KR102146190B1 - Voice data recoding system based on dual band frequency - Google Patents

Abstract

The present invention relates to a voice data recording system based on a dual-band frequency, which comprises: a transmission unit for receiving an external voice signal and transmitting the signal through an ISM band radio frequency channel; and a reception unit receiving, storing, and playing the voice signal transmitted from the transmission unit and installed in the vehicle. The reception unit operates at an ISM band radio frequency of a dual channel. The voice data recording system based on a dual-band frequency operates a first channel of a high frequency band with excellent sound quality when a distance between a wireless microphone and the reception unit is close and additionally operates a second channel capable of long-distance transmission when the distance between the wireless microphone and the reception unit increases so that high-quality voice signals can be recorded and played regardless of the distance between the wireless microphone and a reception antenna.

Description

Voice data recording system based on dual band frequency {VOICE DATA RECODING SYSTEM BASED ON DUAL BAND FREQUENCY}

The present invention is capable of continuously recording and reproducing high-quality voice signals by selecting a communication frequency band according to the distance and obstacle environment between the voice signal transmitter (wireless microphone) and the receiving antenna by operating the frequency bands of two channels. It relates to a dual-band frequency-based voice data recording system.

Recently, disputes over illegality or compliance of case handlers in the process of handling cases at crime scenes are increasing, and disputes over the presence or absence of illegal acts such as assault against the handlers (emergency personnel) are increasing in the process of handling accidents. In various accidents and crime scenes, the importance of recording data on the process as well as handling the situation is emerging.

Such various types of data may include, for example, video recording data of accidents and crime scenes, audio recording data such as voice and sound, etc. The recording, reproduction, and management of such video and audio data can be performed in the process of various accidents and incidents. It is very important in terms of securing legal evidence for Korea. In particular, it is an essential element in vehicles such as police security patrol cars, and it is becoming an essential equipment for public affairs workers such as emergency rescue personnel and firefighters.

On the other hand, with regard to recording and reproducing audio data, the modulated voice signal transmitted from the transmission antenna of the wireless microphone using a specific modulation and demodulation method is received by the reception antenna of the base receiver through the ISM (Industrial, Scientific and Medical) frequency band. Is stored and played back. The ISM frequency band is a frequency band that can be used without a license for industrial, scientific, medical, home, and other similar purposes other than telecommunications, and the 2.4GHz frequency band and 900MHz frequency band are mainly used.

However, in the case of the 2.4GHz frequency band, high-quality transmission is possible, but there is a problem that the transmission distance is short, about 100 meters, and in the case of the 900MHz frequency band, the transmission distance is possible up to several kilometers, but there is a problem that the quality of sound is deteriorated.

1. Korean Patent Registration No. 10-1050897 (Wireless microphone unit for vehicle data recording system) 2. Republic of Korea Patent Publication No. 20-2015-0004538 (portable video and audio recording device)

The present invention is to solve the problems of the prior art as described above, and an object of the present invention is to select an optimal communication frequency band according to a distance between a wireless microphone and a receiving antenna and an obstacle environment to continuously and continuously transmit high-quality voice data. It is to provide a dual-band frequency-based voice data recording system that can record and play.

One aspect of the present invention for achieving the above object is a transmission unit for receiving an external voice signal and transmitting it through an ISM band radio frequency channel; And a receiving unit that receives, stores and reproduces the voice signal transmitted from the transmitting unit, and is installed at a moving base.

The receiving unit is operated with a dual channel ISM band radio frequency, wherein the dual channel is a high frequency band channel of a 2.4 GHz band or 5.0 GHz band and a low frequency band channel of a 400 MHz band or 900 MHz band,

The transmitting unit and the receiving unit relate to a dual-band frequency-based voice data recording system, characterized in that the high-frequency band channel or the low-frequency band channel is selected and set according to the signal strength of a received voice signal to transmit and receive voice data. .

In the voice data recording system based on a dual band frequency according to an embodiment of the present invention, the transmission unit comprises: a microphone receiving an analog voice signal; An amplifier for amplifying the analog voice signal to a preset size; An A/D converter for converting the audio signal to analog/digital; A speech encoder for compressing a speech signal; An RF transmitter for transmitting a voice signal through the dual channel; And a controller that controls each operation of the transmission unit. It may be configured to include.

