures against noises for signals of the same frequency introduced during use.

For the security procedure of connection, the radio transmits CTCSS or CDCSS tone or DTMF signal at the transmission frequency and the receiver checks it, that is, it can only broadcast if it passes the security procedure for some kind of broadcasting. Allows control of the power supply. For the noise of the same frequency signal, measure the intensity of the radio wave received from the receiver, that is, the intensity of radio wave of the designated wireless microphone used in the area of the village amplifier. Configure the circuit so that it does not receive.

1a is a schematic diagram of the overall system of the invention

1B is a schematic diagram of a radio transmission system of the present invention

1C is a schematic diagram of a receiving system of a receiver of the present invention;

2A is a flowchart of a security procedure for wireless broadcasting according to an embodiment of the present invention.

Figure 2b is a transmission signal used in an embodiment of the present invention

3A is a flowchart of a security procedure for wireless broadcasting according to another embodiment of the present invention.

3b is an output signal used in another embodiment of the present invention

Figure 4 is a circuit diagram of the attenuator and detector of the receiver device of the present invention

*** Explanation of symbols for the main parts of the drawing ***

10: radio 20: receiver

30: amplifier control device 40: broadcast amplifier

50: speaker 101: microphone

103, 155, 161: AF amplifier 105: HPF

107: analog bilateral filter 109: Pre Emphasis Circuit

111: AF amplifier limiter 113: Deviation adjustment stage

115: programmable attenuator 117: modulator

119 digital controller 121 DTMF encoder

123: CTCSS tone control stage 125: CTCSS IC

151: Speaker 153: AF Power Amplifier

157: programmable attenuator 159: analog bilateral switch

163: De-Emphasis circuit 165: CTCSS IC HPF

167: demodulator 171: DTMF decoder

400: antenna 403: band selection filter

405: Detector 407: Low Noise Amplifier

410: digital controller 415: attenuator

420: Image reject filter 425, 460: RF DOWN mixer

430: RF local oscillator 440: channel selection filter

445: IF amplifier 450: PLL

455: IF local oscillator

When described in detail with the accompanying drawings, preferred embodiments of the present invention according to the technical spirit as described above are as follows.

1 is a schematic diagram of a village amplifier system using the radio of the present invention.

According to the drawings, the present invention receives the radio 10 used as a wireless microphone for broadcasting wirelessly, receives the signal transmitted from the radio 10 and outputs the received data signal to the amplifier control device and the audio signal to the broadcast amplifier A receiver 20 for outputting, an amplifier control device 30 for controlling a broadcast amplifier according to the received signal, a broadcast amplifier 40 for amplifying and outputting a voice signal output from the receiver to a predetermined level, and outputting from the receiver It is composed of an amplifier controller for controlling the broadcast amplifier by receiving the received data signal and the speaker 50 for outputting the voice.

Since the radio used in the present invention uses a UHF band (448 MHz), which is the same frequency band as a general life radio, it uses a published frequency, and thus a signal transmitted from an unwanted radio is transmitted to the broadcast amplifier 40. Security procedures are in place to prevent access.

1B and 1C illustrate a system configuration for transmitting and receiving a DTMF, CTCSS or CDCSS code of the household radio of the present invention. FIG. 1B shows a configuration diagram of a system for transmitting a DTMF code and a CTCSS or CDCSS code in a configuration installed at a transmitting end of a living radio. 1c shows a schematic diagram of a system for receiving DTMF code signals or CTCSS or CDCSS code signals included in the received signals and analyzing the signals.

An embodiment of a method of using and terminating a broadcast in a receiver of a village amplifier system using the living radio will be described. The security procedure of the wireless broadcast according to the embodiment of the present invention is described with reference to FIG. 2A.

To broadcast using a village amplifier, turn on the radio's microphone and occupy the frequency to be used. When a radio push-to-talk (PTT) button is pressed, a continuous tone coded squelch system (CTCSS) or continuous digital coded squelch system (CDCSS) signal f1 is transmitted together with a specified carrier frequency F1. After a predetermined time when the signal is sent out, preferably about one second later, the DTMF signal is sent out.

The signal transmitted from the radio is shown in FIG. 2B.

The receiver receives the carrier frequency, the CTCSS or CDCSS signal transmitted from the radio, and a DTMF signal transmitted after a predetermined time. The receiver uses the carrier frequency, the CTCSS or CDCSS signal, and the DTMF signal as an access security signal for use and termination of the amplifier. The receiver analyzes the received signal through the steps shown in FIG. 2B and permits the amplifier to broadcast through a security procedure for using the amplifier. This procedure is described below with reference to FIG. 2B.

