KR100636069B1 - A Method and Apparatus for FM broadcasting repeater using band division - Google Patents

Abstract

The present invention relates to a method and apparatus for re-broadcasting FM broadcasting using band division, which receives a broadcast signal from an external antenna and the external antenna, amplifies the signal into an appropriate size signal using a low noise amplifier, and then converts the signal to optical. FM LNA transmitting through the optical cable and the signal received from the optical cable through the optical cable by amplifying by dividing the band to have a different gain according to the band to have a uniform output and then sum it up. After the power amplification, the main repeater radiates through the leakage coaxial cable (RADIAX CABLE) and converts it to optical for transmitting to a higher output in a little further distance, and the output signal of the main repeater is transmitted through the optical cable to RF Sub-relay that is converted back to power amplification where needed and radiated through leaky coaxial cable The configuration is included, gives the relay an FM station so you can listen to FM radio stations on the underground environment, propagation does not have the effect of grounding by the ground, including underground tunnels and subways, or building.

Broadcast, Relay, Tunnel, Band Division, Optical

Description

Method and Apparatus for FM Broadcast Repeater using Band Division}

1 is a block diagram showing an overview of an FM broadcast retransmission apparatus using band division according to the present invention.

2 is a block diagram of an FM LNA according to the present invention.

3 is a block diagram of a main repeater according to the present invention.

4 is a block diagram of a band splitting circuit according to the present invention;

5 is a configuration diagram of a sub repeater according to the present invention.

6 is a flowchart illustrating an FM broadcast retransmission method using a band division scheme according to the present invention.

7 is a flowchart of a band division scheme according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: external antenna 20, 30, 30i: leakage coaxial cable

100: FM LNA 101, 201: optical cable

110: high voltage input capacitor 120: FM low pass filter (LPF)

130: low voltage amplifier (MMIC) 140: attenuator

150: optical transmitter 160: power supply

210: optical signal receiver 220: band division amplifier

230: broadcast signal output unit 240: optical transmitter

250: power supply 260: microcontroller

270: operation unit 280: latch

290: display unit 300, 300i: sub repeater

The present invention is a FM broadcast re-relaying method using a band-segmentation that relays the FM broadcast so that you can hear the FM radio broadcast in underground environments, such as tunnels, subways, or underground grounds of the building do not reach the radio wave And to an apparatus.

In general, the reception of radio broadcast signals is difficult due to radio wave shielding and interference phenomena in tunnels, underground shopping malls, underground facilities, and mountainous areas where radio wave interference is high. In order to improve such a problem, the broadcast signal is well received on the ground through the ground antenna, and the signal is amplified and radiated through the radiation antenna exposed from the inside of the tunnel or underground shopping mall.

Conventional FM radio repeaters include broadband, straight, and heterodyne methods. Among them, the broadband method is simple, inexpensive, and capable of relaying additional channels without additional equipment. There is a limit to the output. When a large signal and a small signal come in at the same time, only a large signal is relayed and a small signal may not be relayed well.

That is, it is greatly affected by the state of the input signal. In addition, the straight method and the heterodyne method select and relay channels that are radiated in the air. Since a separate sorting device must be provided to relay one channel, a sorting device corresponding to each channel is required to receive multiple channels. You must add as many channels as you want. As a result, the device is complex, expensive, and additional broadcasts cannot be relayed.

Therefore, additional costs are required to relay additional broadcasts. In addition, since several filters are used to screen one channel, maintenance of the filter is difficult due to aging.

The present invention can accommodate the advantages of the conventional broadband method and the advantages of the heterodyne method at the same time to configure the entire FM band (South Korea 20MHz band, 88MHz ~ 108MHz) by combining a certain band of amplification degree of each band By reducing the burden of the power amplifier by differently to equalize the input signal to provide a method and apparatus for the FM broadcast re-relay using a band division to relay all the channels to a high output.                         