In addition, the transmission unit may be made of a wireless microphone.

In addition, the wireless microphone may be detachable from the user's clothing or helmet.

Further, the wireless microphone may include a self-memory function for temporarily storing a compressed voice signal.

And, the receiving unit, the receiving unit for receiving a voice signal through the dual channel; A control unit controlling setting and releasing of the dual channel; A speech decoder for decoding a speech signal: a D/A converter for digital/analog conversion of a speech signal; An amplifier that amplifies the analog audio signal to a preset size; And an output unit for outputting an audio signal.

In addition, the receiving unit may further include a light emitting element that displays an operating state of the receiving unit.

In addition, the reception unit may be configured to set a voice signal reception channel through a high frequency band channel of a 2.4 GHz band or 5.0 GHz band when a communication channel setting request is requested.

In addition, the reception unit may be configured to set a voice signal reception channel through a low frequency band channel of a 400 MHz band or a 900 MHz band when a response signal is not received in response to a request for establishing a communication channel through the high frequency band channel.

Further, the receiving unit may be configured to additionally set the low frequency band channel when the voice signal strength of the high frequency band channel is less than or equal to a preset first set value.

In addition, the receiving unit may be configured to stop the operation of the high frequency band channel and receive the voice signal through only the low frequency band channel when the sound signal strength of the high frequency band channel is less than or equal to a preset first limit value.

Further, the receiving unit may be configured to additionally set the high frequency band channel when the voice signal strength of the low frequency band channel is equal to or greater than a preset second limit value.

Further, the receiving unit may be configured to stop the operation of the low frequency band channel and receive the voice signal through only the high frequency band channel when the voice signal strength of the low frequency band channel is greater than or equal to a preset second set value.

In addition, when the remaining battery capacity of the transmitting unit is less than or equal to a preset capacity, the receiving unit may stop the dual channel operation and switch to a single operation mode of a high frequency band channel or a low frequency band channel.

In addition, the receiving unit may change the first set value and the first limit value so as to reduce the range from the first set value to the first limit value when the remaining battery capacity of the transmitting unit is less than or equal to a preset capacity. have.

In addition, the reduction amount of the range between the first set value and the first limit value may be set in proportion to the remaining amount of the battery.

In addition, when the remaining battery capacity of the transmitting unit is less than or equal to a preset capacity, the receiving unit may change the second set value and the second limit value to reduce a range from the second set value to the second limit value. have.

In addition, the reduction amount of the range between the second set value and the second limit value may be set in proportion to the remaining amount of the battery.

In addition, when the dual channel operation time continues for a preset time or longer, the receiving unit may stop the dual channel operation and switch to a single operation mode of a high frequency band channel or a low frequency band channel.

In addition, the receiving unit may further include a recorder including a player including an A/V codec for reproducing the stored audio signal.

In addition, the recorder may selectively store a voice signal according to an instruction transmitted from the control unit.

In the dual-band frequency-based voice data recording system according to the present invention having the above configuration, a wireless microphone and a receiving antenna are operated by simultaneously or respectively operating dual frequency bands of a high frequency band channel or a low frequency band channel according to the strength of a received voice signal. It has the effect of continuously recording and reproducing high-quality voice signals regardless of the distance between them and the environment of obstacles.

In addition, the dual-band frequency-based voice data recording system according to the present invention has a problem in that the battery of the wireless microphone away from the vehicle is discharged by adjusting the number of channels operated according to the remaining capacity of the wireless microphone battery, so that recording at an important moment cannot be performed. There is an effect that can be solved.

1 is a schematic perspective view of a vehicle voice recording apparatus according to an embodiment of the present invention.
2 is a block diagram of a transmission unit in a vehicle voice recording apparatus according to an embodiment of the present invention.
3 is a block diagram of a receiving unit in a vehicle voice recording apparatus according to an embodiment of the present invention.
4 is a detailed block diagram of the receiving unit.
5 is a perspective view of a transmitting unit (wireless microphone) used in the vehicle voice recording apparatus of the present invention.
6 is a block diagram for explaining the operation of the vehicle voice recording apparatus according to an embodiment of the present invention.

In the present invention, since various transformations can be applied and various implementations can be provided, specific implementations will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, when it is determined that a detailed description of a related known technology may obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance. In addition, in the present application, the term "voice signal" should be followed by referring to all audio signals, not just human voices.