Receiving a signal transmitted from the radio (S200); The receiver receives the carrier frequency, CTCSS or CDCSS signal and DTMF signal transmitted from the radio by turning on the radio and pressing the PTT button.

Checking a signal received at the receiver (S205); By measuring the strength of the signal received at the antenna of the receiver and checking whether it is possible to receive it, reception is blocked when the signal strength is below a certain level.

Checking a carrier frequency (S210); It checks whether the predetermined carrier frequency and the carrier frequency of the signal transmitted from the transceiver are the same between the radio and the receiver, and blocks the reception of the signal if it is not the same frequency.

Checking the CTCSS or CDCSS signal (S215); Since a wireless micro-radio is used, the CTCSS or CDCSS signal is transmitted together with the specified frequency, so that the combination of the corresponding frequency and the CTCSS or CDCSS signal is correct at the reception. If not, the receiving circuit does not receive the frequency. Here, CTCSS is to be used when only two people communicate with each other with a preset tone code without being disturbed by other people. to be.

Checking the DTMF code and signal time interval (S220, S225); After the first reception of the CTCSS or CDCSS tone signal, a code signal of a 5-digit DTMF coded in advance is received at a time of about 1 second. At this time, the receiver checks whether the DTMF code is the same as the predetermined code. The reception time interval of the DTMF code is measured to determine whether the time is within a predetermined time.

Turning on the amplifier (S230); The amplifier controller determines whether to receive a signal based on a combination of a frequency received from a receiver and a CTCSS tone, the DTMF code, the first reception time of the CTCSS tone, and a reception time of the DTMF within a predetermined time (1000 ms) (S111). Done. When all of the signals match, the broadcast amplifier is turned on.

Broadcasting (S217) and broadcasting (S219) a sound informing the start of broadcasting; When the amplifier control device completes all of the above confirmation procedures, it turns on the power of the broadcasting amplifier and outputs a signal such as a chime through the amplifier to announce that it is ready for broadcasting, and outputs the received voice signal for broadcasting. do.

Checking the signal blocking time (S240); The signal received by the receiver is continuously measured to see if there is a signal received, preferably for at least 5 seconds, for a predetermined time.

DTMF code checking step (S245); If a DTMF code is input while the broadcast is in progress, check whether it is the same as the designated DTMF code.

Outputting an end signal and powering off the amplifier (S255); While the broadcast is in progress, when the signal is cut off for a predetermined time, preferably 5 seconds or more, or when the predetermined DTMF code is input, a signal sound for notifying the end of the broadcast is broadcast and the power of the amplifier is turned off.

3a illustrates another embodiment of a method of using and terminating a broadcast in a receiver of a village amplifier system using the living radio.

A confirmation procedure for security of a wireless broadcast according to the other embodiment of the present invention is described.

To broadcast using a mind amplifier, turn on the radio's microphone and occupy the frequency to be used. When a radio push-to-talk (PTT) button is pressed, a continuous tone coded squelch system (CTCSS) or continuous digital coded squelch system (CDCSS) signal f1 is transmitted together with a specified carrier frequency F1. In the transmission of the tone code, three tones are continuously transmitted at intervals of 1 second according to the contents previously input.

The signal transmitted from the radio is shown in Figure 3b.

The receiver receives the carrier frequency and the CTCSS or CDCSS signal transmitted from the radio. The receiver uses the carrier frequency and three different CTCSS or CDCSS signals as an access security signal for use and termination of the amplifier. The receiver analyzes the received signal through the steps shown in FIG. 3A and permits the amplifier to broadcast through a security check for use of the amplifier. This procedure is described below with reference to FIG. 3A.

Receiving a signal transmitted from the radio (S300); The transceiver is powered on and the PTT button is pressed to receive a carrier frequency, CTCSS or CDCSS signal at the transceiver.

Checking a signal received at a receiver (S305); By measuring the strength of the signal received at the antenna of the receiver and checking whether it is possible to receive it, reception is blocked when the signal strength is below a certain level.

Checking a carrier frequency (S310); Check if the carrier frequency sent from the radio is the same, and block the reception of the signal if it is not the same frequency.

Checking the CTCSS or CDCSS signal (S315, 320, 325); Since a wireless micro-radio is used, the CTCSS or CDCSS signal is transmitted together with the specified frequency, so that the combination of the corresponding frequency and the CTCSS or CDCSS signal is correct at the reception. If not, the receiving circuit does not receive the frequency. In this embodiment, three signals are continuously received at one-second intervals to check whether the tone code for each is the same as a predetermined code. The signals are Tone1, Tone2 and Tone3, which are three predetermined signals of FIG. 3B, which are tone signals for user security.

Turning on the amplifier (S330); The amplifier controller determines whether to receive a signal based on whether the frequency received from the receiver and the three CTCSS tone codes match. When all of the signals match, the broadcast amplifier is turned on.