The general broadcast signal prevents interference between adjacent channels by using guide channels, and also does not densely permit frequency intervals of broadcasts that are allowed for frequency reuse in each region.

By using this, the bands with weak signals among the incoming broadcasts are amplified with high gain, the bands with strong signals are amplified with low gain to equalize the size of the input signal, and the center frequency of each band can be arbitrarily changed to rebroadcast. Depending on the way the installer of the repeater is set up to configure the repeater for each environment by varying the combination of the various bands.

The band widths of the filters forming the band combination can be varied. (E.g. 8MHz, 5MHz, 2MHz bandwidth, etc.) If there is additional broadcasting, broadcasting can be done by user's device operation without adding additional device. You can also relay it.

In addition, relatively long distances, which are difficult to relay due to losses, can be relayed well by transmitting signals with light. In addition, the use of low-loss optical cables allows for scalability that can be easily extended to other systems in the future.

The FM broadcast retransmission method using band division for achieving the object of the present invention is a low noise amplification to amplify a broadcast signal received through an external antenna to an appropriate size through a low noise amplifier to the main signal of a remote place through an optical cable as an optical signal A transmission process for transmitting to the repeater; Receives the optical signal, restores the broadcast signal, and then amplifies it with different gains for each band by band-dividing, adds it, amplifies it, radiates it through a leaky coaxial cable, and converts the summed signal into an optical signal to a sub repeater A main broadcast relaying process for transmitting; And a sub broadcast relay process of restoring the broadcast signal received through the optical cable in the sub repeater and radiating it through the leakage coaxial cable after power amplification.

In addition, the FM broadcast re-broadcasting apparatus using band division for realizing the above method receives an external antenna and a broadcast signal from the external antenna, amplifies the signal into an appropriate size signal using a low noise amplifier, and then converts the signal into an optical signal. FM LNA which converts and transmits through the optical cable and the signal received through the optical cable from the FM ALN by amplifying by dividing the band to have a different gain according to the band to have a uniform output, and then add up, After the power amplification, it radiates through a leaky coaxial cable (RADIAX CABLE), and a main relay that converts and transmits light to radiate a higher output at a further distance, and the output signal of the main repeater is transmitted through an optical cable to receive an RF. Is converted back to power and amplified where it is needed and radiated through a leaky coaxial cable. It is characterized in configured to include the sub-relays.

The band-divided amplification is divided into at least one or more bands, and the band-specific amplification is performed by varying the combination of several bands according to a method set by the installer so that a plurality of bands can be combined for each environment. It is done.

The band division amplification is characterized in that a band with weak signals during broadcasting is amplified with a high gain and a band with strong signals is amplified with a low gain to amplify and sum the size of the input signal uniformly.

The first and second RF mixers are configured to allow the microcontroller to vary the center frequency of the first and second mixing stages by varying the frequency of the PLL to the center frequency set by the user.

The transmission to the sub repeater may include at least one or more optical transmitters and transmit the same to one or more sub repeaters.

The present invention can be used not only for FM radio broadcasting relay apparatus but also for unidirectional multichannel broadcasting relay apparatus, and can be applied to relay of digital broadcasting signal.

The characteristics of the present invention are characterized by amplifying different band divisions and amplification gains for each band so as to have an equal magnitude after amplification by the reception strength of signals for each band by band division. It is applicable to.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing an overview of an FM broadcast retransmission apparatus using band division according to the present invention.

As shown in this figure, the FM LNA 100, the main repeater (MAIN REPEATER) 200, and at least one sub repeater (SUB REPEATER) 300, 300i, and consists of the number of tunnels or broadcasts The sub repeater 300i may be expanded according to the expansion of the region.

The FM LNA 100 receives a broadcast signal through an external FM antenna 10 and transmits the broadcast signal to the main repeater 200 through the optical cable 101, and the plurality of subs in the main repeater 200. Broadcast signals are transmitted to the repeaters 300 and 300i through the optical cable 201, and the broadcast signals are transmitted through the leaky coaxial cables 20 and 30 and 30i in the main repeater 200 and the sub repeaters 300 and 300i, respectively. It is configured to rerun.