Hereinafter, a dual-band frequency-based voice data recording system of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a schematic perspective view of a dual-band frequency-based voice data recording system according to an embodiment of the present invention, and FIG. 2 is a block diagram of a transmission unit, which is a component of a dual-band frequency-based voice data recording system according to the present invention. Fig. 3 is a block diagram of a receiving unit, and Fig. 4 is a detailed block diagram of the receiving unit.

1 to 4, the dual-band frequency-based voice data recording system according to the present invention largely includes a transmitting unit 100 and a receiving unit 200.

In the present invention, the transmission unit 100 includes a controller 120, buttons and LEDs 102 to 107, a microphone 108, an amplifier 150, an A/D converter 140, a voice encoder 130, A memory 190, a power supply 180, and an RF transceiver 110 may be included.

In addition, the receiving unit includes an RF transceiver 210, a control unit 220, a voice decoder 230, a D/A converter 231, an amplifier 232, a speaker 233, a power supply unit 270, and a recorder. Can include.

In the present invention, the transmission unit 100 may be formed of a wireless microphone. In this case, the wireless microphone 100 may be of a type detachable from the user's clothing or helmet. Accordingly, when a police officer or the like is urgently pursuing a criminal, there is no need to separately carry the wireless microphone 100 when tracking the criminal, and there is no need to hold the wireless microphone 100 by hand, so both hands can be used freely. .

5 is a perspective view of the wireless microphone 100 according to the present invention. Hereinafter, the configuration of the transmission unit 100 will be described in more detail with reference to FIGS. 5 and 2.

According to the present invention, the transmitting unit 100 includes a wireless microphone main body case 101 and a record button 103 to 105 exposed to the outside of the main body case 101, a channel use display LED 102, and a battery status display. It may include an LED 106 and an emergency button 107 to be pressed in an emergency state. The channel usage indicator LED 102 is green when transmitting a high-frequency band channel in the 2.4 GHz band or 5.0 GHz band, and blue when using a dual channel of a high-frequency band channel and a low-frequency band channel, or a 400 MHz band or 900. In the case of using a low frequency band channel of the MHz band, it may be displayed as red. Hereinafter, the high frequency band channel refers to a channel in the 2.4 GHz band or 5.0 GHz band of the ISM frequency band, and the low frequency band refers to a channel in the 400 MHz band or 900 MHz band band.

At this time, the interior of the main body case 101, a microphone 108 for receiving an analog voice signal; An amplifier 150 for amplifying the electrical analog voice signal received from the microphone 108 to a predetermined level after band pass filtering (BPF) into a voice band; An A/D converter 140 converting the analog audio signal amplified from the amplifier 150 into digital audio data; And a voice encoder 130 that compresses digital voice data received from the A/D converter 140 by an audio codec (such as an MP3 codec).

In addition, the wireless microphone 100 may include a memory 190 temporarily storing compressed voice data; A power supply unit 180 for supplying power from a DC 5V battery; And transmitting a voice signal modulated by any one of amplitude modulation (AM: Amplitude Modulation), frequency modulation (FM: Frequency Modulation), or pulse code modulation (PCM: Pulse Code Modulation) modulation of the compressed voice data in real time. It may include an RF transmitter 110 for transmitting to the ISM band radio frequency channel of the antenna and a controller 120 for controlling each operation of the wireless microphone 100. The RF transmitter 110 includes a first transmission module 111 for transmitting using a high frequency band of 2.4 GHz band or 5.0 GHz band, and a second transmission module 112 for transmitting in a low frequency band of 400 MHz band or 900 MHz band. ) Can be included. In this case, a vibration sensor 150 for sensing vibration of the wireless microphone 100 and an A/D converter for A/D conversion of the vibration signal sensed from the vibration sensor 150 may be additionally included (not shown).

In the present invention, the transmission antenna
It can be composed of ANT 1 transmitting through a high frequency band channel of the 2.4 GHz band or 5.0 GHz band and ANT 2 transmitting through a low frequency band channel of the 400 MHz band or 900 MHz band.