Broadcasting a sound for notifying the start of broadcasting and starting broadcasting (S335); When the amplifier control device completes all of the above confirmation procedures, it turns on the power of the broadcasting amplifier and outputs a signal such as a chime through the amplifier to announce that it is ready for broadcasting, and outputs the received voice signal for broadcasting. do.

Checking the signal blocking time (S340); The signal received by the receiver is continuously measured to see if there is a signal received, preferably for at least 5 seconds, for a predetermined time.

Terminating CTCSS or CDCSS code checking step (S345); If a CTCSS or CDCSS code signal for a predetermined termination is input while the broadcast is in progress, it is checked whether the same as the designated CTCSS or CDCSS code. In the present embodiment, the fourth CTCSS code signal corresponds to Tone4 of FIG. 3A.

Outputting an end signal and powering off the amplifier (S350); While the broadcast is in progress, the signal is cut off for a predetermined time, preferably 5 seconds or more, or when the predetermined CTCSS or CDCSS code is input, a signal sounding to end the broadcast is broadcast and the power of the amplifier is turned off.

In order to minimize the interference on the same frequency that may be introduced into the amplifier during broadcasting of the present invention, the reception sensitivity of the amplifier side is adjusted to maintain the minimum reception sensitivity level, so even if the same weak signal is not received by the receiver itself. Do not recognize it as a level. Since the radio used in the present invention is used at a short distance, it will be used within a radius of about 500 m mainly because it is inside the village. Therefore, by measuring the location of the heart amplifier and the location of the radio used in the field, the minimum electric field strength in the area of use is measured, and attenuators are installed in the radio receiver at the amplifier so that the signal weaker than the electric field strength can be cut off. Adjust reception sensitivity. The attenuation range of the attenuator is adjusted in 5 steps at 10dB intervals to allow a total of 50dB adjustment. The attenuator is operated automatically, and the attenuator is adjusted by setting the receiving limit as the level of the input signal within 10 hours plus a margin value of 10 dB. Therefore, the circuit is configured not to receive a signal whose signal level is below a certain level.

5 is a diagram illustrating a system configuration of the emergency alarm wireless receiver attenuator and detector.

In FIG. 5, the detector 505 is a device for measuring the intensity of the radio wave received from the antenna and transmitting it to the controller. The attenuator 515 is a device that weakens the received signal itself to analyze the strength of the signal sensed by the detector to prevent the inflow of the system inherently a signal below the appropriate signal to receive the signal received from the radio. That is, if the receiver's reception sensitivity (lowest level that can be received) is -120 dBm and the minimum level of the radio being used is -90 dBm, the level of the attenuator is increased by 30 dBm to cut off signals below the level of the radio currently in use. do.

Preferably, the wireless receiver of the mind amplifier of the present invention is designed to be used only by users of living radios within a radius of up to 500 meters. Thus, signals coming from areas outside the use radius are designed to be blocked at their source. Therefore, Free Space Loss, that is, the propagation loss reference value between transmitting and receiving antennas in the visible range, that is, the loss of the radio wave until the output of the transmitting radio reaches the receiver of the emergency alarm, is calculated as follows. .

For a distance of 500 meters (D) at a frequency of 448 MHz (F), the free space loss (F.L.S.) is calculated as

F.S.L. (dB) = 32.4 + 20 log F (Frequency: 448MHz) + 20 Log D (Distance: 0.5Km) = 79.4 dB

The transmit power is 27 dBm for 500mW and the transmit / receive antenna gain is 0 dB. Therefore, the received power is calculated as follows.

Received power = 27 dBm (transmit power)-79.4 dBm (loss) + 0 (transmit antenna gain) + 0 (receive antenna gain) = -52.4 dBm

In addition, considering the building transmission loss (10 dBm), fading (fading loss) (10 dBm) and the village receiver receiver sensitivity (-116 dBm) as a correction condition, the reception margin is as follows.

Receive Margin = 116dBm-52.4dBm-10dBm -10dBm = 43.6 dBm

Most transmit signals have a margin of 43.6 dBm at the village amplifier receiver. If we assume that the change in sensitivity to the movement, movement, and position of the radio user is assumed to be 10 dB, then the receiver's receive sensitivity should be up to -82.4 dBm. Therefore, the reception level reference value is -82.4 dBm, and the attenuator adjustment level is 50 dB / 10 dB in five stages. If the receiver sensitivity is -116 dBm, the reception sensitivity drops to -66 dBm under the highest attenuation conditions.