According to the present invention having such a configuration, as shown in FIG. 6, a low noise amplification of a broadcast signal received through an external antenna is transmitted to a main broadcast repeater 200 at a remote location through an optical cable as an optical signal (S100). After receiving the optical signal, the broadcast signal is restored and then amplified with different gains for each band by band dividing, and then amplified and then amplified and radiated through a leaky coaxial cable. The main broadcast relay process (S200) for transmitting to the repeater 300, and the sub-broadcast relay process (S300) for restoring the broadcast signal received through the optical cable in the sub repeater 300 and radiating through the leakage coaxial cable after power amplification (S300) Will be performed.

First, in the FM LNA 100, it receives an external FM signal, amplifies it into a signal having a proper size with a low noise amplifier, converts it into light, and transmits it to the main repeater 200. Because it transmits by light, it is not restricted by the distance and is easy to construct.

The signal coming into the main repeater 200 has different gains according to the band, and thus has a substantially uniform output, which is amplified by power and radiated through the leaky coaxial cable 20. In addition, the signal is converted to light and sent to the sub repeaters 300 and 300i in order to emit the signal at a higher distance.

The signal sent to the sub repeaters 300 and 300i is converted back to RF and amplified where necessary. In addition, such a sub repeater (300, 300i) can be expanded according to the number of places required.

A low noise amplification of the broadcast signal received through the external antenna to transmit the optical signal to the main broadcast repeater 200 in the remote place through the optical cable (S100) is performed by the FM LNA (100), which is shown in FIG. It is configured as shown.

2 is a block diagram of an FM LNA according to the present invention. As shown therein, the high voltage capacitor 110 prevents a high voltage DC power from entering the input circuit, an FM low pass filter (LPF) 120 which prevents an input signal other than an FM signal from being input, and A low noise amplifier 130 for amplifying a signal input through the low pass filter 120, a 2dB attenuator 140 for impedance matching of the output of the amplifier 130 and the next stage, and an attenuator 140 It comprises an optical transmitter 150 for transmitting the impedance matched signal through the optical cable 101 and a power supply 160 for supplying power to each part.

The FM LNA 100 configured as described above, the sudden surge or DC of the input signal is cut off by the high voltage input capacitor 110, the signal lower than the FM band of the input signal is not easily caught in the FM antenna and is higher than the FM band. The signal is removed from the FM low pass filter (LPF) 120. The FM signal thus input is amplified by a low noise amplifier (MMIC) 130 having a low noise figure and transmitted to the optical transmitter 150. At this time, the 2dB attenuator 140 was inserted between the optical transmitter 150 and the amplifier 130 in order to more surely match the impedance.

The signal transmitted from the FM LNA 100 via the optical cable 101 is received by the main repeater 200 to broadcast the broadcast, and the main repeater 200 receives the optical signal to restore the broadcast signal to the band division. By amplifying with different gains for each band by amplifying and then amplifying the power, radiating it through a leaky coaxial cable, and converting the summed signal into an optical signal and transmitting it to a sub repeater (S200).

The main broadcast relay process (S200), an optical signal receiving step (S210) for receiving the broadcast signal received through the optical cable to the optical receiver to convert the FM signal to remove the noise after amplification, a plurality of signals The band division amplification step (S220) of dividing the signal into bands and dividing them by bands and amplifying and re-adding the gains for each band, and after amplifying the bands, filters the summed signals and amplifies the power amplification again. And broadcast signal output step of emitting through the leak coaxial cable (S240) and; In step S250, the signal amplified after filtering in the broadcast signal distribution step is distributed through a splitter, converted to an optical signal through an optical transmitter, and transmitted to the sub-relay 300 through an optical cable 201. Will be done.