In the present invention, the reception unit 200 receives the voice signal modulated by the ISM band radio frequency channel from the transmission unit 100, filters noise, and demodulates it in a corresponding demodulation (AM, FM, PCM, etc.) method. , An RF receiver 210 for detecting voice; A control unit 220 for controlling synchronization, demodulation, and voice storage and output functions of each block; A voice decoder 230 for decoding and restoring compressed voice data: a D/A converter 240 for converting digital voice data provided from the voice decoder 230 into an analog voice signal; An amplifier 250 amplifying an analog audio signal from the D/A converter 240 to a predetermined level; A speaker 260 outputting an amplified analog audio signal from the amplifier 250; A power supply unit 280 for supplying power to a battery or an AC voltage through an adapter; And a recorder 290 for storing the control program and voice data. And it may be configured to include an LED 270 for displaying the voice recording state and the use or not, and the charging state.

In the present invention, the RF receiver 210 may include an ANT 1 for receiving a high frequency band of a 2.4 GHz band or a 5.0 GHz band and an ANT 2 for receiving a low frequency band of a 400 MHz band or 900 MHz band. In addition, a first receiving module 211 that receives a voice signal from ANT 1 to filter, demodulates and detects noise, and a second receiving module 212 that receives a voice signal from ANT 2 to filter, demodulate and detect noise. It may include.

In the present invention, the receiving unit 200 may be installed inside a vehicle.

Hereinafter, the operation of the dual-band frequency-based voice data recording system according to the present invention will be described.

The dual-band frequency-based voice data recording system according to the present invention starts voice data transmission through channel setting in two types. The first is an embodiment in which a channel is set by the receiving unit 200. When the receiving unit 200 detects the departure of the transmitting unit 100, the receiving unit 200 sends a high-frequency band channel setting request signal. When transmitting to the transmitting unit 100, the transmitting unit 100 sets a high-frequency band channel and transmits the sound signal modulated in real time to the receiving unit 200 through a high-frequency band channel of the 2.4 GHz band or 5.0 GHz band. .

Meanwhile, the second embodiment is an embodiment in which a channel is set by the transmission unit 100, and the transmission unit 100 provided by the user transmits a channel setting request to the reception unit 200 to set a transmission/reception channel. At this time, the transmission unit 100 initially transmits a channel setting request signal through a high-frequency band channel of the 2.4 GHz band or 5.0 GHz band. In this case, when the transmission unit 100 cannot receive the response signal from the reception unit 200, the transmission unit 100 is in a state that the distance between the transmission unit 100 and the reception unit 200 deviates from the high-frequency band channel transmission distance. ) Again transmits a channel setting request signal through the low frequency band channel.

In the following description of the case of the first embodiment, in a state in which a high frequency band channel is set between the transmission unit 100 and the reception unit 200, the transmission unit 100 deviates from the reception unit 200 by a predetermined distance or more, When the voice signal strength of the channel is received below a preset first set value, the control unit 220 of the reception unit 200 requests the transmission unit 100 to set a low frequency band channel. In this case, the first preset value may be, for example, a moment when the voice signal strength of the high-frequency band channel reaches 80% of the maximum signal strength. Accordingly, according to the present invention, the transmission unit 100 operates ANT 1 and ANT 2 to simultaneously transmit a voice signal to a high frequency band channel of a 2.4 GHz band or 5.0 GHz band and a low frequency band channel of a 400 MHz band or 900 MHz band. Is done.

Meanwhile, when the transmission unit 100 deviates further from the reception unit 200 during the dual channel operation as described above and the voice signal strength of the high frequency band channel is received below a preset first limit value, the control unit of the reception unit 200 The 220 requests the transmission unit 100 to stop a high frequency band channel. At this time, the preset first limit value may be, for example, a moment when the voice signal strength of the high-frequency band channel reaches 40% of the maximum signal strength. Accordingly, according to the present invention, the transmission unit 100 operates only ANT 2 to transmit a voice signal through a low frequency band channel of 400 MHz band or 900 MHz band band.

At this time, as described above, when the transmission unit 100 returns to the reception unit 200 for a certain distance during operation of the low frequency band channel and the voice signal strength of the low frequency band channel is received above a preset second limit value, the reception unit 200 The control unit 220 requests the transmission unit 100 to set a high frequency band channel. In this case, the second limit value of the preset low frequency band channel may be, for example, a moment when the voice signal strength of the low frequency band channel reaches 40% or more of the maximum signal strength. Accordingly, according to the present invention, the transmission unit 100 operates ANT 1 and ANT 2 to simultaneously transmit a voice signal to a high frequency band channel of a 2.4 GHz band or 5.0 GHz band and a low frequency band channel of a 400 MHz band or 900 MHz band. Is done.

