KR100244890B1 - Broadband amplification circuit - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wideband amplification circuit of a time division modulation method for amplifying the airwave broadcast signals of all channels to be uniform, and comprising: a broadcast signal input unit, a control unit, a broadcast signal amplifier unit, a level detection unit, and a broadcast signal output unit. It is configured to control the tuning frequency in sequence, and to reduce the gain of the signal with the large broadcast signal level and to increase the gain of the signal with the small broadcast signal level to adjust the gain for each of the tuning frequencies so that the broadcast signal level of all the tuning frequencies can be uniformly sized. By adjusting and amplifying, there is an effect that the receiver can clearly see all the broadcasting signals.

Description

Time Division Modulation Broadband Amplifier

1 is a block diagram of an underground broadcasting repeater in which a wideband amplification circuit of a time division modulation method according to the present invention is used.

2 is a block diagram of a wideband amplification circuit of a time division modulation scheme according to the present invention.

* Explanation of symbols for main parts of the drawings

10: broadcast signal input unit 20: control unit

30: broadcast signal amplifier 40: level detector

50: broadcast signal output unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wideband amplification circuit of a time division modulation scheme, and more particularly, to a wideband amplification circuit of a time division modulation scheme of amplifying such that the size of the airwave broadcasting signals of all channels is uniform.

Generally, in tunnels, underground parking lots, underground malls, broadcast radio waves do not arrive due to the shielding effect caused by the grounding of the ground or building structures, or the signal is weak so that broadcast reception is impossible. The broadcast broadcast signal must be relayed so that a clean broadcast can be viewed.

In general, in the broadcast relay apparatus, as shown in FIG. 1, an air wave broadcast signal is amplified by the wideband preamplifier 100, and the AM broadcast signal passes through the AM broadcast band filter 101, and then the first wideband amplification circuit 102 is performed. Amplified by the first wideband amplification circuit 102, the first band pass filter 103, the first wideband power amplifier 104, the first divider 105, and the plurality of first broadcast signals. After passing through the matching device 106 and the like is output through the antenna.

Of course, the FM broadcast signal is amplified by the second wideband amplifier circuit 108 after passing through the FM broadcast band filter 107, and the FM broadcast signal amplified by the second wideband amplifier circuit 108 is a second band pass filter. 109, the second wideband amplifier 110, the second divider 111, and the plurality of second matching devices 112 pass through the antenna.

That is, the conventional first and second broadband amplifiers 102 and 108 amplify all AM broadcast signals and FM broadcast signals with uniform amplification, and the amplified AM broadcast signals and FM broadcast signals are output through an antenna. It has been intended to reach places where broadcast radio waves do not arrive.

However, since the conventional broadband amplification circuit amplifies all the AM broadcast signals and the FM broadcast signals with uniform amplification, even if amplified, the broadcast signals of the channels, which are much weaker, are still weak and cannot receive clean broadcasts at the destination. there was.

Accordingly, the present invention has been made to solve the above-described problems of the prior art, and a wideband amplification circuit of a time division modulation scheme in which the size of all the over-the-air broadcast signals output by uniformly amplifying each of the input over-the-air broadcast signals has a uniform amplification degree. The purpose is to provide.

According to an aspect of the present invention, there is provided a broadcast signal input unit to which an over-the-air broadcast signal is input, and a control unit for outputting a control voltage signal for controlling a frequency channel to the broadcast signal input unit so that broadcast signals of time-divided channels are input. And a broadcast signal amplifier for amplifying the broadcast signal input by the gain control signal output from the controller at different amplification levels, and detecting a level of the broadcast signal amplified by the broadcast signal amplifier. And a broadcast signal output unit for outputting a broadcast signal amplified by the broadcast signal amplifier.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 2, the wideband amplification circuit of the time division modulation method according to the present invention includes a broadcast signal input unit 10 to which an over-the-air broadcast signal is input, and a control signal for controlling a frequency channel to the broadcast signal input unit 10. A control unit 20 for outputting time-divided broadcast signals of multiple channels and a broadcast signal amplifying unit 30 for amplifying a broadcast signal input by a gain control signal output from the control unit 20 at different amplification levels. And a level detector 40 for detecting the level of the broadcast signal amplified by the broadcast signal amplifier 30 and outputting a level detection signal to the controller 20, and amplified by the broadcast signal amplifier 30. It consists of a broadcast signal output part 50 which outputs a broadcast signal.

The broadcast signal input unit 10 is a broadcast input through the first antenna 11 and the second antenna 12 and the first antenna 11 and the second antenna 12 to which the same over-the-air broadcast signal is input. The combiner 13 which combines the signals and the voltage control tuning circuit 14 which selects the channel input by the control voltage output from the said control part 20 are comprised.