The main broadcast repeater for performing the main broadcast repeating process as described above is configured as shown in FIG. 3.

3 is a configuration diagram of a main repeater according to the present invention.

As shown in the drawing, the signal input from the optical cable 101 is received through the optical receiver 211 including the high-voltage capacitor through the band pass filter 212 and then processed by the AGC amplifier 213 in the next stage. The optical signal receiver 210 for amplifying to a suitable size below, and the signal of the optical signal receiver 210 is distributed through the input signal splitter 221 through a plurality of band division circuits 222 for each band. Band gain amplifier 220 for amplifying with a different gain and summing through the output signal adder 223 and outputting the band split amplifier 220 through a band pass filter 231 for gain amplification. A broadcast signal output unit 230 for radiating a broadcast signal through the power amplifier 234 and the power low pass filter 235 through the leakage coaxial cable 20 through the post distributor 233 through 232; In the splitter 233 of the broadcast signal output unit 230 At least one optical transmitter 240 and at least one optical transmitter 240 for converting the multiplied signal into an optical signal to transmit a broadcast signal to at least one sub-relay 300 through the optical cable 201, and each of the band split amplifier 220 A microcontroller 260 for adjusting the PLL center frequency band of the band division circuit, an operation unit 270 for setting the center frequency through the microcontroller 260, and a latch 280 for storing the set center frequency information. And a display unit 290 for displaying operation and operation states, and a power supply 250 for supplying power to the respective units.

The main repeater 200 configured as described above converts the signal transmitted from the FM LNA 100 to the optical signal through the optical receiver 211 and converts the signal into an FM signal again and converts other signals generated in the conversion process into a 20 MHz band pass filter (BPF). Removed at (212). The signal amplified to an appropriate size through the ACG amplifier 213 is input to each band division circuit 222 through the 9 divider 221. That is, the 20MHz band is divided into nine frequency bands and amplified with different gains. If there is no reason to divide into nine pieces, the band is divided into smaller numbers, and the remaining terminals of the divider 221 are dummy processed for impedance matching.

Here, the band division amplifier 220 performs a band division amplification step (S220) as shown in FIG. 7, which distributes the broadcast signal input from the distributor 221 through a mixer to the center frequency of the PLL. And a first mixing step of mixing with an intermediate frequency band, attenuating for amplifying and amplifying a predetermined size after converting the intermediate frequency band, and filtering the amplified signal through only a desired frequency bandwidth. The band filtering step and a second mixing step of mixing the signal of the desired frequency band with the center frequency of the PLL, converting the signal into the frequency of the original band, and filtering and outputting the same.

The band division amplification method as described above is performed in the band division circuit according to the present invention shown in FIG. As shown in FIG. 4, a low pass filter 401 for noise removing filtering of a signal input from the band divider 221 and a first RF for converting an output signal of the low pass filter 401 into an intermediate frequency band. A mixer 402, a variable attenuator 403 for attenuating the intermediate frequency signal of the first RF mixer 402 for impedance matching with the next stage, and amplifying an output signal of the variable attenuator 403 to a predetermined size SAW bandpass filter 405 for dividing the band by passing only the predetermined band through the amplifier 404, the output signal of the amplifier 404, and only the predetermined band through the bandpass filter 405. A second RF mixer 406 for mixing to have a passed frequency band, a low pass filter 407 for filtering and outputting a signal of the second RF mixer 406, and a frequency varying function for the first and second filters; Including a PLL 408 for adjusting the center frequency band of the RF mixer 406 It is sex.