In addition, when the transmitting unit 100 approaches the receiving unit 200 closer to the receiving unit 200 and the audio signal strength of the low-frequency band channel is received above the second preset value, the receiving unit 200 The control unit 220 requests the transmission unit 100 to stop a low-frequency channel. At this time, the second preset value may be, for example, a moment when the voice signal strength of the low-frequency band channel reaches 80% of the maximum signal strength. Accordingly, according to the present invention, the transmission unit 100 operates only ANT 1 to transmit a voice signal through a high-frequency band channel of the 2.4 GHz band or 5.0 GHz band.

As described above, according to the present invention, according to the present invention, when the distance between the transmitting unit and the receiving unit is close, the high-frequency band channel with excellent sound quality is operated, and when the distance between the transmitting unit and the receiving unit is increased, a low-frequency transmission is possible. By additionally operating a band channel, it is possible to continuously record and reproduce a high-quality voice signal regardless of the distance between the transmitting unit and the receiving unit and an obstacle environment.

That is, if the user is gradually moving away from the receiving unit while holding the transmitting unit, transmission is performed through the high-frequency band channel with excellent sound quality up to the distance (location) where the channel strength of the high-frequency band is high, and the signal strength of the high-frequency band channel is lower In the domain, a high frequency band channel and a low frequency band channel are simultaneously operated to prevent interruption of transmission of a voice signal.

In this case, when the dual channel is operated, the battery usage of the transmitting unit increases, and thus the duration of the voice signal transmission may be shortened. Accordingly, according to the present invention, it is possible to operate the dual channel in various forms in consideration of power efficiency according to the remaining amount of the battery.

In the present invention, when the remaining battery capacity of the transmitting unit falls below a preset capacity, the receiving unit may be operated to stop dual channel operation and switch to a single operation mode of a high frequency band channel or a low frequency band channel. As a result, the battery use efficiency can be maintained to the maximum.

According to another embodiment, the receiving unit may stop the dual channel operation and switch to a single operation mode of a high frequency band channel or a low frequency band channel when the dual channel operation time lasts longer than a preset time. In this case, when the user is located for a long time in an intermediate region in which both the high frequency band channel and the low frequency band channel are set as dual channels, excessive battery waste can be prevented.

In addition, according to the present invention, the receiving unit further comprises a first set value and a first limit value so as to reduce the range from the first set value to the first limit value when the remaining battery capacity of the transmitting unit falls below a preset capacity. This is subject to change. In this case, the reduction amount of the range between the first set value and the first limit value may be set in proportion to the remaining amount of the battery.

In other words, if the remaining battery power remains above a certain amount, the range between the first set value and the first limit value is maintained to be large to ensure the quality and continuity of the voice recording stably. By minimizing the use of the battery by reducing the range, it is possible to prevent the battery of the wireless microphone from being completely discharged.

The operation mode as described above may be equally applied between the second set value and the second limit value.

Meanwhile, in the present invention, the audio signal received by the receiving unit is stored in a recorder of the receiving unit, and then, if necessary, the receiving unit reproduces the analog audio signal through its own speaker after audio decoding, D/A conversion, and amplification. At this time, the recorder may selectively record the voice recording according to the instruction of the control unit of the receiving unit. Accordingly, the receiving unit can suppress unnecessary power consumption and prevent an increase in the size of the memory.

Although the preferred embodiments of the present invention have been described above, those of ordinary skill in the relevant technical field can add, change, delete or add components within the scope not departing from the spirit of the present invention described in the claims. Various modifications and changes may be made to the present invention by addition or the like, and it will be said that this is also included within the scope of the present invention. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

The present invention relates to a dual-band frequency-based voice data recording system capable of recording and reproducing high-quality voice signals regardless of the distance between a wireless microphone and a receiving antenna by operating a two-channel frequency band. The band frequency-based voice data recording system operates a high-frequency band channel with excellent sound quality when the distance between the wireless microphone and the receiving unit is close, and a low-frequency band capable of long-distance transmission when the distance between the wireless microphone and the receiving unit increases. By operating additional channels, high-quality voice signals can be recorded and reproduced regardless of the distance between the wireless microphone and the receiving antenna.

