KR0134451B1 - Apparatus for recording the signal in the full auto search - Google Patents

Abstract

The present invention relates to a strong signal selective recording apparatus for full auto search according to the present invention, wherein a plurality of channel method RF (Radio Frequency) signals are sequentially inputted and outputted, and an automatic gain control voltage of the inputted RF signal is provided. An AGC unit 200 for calculating and outputting an automatic gain control voltage, an RF signal inputted in the same manner as the AGC unit 200, and a detection unit 222 for outputting a determination signal in response to the AGC voltage input; A first resistor R1 having one end connected to the output terminal of the AGC unit 200 and an anode terminal connected to the other end of the first resistor R1 have an automatic gain control voltage output from the AGC 200. The cathode stage of the Zener diode Z1 and the Zener diode Z1 which are turned off when the value is less than the preset value Th and turned on when the automatic gain control voltage output from the AGC unit 200 is greater than or equal to the preset value Th N-type ground with the base connected to the emitter The second resistor R2 connected between the jitter Q1, the collector terminal of the N-type transistor Q1, and the detector 222 and the second resistor R2 when the N-type transistor Q1 is turned off. The control unit 240 outputs a control signal in response to the determination signal of the detection unit 222 provided via the N-type transistor Q1, and the RF signal in the same way as the AGC unit 200. A digital signal provided from the converter 260 in response to a control signal provided from the converter 260 for converting the frequency of the input RF signal into a digital signal and outputting the digital signal. And a memory unit 280 for recording signals for each channel.

Description

Strong signal selective recording device for TV full auto search

1 is a flowchart for schematically illustrating a strong signal selective recording method based on the strong signal selective recording apparatus of the present invention.

2 is a block diagram showing a strong signal selective recording apparatus according to a preferred embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

200: AGC unit 220: judgment unit

222: detector 224: detector

240 control unit 260 conversion unit

280: memory

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to television full auto search, and more particularly, to a strong signal selective recording apparatus in television full auto search.

In general television including cable television (CA TV), the function of automatically searching for and recording the frequency of the RF (Radio Frequency) signal inputted by a plurality of different channels during initial operation is full auto search (Full Auto). Search).

In general, in a full auto search of a television, an RF signal of 30 dB or more can be detected, and an RF signal of 50 dB or more is recognized as a strong signal.

At this time, the strong signal is in a state that can be viewed on a clear screen, while the weak signal is not. Therefore, since a channel to which a weak signal is input is almost impossible to watch television, a channel to which a weak signal is input is hardly selected when watching a broadcast program.

By the way, in the conventional television, the frequency search is performed for all the channels, so that the frequencies for each channel are sequentially recorded in the memory unit. Therefore, the weak signal and the strong signal input channel are recorded in a mixed state in the memory unit, which has a big problem of being very inefficient in selecting a channel.

Accordingly, an object of the present invention is to provide an apparatus capable of channel selection more efficiently by selectively recording only the frequencies of the strong signals that are substantially viewable in television full auto search.

The present invention, in order to achieve the above object, by sequentially inputting and outputting a plurality of RF (Radio Frequency) signal for each channel, AGC unit for calculating and outputting the automatic gain control voltage (Automatic Gain Control Voltage) of the input RF signal Wow; A detection unit for inputting an RF signal in the same way as the AGC unit and outputting a determination signal in response to the AGC voltage input, and a first resistor having one end in contact with an output terminal of the AGC unit 200 and the other end of the first resistor. A zener diode connected to the cathode terminal and turned off when the automatic gain control voltage output from the AGC unit is less than a predetermined value, and turned on when the automatic gain control voltage output from the AGC unit is greater than or equal to a predetermined value; A base end is connected to an anode end of the base terminal, and a mater end is a grounded N-type transistor, a second resistor connected between the collector terminal of the N-type transistor and the detection unit, and when the N-type transistor is turned off, the second resistor and A control unit for outputting a control signal in response to a determination signal of the detection unit provided via the collector terminal of the N-type transistor, and an RF signal as in the AGC unit. And a converter for converting the frequency of the input RF signal into a digital signal and outputting the digital signal, and a memory unit for recording the digital signal provided from the converter for each channel in response to a control signal provided from the controller. It is characterized by.

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

FIG. 1 is a flowchart for schematically explaining an operation of a strong signal selective recording apparatus in a TV full auto search according to the present invention, and sequentially inputting a plurality of radio frequency (RF) signals for each channel (100). And 120, calculating the automatic gain control voltage of the RF signal input in step 100, and the automatic gain control voltage calculated in step 120. If the automatic gain control voltage calculated in step 140 compares with the preset value Th and the result of the step 140 is less than the preset value Th, input is performed for each channel in step 100. And determining that the received RF signal is a strong signal, and recording the frequency of the RF signal for each channel input in step 100 for each channel in the memory unit.