In the band dividing circuit 222 configured as described above, when the signals of the entire 20 MHz band are input to the band dividing circuit 222, the band dividing circuit 222 is converted into the intermediate frequency band through the first RF mixer 402 after passing through the low pass filter 401. After adjusting to an appropriate size through the variable attenuator 403 and the amplifier 404, only the desired frequency band is filtered through the SAW filter 405. When this is converted back to the original band through the second RF mixer 406, it has a frequency band corresponding to the band of the SAW filter, and the center frequency of the frequency band is changed according to the frequency of the PLL 408. Can be. That is, the width of the band is determined according to the bandwidth of the SAW filter 405 and the center frequency is changed according to the frequency of the PLL 408. Here, the band of the SAW filter 405 is taken as an example of 0.5 ~ 10MHz band.

In addition, the PLL 408 measures the broadcast reception sensitivity of the field in advance and allocates the band to the band according to the reception intensity, and sets the center frequency for each band to be pre-divided in the microcontroller 260 so as to be divided into each band. In addition, the microcontroller 260 may change the center frequency of the first and second RF mixers 402 and 406 by varying the frequency of the PLL 408 according to the set center frequency of each band.

That is, the center frequency of the PLL is set by controlling the center frequency by the microcontroller 260, which is stored in the latch 280 when the user manipulates the control unit 270 by using the set value and the microcontroller 260. Will be controlled. Here, the operation unit 270 may be a separate PLC operation unit, but may be any means capable of controlling the setting to the microcontroller 260 by connecting a PLC or a notebook computer. In this case, the display unit 290 may include only the LED for operating state display.

Here, the amplification unit 404, the installer in advance by measuring the reception sensitivity of the field by the experiment in advance, the microcontroller 260 to amplify the band with the weak signals in the high gain, the band with the strong signals in the low gain during the broadcast. ), And the microcontroller 260 controls the amplification gain of the amplifying unit to amplify the input signal so that the magnitude of the input signal is substantially uniform for each band. Of course, in the method of dividing the band, the microcontroller is controlled by setting the center frequency of the PLL so that it can be divided into bands which have been previously beaten by reception sensitivity.

Here, the variable resistor is installed in each of the amplifiers 404 without using the microcontroller 260, so that the installer may manually configure the amplification gain for each band when the repeater is installed, which uses a microcontroller. It is to configure the device in a simple structure.

Through the band split circuit 222, a 20 MHz band is formed by a combination of predetermined bands, and the amplitude of each band is adjusted differently so that the size of the input signal is substantially uniform for each band. In this case, the uniformity does not mean that the signal of each band is the same, but the signal intensity of each band after amplification satisfies all within a predetermined range. To make it possible.

 Therefore, through the band dividing circuit 222, the bands with weak signals during broadcasting are amplified with high gain and the bands with strong signals with low gain to make the size of the input signal uniform, and center of each band. The frequency can also be arbitrarily changed so that the combination of various bands can be configured according to the method set by the installer of the rebroadcast repeater to configure a repeater suitable for each environment.

The signals from the multiple band split circuits 222 are combined through a 9-way summer 223 to form a 20 MHz band, and then the PLL frequency (local frequency) is removed through the low pass filter 231. Only the FM signal is left, and is amplified to a predetermined size through the gain amplifier 232.

The adjusted signals divider 233 allows the SUB repeaters 300 and 300i to go to each other, and one of the divided signals is connected to the power amplifier 234 inside the main repeater MAIN REPEATER. After being amplified, the spurious is removed through the power low pass filter (LPF) 235 and radiated to the underground environment through the leaky coaxial cable 20. In addition, the remaining signals are transmitted to the respective sub repeaters SUB REPEATER through the optical cable 201 converted into light through the optical transmitter 240.

5 is a configuration diagram of a sub repeater according to the present invention.

As shown in the figure, an optical receiver 310 receiving a signal transmitted from the main repeater 200 through the optical cable 201, and a band pass filter for passing only a predetermined band in the signal of the optical receiver 310 ( 320, a drive amplifier 330 for amplifying the signal filtered to a predetermined frequency band, and a power amplifier 340 for amplifying the power of the amplified signal, and removing noise of the power amplified signal. FM low pass filter 350 that radiates through the leakage coaxial cable 30, and a power supply 360 for supplying power to each part.