The control unit 20 also controls the central processing unit 21 and the tuning circuit 14 of the broadcast signal input unit 10 according to the information stored in the ROM 22 under the control of the central processing unit 21. The first latch unit 24 'and the 1DAC 24 outputting a voltage control signal to the control unit and the level detection signal output from the level detector 40 are controlled by the central processing unit 21. A second latch unit 25 'and an ADC 25 stored in the unit 23; and a third latch unit outputting a gain control signal to the broadcast signal amplifier unit 30 under the control of the central processing unit 21; The clock signal is output to the first, second, and third latch units 24 ', 25', and 26 'under the control of the unit 26' and the second DAC 26 and the central processing unit 21. The decoder 27 is comprised.

The broadcast signal amplifying unit 30 attenuators 31, preamplifiers 32, and dividers which attenuate the broadcast signal output from the voltage control tuning circuit 14 by the gain control signal output from the second DAC 26. 33) and a wideband power amplifier 34 or the like.

The broadcast signal output unit 50 includes a directional coupler 51, a leakage coaxial cable 52, and a dummy load that receive the output signal of the broadband power amplifier 34.

In this example, the gain control signal output from the second DAC 26 is input to the attenuator 31. This may be input to the ALC terminal of the broadband power amplifier 34 or the voltage control signal of the preamplifier 32. The level detector 40 detects the level of the broadcast signal in the distributor 33, but may detect the broadcast signal in the directional coupler 51.

Referring to the operation and effects of the present invention configured as described above in detail. First, the airwave broadcasting signals inputted to the first antenna 11 and the second antenna 12 are combined by the combiner 13 and input to the tuning circuit 14. In this case, the control unit 20 may select one broadcast signal frequency by outputting a control voltage to the tuning circuit 14. The information about the control voltage is stored in the ROM 22 and then the central processing unit It is output to the tuning circuit 14 via the first latch section 24 'and the first DAC 24 in the order called by 21 so that the tuning frequency changes in time.

The broadcast signal tuned by the voltage control tuning circuit 14 is amplified by the broadcast signal amplifier 30, and the broadcast signal passing through the attenuator 31 and the preamplifier 32 is used by the divider 33 for broadband power. It is input to the amplifier 34 and the level detector 40 and outputs a level detection signal from the level detector 40.

Of course, the broadcast signal input from the divider 33 to the broadband power amplifier 34 is transmitted through the directional coupler 51 and the leaky coaxial cable 52. That is, the control voltage is changed in time to change the tuning frequency of the broadcast signal in time, and the level detector 40 detects the broadcast signal level of the tuning frequency and outputs the level detection signal to the controller 20. The broadcast signal level is stored in the RAM 23 through the ADC 25 and the second latch 25 '.

The central processing unit 21 repeats the above process and arranges the broadcast signal level for each tuning frequency in order of magnitude and stores it in the RAM 23, and a signal having a high broadcast signal level reduces gain. A signal having a small broadcast signal level increases the gain.

Thereafter, the central processing unit 21 outputs the gain control signal to the attenuator 31 and adjusts the broadcast signal level for each tuning frequency so that the input broadcast signal level is uniformly amplified.

The airwave signal input to the time-division modulation-type wideband amplification circuit of the present invention is not limited to AM and FM broadcast signals but can be applied to other radio frequencies such as PAGER, CELLULAR, and the like. Applicable when not partitioned or time-divided.

Of course, the signal input to the antenna is not limited to two flowcharts, but may be additionally used as necessary.

As described above, the present invention includes a broadcast signal input unit, a control unit, a broadcast signal amplifier, a level detector, and a broadcast signal output unit to sequentially control a tuning frequency, a signal having a high broadcast signal level reduces a gain, and a signal having a small broadcast signal level By adjusting the gain for each tuning frequency by increasing the gain, the attenuation signal level of all tuning frequencies is adjusted to a uniform size and then amplified, thereby amplifying the broadcast signal clearly at the destination.

Claims (3)

A broadcast signal input unit to which an over-the-air broadcast signal is input; A control unit which outputs a control voltage signal for controlling a frequency channel to the broadcast signal input unit so that broadcast signals of various channels are input, and outputs a gain control signal to control an amplification gain rate of the input broadcast signal; A broadcast signal amplifier for amplifying the broadcast signal input by the gain control signal output from the controller to a different amplification by applying a selective amplification degree; A level detector for detecting a level of the broadcast signal amplified by the broadcast signal amplifier and feeding back a level detection signal to the controller; And a broadcast signal output unit configured to output the broadcast signal amplified by the broadcast signal amplifier. The method of claim 1, The broadcast signal input unit may include a first antenna and a second antenna to which the same air wave broadcast signal is input; A combiner for combining the broadcast signals inputted through the first and second antennas; And a voltage control tuning circuit for selecting a channel input by the control voltage output from the control unit. The method of claim 1, The control unit and the central processing unit, A first latch unit and a first DAC for outputting a control voltage stored in a ROM to the broadcast signal input unit under control of the central processing unit; A second latch unit and an ADC which receive the level detection signal output from the level detector and store the RAM under the control of the CPU; A third latch unit and a second DAC under the control of the central processing unit and outputting a gain control signal to the broadcast signal amplifier; And a decoder configured to output a clock signal to the first, second and third latch units under the control of the central processing unit.