When the attenuator is used, as described above, the receiver sensitivity of the receiver is -116 dBm, and the sensitivity required when using the 500m visible distance is -82.4 dBm considering the margin as in the above equation. Therefore, if the attenuator is adjusted by three stages and attenuated by -30 dBm and received by the receiver, the unwanted frequency level of the living radio used outside the 500m distance is expected to be lower than the living radio in use, thereby preventing jamming.

The detector checks the receiving sensitivity every 5 seconds from the start time of the radio used. Here, a margin (10 dBm prediction value) is added to the lowest received sensitivity to be determined as a reference value of the reception level. Based on the reference value, the attenuator can be operated to block the low level of the same signal as the frequency being used to prevent interference.

In the present invention, since the amplifier is operated unattended, the power is automatically turned on during broadcasting for the input power management of the amplifier, and the power is automatically cut off when the broadcasting ends. The power of the amplifier is normally turned off, but the amplifier control unit can turn on or off the amplifier depending on the signal received from the receiver. When the broadcast end signal is received or no radio signal is received, the amplifier control unit may automatically turn off the amplifier. In normal use, always turn on the receiver and amplifier controls.

The radio can be broadcast using a village amplifier wirelessly, so it can be reliably and conveniently broadcasted. Lee and Dong, who broadcast a lot in the village or region, can keep the radio for the broadcast and broadcast it wherever they want.

Since the radio is used as a wireless microphone, there is no restriction on the use of radio waves, there is no cost to use the radio wave, and the 500 mW output is used, which makes it easier to use because the reach is longer than that of the 10 mW of the wireless microphone.

In addition, the present invention can economically and reliably and promptly broadcast the desired information to a specific area, there is an effect that can deliver alerts and administrative information about the disaster to the public.

Claims (5)

In the short-range wireless broadcasting system using a living radio, A receiver for receiving a signal transmitted from a radio; A broadcast amplifier receiving the signal received from the receiver and amplifying the signal; An amplifier controller for controlling the broadcast amplifier according to a signal received from the receiver; And The speaker outputs a voice signal from the signal output from the broadcast amplifier, The amplifier controller performs a security procedure using a carrier frequency and a signal such as a CTCSS or CDCSS tone signal or a DTMF received from the radio, and controls the power of the broadcast amplifier according to the result of the security procedure. Village amplifier system using a radio. The method of claim 1, The receiver includes a detector for sensing the strength of the received signal and an attenuator for attenuating the input signal, The village amplifier system using the radio, characterized in that the reception of the signal is cut off if the strength of the received signal is below a certain intensity. In the short-range wireless broadcasting system using a living radio, The radio transmits a signal for a security procedure including a voice signal, The signal includes a carrier frequency and transmits at least one signal of a predetermined CTCSS or CDCSS signal or a DTMF code, The village amplifier system using a radio, characterized in that used as a confirmation signal for a security procedure for the access control of the wireless broadcasting system including a receiver, an amplifier control device, a broadcasting amplifier and a speaker for receiving the transmitted signal. The method according to any one of claims 1 to 3, The security procedure Checking whether the carrier frequency transmitted from the radio is the same frequency as a predetermined frequency; Checking whether the combination of the CTCSS or CDCSS signal received together with the carrier frequency is equal to a predetermined signal, Receiving a 5-digit DTMF code coded in advance after receiving the CTCSS or CDCSS signal, and confirming whether the DTMF code is the same as a predetermined code; Measuring a time interval between reception of the CTCSS or CDCSS signal and the DTMF code to determine whether the time is within a predetermined time; When the amplifier controller determines whether the combination of the carrier frequency received from the receiver and the CTCSS or CDCSS signal, the DTMF code and the first reception time of the CTCSS or CDCSS tone and the reception time of the DTMF are within 1 second, the power of the broadcasting amplifier is turned on. Turn on and start broadcasting, While the broadcast is in progress, acknowledging the reception of the signal for a predetermined time and confirming the input by the DTMF code, And if the broadcasting signal is not received for a predetermined time, or a predetermined DTMF signal is input, broadcasting a signal for notifying the end of the broadcasting and turning off the power of the amplifier. The method according to any one of claims 1 to 3, The security procedure Checking whether the carrier frequency transmitted from the radio is the same frequency as a predetermined frequency; Receiving three consecutive CTCSS or CDCSS signals together with the carrier frequency at one second intervals and confirming that the signals for each are identical to a predetermined signal; The amplifier controller checks the carrier frequency received from the receiver and the three different CTCSSs or CDCSSs, and if each equals to a predetermined signal, turns on the broadcasting amplifier and starts broadcasting. During a broadcast, when a broadcast signal is not received for a predetermined time of 5 seconds, or when a predetermined CTCSS or CDCSS signal is received for the end of a broadcast, broadcasting a signal for notifying the end of the broadcast and turning off the amplifier; Village amplifier system using a radio, characterized in that.