In the sub repeater 300 configured as described above, the input optical signals are converted into RF signals through the optical receiver 310 and other signals generated during the conversion are removed while passing through the band pass filter (BPF) 320. This signal is amplified by a suitable signal in the drive amplifier 330, amplified in the HPA (power amplifier) 340 and spurious is removed through the LPF 350 is radiated to the leaky coaxial cable 30.

In the present invention, almost all the circuits in the repeater can be automatically adjusted, but the center frequency of the band-slicing circuit should be changed according to the user's setting, which is digitally controlled using the microcontroller 260 and the latch 280. To control. That is, the user sets the relay frequency while looking at the display unit 290 through the operation unit 270, and the microcontroller 260 provides the latch 280 with information for controlling the frequency of the PLLs of the PLLs of the respective band split circuits 222. If the local frequency of the PLL is changed based on the information, the center frequency of the band dividing circuit is changed so that only the PLL frequency setting is controlled.

As described in detail above, according to the present invention, bands with weak signals during broadcasting for each band are amplified with high gain, and bands with strong signals are amplified with low gain, so that the size of the input signal is uniform. In addition, the center frequency of each band can be arbitrarily changed, so that the combination of the various bands can be varied according to the method set by the installer of the rebroadcast repeater to configure a repeater suitable for each environment.

In addition, the present invention can be broadcast by the operation of the user's device without the addition of a separate device, and because it is not a method of selecting one channel, there is an effect that can be relayed even if there is FM broadcast.

In addition, the present invention has the effect that it can be relayed well by transmitting signals even in a relatively long-distance area that is difficult to relay due to the existing loss, and easy to use other systems in the future by using a low-loss optical cable This has the effect of having extensibility to scale.

Claims (16)