FIG. 2 (a) is a block diagram showing the operation of the strong signal selective recording apparatus in the TV full auto search according to the preferred embodiment of the present invention. The AGC (Automatic Gain Control) unit 200, the determination unit 220, a control unit 240, a conversion unit 260, and a memory unit 240.

The AGC unit 200 sequentially inputs and outputs a plurality of radio frequency (RF) signals for each channel, and calculates and outputs an automatic gain control voltage of the input RF signal.

The determination unit 220 includes a detector 222 and a detector 224. The detector 222 inputs an RF signal in the same manner as the AGC unit 200, and outputs a determination signal to the detector 224 in response to the AGC voltage input, and the detector 224 from the AGC unit 200. Only when the AGC voltage provided is lower than the preset value Th, the determination signal provided from the detector 222 is output to the controller 240.

The control unit 240 outputs a control signal in response to the determination signal provided from the determination unit 200.

The changer 260 inputs an RF signal in the same manner as the AGC unit 200, and converts the frequency of the input RF signal into a digital signal and outputs the digital signal.

The memory unit 280 records the digital signal provided from the converter 260 for each channel in response to the determination signal provided from the controller 240.

FIG. 2 (b) shows the detection unit 214 shown in FIG. 2 (a) in more detail, and is connected in series between the transistor Q1 AGC unit 200 and the base of the transistor Q1. And a resistor R2 connected between the resistor R1 and the zener diode Z1 and the collector terminal of the transistor Q1 and the detector 222, and the collector terminal of the transistor Q1 is connected to the control unit 240. do.

A strong signal selective recording apparatus in a television full auto search according to the present invention configured as described above will be described in more detail with reference to FIG.

First, the RF signal for any one of the plurality of channels is input to the AGC unit 200 (step 100). The AGC unit 200 calculates the AGC voltage of the input RF signal and outputs the AGC voltage to the detection unit 224 (step 120). Here, the AGC voltage calculation process of the RF signal is already well known and will be omitted.

In this case, the RF signal is divided into a weak signal or a strong signal according to the frequency, and the AGC voltage also varies according to the weak signal or the strong signal. In the present invention, the weak signal exemplarily refers to an RF signal of less than 50 dB, and the AGC voltage at this time is about 8 to 10V. On the other hand, the strong signal is for example an RF signal of 50dB or more, the AGC voltage at this time is about 4 to 6V.

When a strong signal is input, the Zener diode Z1 is opened in an open state by an AGC voltage of 4 to 6 V, and a low level signal is applied to the base of the transistor Q1. Accordingly, the transistor Q1 is turned off and the collector terminal receives the determination signal provided from the detector 222.

In response to the determination signal provided through the collector terminal of the transistor Q1, the controller 240 outputs a control signal to the memory unit 280.

On the other hand, when a weak signal is input, the zener diode Z1 is short-circuited by an AGC voltage of 8 to 10V, and a high hevel signal is applied to the base of the transistor Q1. Therefore, the transistor Q1 is turned on and the collector terminal receives a low level signal. Therefore, no change occurs in the controller 240. In other words, the controller 240 does not output a control signal.

Meanwhile, the converter 260 inputs an RF signal in the same manner as the AGC unit 200. The converter 260 converts the input RF signal into a digital signal and outputs the RF signal to the memory unit 280.

In this case, the memory unit 280 records the digital signal provided from the converter 260 for each channel only when the determination signal is provided from the controller 240.

As a result, the strong signal selective recording apparatus in the television full auto search according to the present invention selectively records only the frequency of the strong signal among the input RF signals, which is very effective in selecting a channel.

Claims (1)

An AGC unit 200 for sequentially inputting and outputting a plurality of radio frequency (RF) signals for each channel, and calculating and outputting an automatic gain control voltage of the input RF signal; A detector 222 for inputting an RF signal in the same manner as the AGC unit 200 and outputting a determination signal in response to the AGC voltage input; A first resistor R1 having one end connected to an output terminal of the AGC unit 200; A cathode terminal is connected to the other end of the first resistor R1, and when the automatic gain control voltage output from the AGC unit 200 is less than a preset value Th, the cathode is turned off and output from the AGC unit 200. A zener diode Z1 that is turned on when the automatic gain control voltage is greater than or equal to a preset value Th; An N-type transistor Q1 having a base terminal connected to the anode terminal of the zener diode Z1 and an emitter terminal grounded; A second resistor R2 connected between the collector terminal of the N-type transistor Q1 and the detector 222; When the N-type transistor Q1 is turned off, a control signal is output in response to the determination signal of the detection unit 222 provided through the collector terminal of the second resistor R2 and the N-type transistor Q1. A control unit 240 and a conversion unit 260 for inputting an RF signal similarly to the AGC unit 200 and converting the frequency of the input RF signal into a digital signal and outputting the digital signal; In response to the control signal provided from the control unit 240, a strong signal in a full auto search (Full Auto Search) including a memory unit 280 for recording the digital signal provided from the conversion unit 260 for each channel Optional recorder.