100: transmitting unit 110: RF transmitting unit
120: controller 130: voice encoder
140: A/D converter 150: amplifier
180: power supply unit 190: memory
200: receiving unit 210: RF receiving unit
220: control unit 230: voice decoder
240: D/A converter 250: amplifier
260: speaker 270: LED
280: power supply 290: recorder

Claims (15)

A transmission unit for receiving an external voice signal and transmitting it through an ISM band radio frequency channel; And
Including; a receiving unit that receives, stores and reproduces the voice signal transmitted from the transmitting unit, and is installed at a moving base
The receiving unit is operated with a dual channel ISM band radio frequency, wherein the dual channel is a high frequency band channel of a 2.4 GHz band or 5.0 GHz band and a low frequency band channel of a 400 MHz band or 900 MHz band,
The transmitting unit and the receiving unit,
A voice data recording system based on a dual band frequency, characterized in that the high frequency band channel or the low frequency band channel is selected and set according to the signal strength of a received voice signal to transmit and receive voice data. The method of claim 1,
The transmission unit,
A microphone for receiving an analog voice signal;
An amplifier for amplifying the analog voice signal to a preset size;
An A/D converter for converting the audio signal to analog/digital;
A speech encoder for compressing a speech signal;
An RF transmitter for transmitting a voice signal through the dual channel; And
A controller that controls each operation of the transmission unit; To
A voice data recording system based on a dual-band frequency, comprising: The method of claim 2,
The transmission unit,
A voice data recording system based on a dual band frequency, characterized by consisting of a wireless microphone. The method of claim 3,
The wireless microphone,
A dual-band frequency-based voice data recording system, characterized in that it is detachable from the user's clothing or helmet. The method of claim 3,
The wireless microphone,
A dual-band frequency-based voice data recording system, comprising a self-memory function for temporarily storing a compressed voice signal. The method of claim 1,
The receiving unit,
A receiver for receiving a voice signal through the dual channel;
A control unit controlling setting and releasing of the dual channel;
Speech decoder to decode speech signals:
D/A converter for digital/analog conversion of audio signals;
An amplifier that amplifies the analog audio signal to a preset size; And
An output unit for outputting an audio signal; a dual-band frequency-based audio data recording system comprising: a. The method of claim 6,
The receiving unit,
A dual-band frequency-based voice data recording system, further comprising a light-emitting element for displaying an operating state of the receiving unit. The method of claim 6,
The receiving unit,
A voice data recording system based on a dual band frequency, characterized in that when a communication channel setting is requested, a voice signal reception channel is set through a high-frequency band channel of a 2.4 GHz band or 5.0 GHz band. The method of claim 8,
The receiving unit,
When a response signal is not received in response to a request for setting a communication channel through the high frequency band channel,
A voice data recording system based on a dual band frequency, characterized in that a voice signal reception channel is set through a low frequency band channel of 400 MHz band or 900 MHz band. The method of claim 8,
The receiving unit,
If the voice signal strength of the high frequency band channel is less than or equal to a preset first set value,
A voice data recording system based on a dual band frequency, characterized in that the low frequency band channel is additionally set. The method of claim 10,
The receiving unit,
If the voice signal strength of the high frequency band channel is less than or equal to a preset first limit value,
A voice data recording system based on a dual band frequency, characterized in that the operation of the high frequency band channel is stopped and a voice signal is received through only the low frequency band channel. The method of claim 11,
The receiving unit,
If the voice signal strength of the low-frequency band channel is more than a preset second limit value,
A voice data recording system based on a dual band frequency, characterized in that the high frequency band channel is additionally set. The method of claim 12,
The receiving unit,
If the voice signal strength of the low frequency band channel is more than a preset second set value,
A voice data recording system based on a dual band frequency, characterized in that the operation of the low frequency band channel is stopped and a voice signal is received through only the high frequency band channel. The method according to any one of claims 10 to 13,
The receiving unit,
If the operating time of the dual channel lasts longer than a preset time,
A dual-band frequency-based voice data recording system, characterized in that the dual-channel operation is stopped and the high-frequency channel or the low-frequency channel is switched to an independent operation mode. The method of claim 7,
The receiving unit,
A dual-band frequency-based voice data recording system, further comprising a recorder including a player including an A/V codec for reproducing the stored voice signal.

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