A transmitting step of amplifying a broadcast signal received through an external antenna to an appropriate size through a low noise amplifier and transmitting it to a main broadcast repeater at a remote location; An optical signal receiving step of receiving the received broadcast signal with an optical receiver, removing noise, and amplifying the received broadcast signal; A band division amplifying step of dividing the received optical signal into a plurality of signal stages and dividing the band into bands and amplifying the gains for each band differently and then summing them again; Amplifying the band after the band division, filtering the summed signal, amplifying again, and then amplifying the power to radiate through the leaky coaxial cable; And transmitting the signal amplified after filtering in the broadcasting signal radiating step through a splitter, converting the amplified signal into an optical signal through an optical transmitter, and transmitting the optical signal to a sub repeater. Way. delete delete The method of claim 1, The band division amplification step, By splitting at least one or more bands into a plurality of bands, band banding is characterized in that amplification is performed for each band by combining a plurality of bands according to a method set by an installer so that a plurality of bands can be combined for each environment. FM broadcast re-transmission method. The method of claim 1, The band division amplification step, The FM broadcast retransmission method using band division, characterized in that the band with the weak signals during the broadcast is a high gain, the band with a strong signal is amplified with a low gain to amplify and sum the size of the input signal uniformly. The method of claim 1, The band division amplification step, A first mixing step of converting the broadcast signal distributed by the distributor and input into the intermediate frequency band by mixing with the center frequency of the PLL through a mixer; An amplifying step of converting to the intermediate frequency band and amplifying the attenuation and a predetermined size for impedance matching; A band filtering step of filtering the amplified signal by passing only a desired frequency bandwidth; And performing a second mixing step of mixing the signal of the desired frequency band with the center frequency of the PLL, converting the signal into the frequency of the original band, and then filtering and outputting the signal. The method of claim 6, The first and second mixing step, And a microcontroller may vary the frequency of the PLL to a center frequency set by a user so as to vary the center frequency of the first and second dimming steps. The method of claim 1, The step of transmitting to the sub repeater, And at least one or more optical transmitters and transmitting them to one or more sub-relays. In the broadcast re-relay device for relaying the broadcast signal so that the broadcast can be heard in an environment that does not reach the radio wave, An external antenna for receiving an over-the-air broadcast signal; FM LNA (LNA) that receives the broadcast signal from the external antenna and amplifies the signal of a suitable size with a low noise amplifier, and then converts it to optical transmission; The signal received from FM FM is divided by amplifying the band to have a different gain according to the band to have a uniform output, then summed up, and then amplified and radiated through a leaky coaxial cable. In addition, the main repeater that converts and transmits the light in order to emit at a higher distance to a higher output, Receiving the output signal of the main repeater is converted back to the RF signal, the power amplification in the necessary place, and the FM broadcast re-relay apparatus using a band split, characterized in that it comprises a sub-relay radiating it through a leaky coaxial cable. delete The method of claim 9, The main repeater, Optical signal receiving unit for receiving the input signal through the optical receiver 211 including a high-voltage capacitor through the band pass filter 212 and then amplified to a size suitable for processing in the next stage through the AGC amplifier 213 ( 210), The signals of the optical signal receiver 210 are distributed through the input signal divider 221, amplified by different gains through the plurality of band division circuits 222 for each band, and summed through the output signal adder 223. Band splitting amplifier 220 for outputting the; The band split amplifier 220 outputs the bandpass filter 231 through the gain amplifier 232 and then through the divider 233 through the power amplifier 234 and the power low pass filter 235. And a broadcast signal output unit 230 for emitting a broadcast signal through the leaky coaxial cable 20, At least one light is provided to convert the signal distributed by the splitter 233 of the broadcast signal output unit 230 to an optical signal to transmit the broadcast signal to at least one or more sub-relay 300 through the optical cable 201 Transmitter 240, A microcontroller 260 for adjusting the PLL center frequency band of each band division circuit of the band division amplifier 220; An operation unit 270 for setting a center frequency through the microcontroller 260, A latch 280 for storing set center frequency information; A display unit 290 for displaying an operation and an operation state; And a power supply unit (250) for supplying power to the respective units. The method of claim 11, The band division circuit, A low pass filter 401 for noise removing filtering of a signal input from the band divider 221, A first RF mixer 402 for converting the output signal of the low pass filter 401 into an intermediate frequency band, A variable attenuator 403 for attenuating the intermediate frequency signal of the first RF mixer 402 for impedance matching with the next stage; An amplifier 404 for amplifying the output signal of the variable attenuator 403 to a predetermined size; A SAW bandpass filter 405 for band-dividing the output signal of the amplifier 404 by passing only a predetermined band; A second RF mixer 406 mixing the band pass filter 405 to have a frequency band passed through only a predetermined band, A low pass filter 407 for filtering and outputting the signal of the second RF mixer 406, And a PLL (408) for adjusting a center frequency band of the first and second RF mixers (402, 406) with a frequency varying function. The method of claim 12, The amplification unit, The installer preliminarily measures the reception sensitivity in the field and sets the amplification gain in the microcontroller so that the band with weak signals during the broadcast is amplified with a high gain and the band with strong signals is amplified with a low gain. And amplifying the gain of each band to control the amplification of the input signal so that the amplitude is uniform for each band. The method of claim 12, The amplification unit, The installer can measure the reception sensitivity of the site by experiment in advance so that the amplification gain of each amplification unit can be manually set through the variable resistor to amplify the band with the weak signals with high gain and the band with the strong signals with low gain during broadcasting. FM broadcast retransmission apparatus using a band split, characterized in that configured to. The method of claim 12, The PLL is, The installer measures the broadcast reception sensitivity in the field in advance and allocates it to the band by reception sensitivity, sets the center frequency for each band to be pre-divided into the microcontroller so that it can be divided into each band, and sets the center frequency for each band where the microcontroller is set. And the frequency of the PLL to vary the center frequency of the first and second RF mixers. delete

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