KR100826456B1 - Analog broadcast receiver - Google Patents

Abstract

The present invention relates to a receiving apparatus including a tuner IC (MOPLL IC) and a demodulation IC, wherein a control signal used to select an intermediate frequency in the demodulation IC according to a broadcasting method is provided from a surplus terminal of the mole IC. Accordingly, the present invention relates to an analog broadcast receiving apparatus capable of eliminating the inconvenience of providing a control signal from the outside. According to the present invention, a tuner having a plurality of redundant output terminals generating an intermediate frequency of a selected channel from a signal received from an antenna and outputting a high signal corresponding to a power supply voltage or a low signal corresponding to ground IC and the intermediate frequency are demodulated to detect a video signal and an audio signal of a baseband, and have a plurality of broadcasting method determination input terminals corresponding to each of the plurality of redundant output terminals, and according to the high signal or low signal. The present invention provides an analog broadcast receiver including a demodulation IC in which a broadcast method is determined by determining an electrical state of an input terminal.

Description

Analog broadcast receiver {APARATUS FOR RECEIVING ANALOG BROADCAST}

1 is a block diagram illustrating a conventional analog broadcast receiver.

2 is a block diagram illustrating an analog broadcast receiver according to the present invention.

3 is a diagram showing the pin configuration of the tuner IC (SN761677DBT) that can be employed in the present invention.

4 and 5 are circuit diagrams showing the structure of the redundant output terminal of the tuner IC shown in FIG.

Fig. 6 shows a pin configuration of a demodulation IC (TDA9882) that can be employed in the present invention, and a switch for controlling the broadcast method determination terminal of the demodulation IC.

* Description of the symbols for the main parts of the drawings *

11: Micom 12: Tuner IC

121: redundant output terminal 13: demodulation IC

14a, 14b: filter ANT: antenna

The present invention relates to a receiving apparatus for receiving an analog broadcast, and more particularly, to a receiving apparatus including a tuner IC and a demodulation IC, the control signal being used to select an intermediate frequency in the demodulation IC according to a broadcasting method. The present invention relates to an analog broadcast receiver capable of eliminating the inconvenience of providing a control signal from the outside by providing the redundant terminal of the mother IC.

In general, a receiver for receiving an analog broadcast selects a frequency of a desired channel from a signal input from an antenna and converts the frequency into an intermediate frequency signal, and demodulates the intermediate frequency signal to a baseband signal having original video information and audio information. Detecting and outputting the device.

1 is a block diagram showing a conventional analog broadcast receiving apparatus. As shown in FIG. 1, a conventional analog broadcast receiving apparatus includes a tuner IC (or MOPLL IC) for selecting a frequency of a desired channel from a signal input from an antenna ANT, converting it into an intermediate frequency signal, and outputting the intermediate frequency signal. A demodulation IC for demodulating an intermediate frequency (IF) signal output from the tuner IC 120 to detect and output baseband signals Sv and Ss having original video information and audio information ( 130, and filters 140a and 140b disposed between the antenna ANT and the tuner IC 120 and between the tuner IC 120 and the demodulation IC 130.

In the analog broadcast reception device as described above, when a channel selection signal for selecting a frequency of a corresponding selection channel from the microcomputer 110 is input to the tuner IC 120 according to a channel selection input by a user, the tuner IC 120 is input to the tuner IC 120. The frequency of the selected channel among the input frequencies is converted into the intermediate frequency and output. The demodulation IC 130 demodulates an intermediate frequency signal output from the tuner IC 120 to detect and output a baseband video signal Sv and an audio signal Ss.

Meanwhile, the demodulation IC 130 is developed to be used in various analog broadcasting methods such as NTSC, PAL, SECAM, etc., and accordingly, the demodulation IC 130 may have an input terminal for selecting each broadcasting method. That is, various analog broadcasting methods use different intermediate frequencies, and the demodulation IC 130 has a plurality of input terminals for selecting a broadcasting method currently used to demodulate intermediate frequencies used in each analog broadcasting. Have In FIG. 1, control signals for selecting a broadcasting scheme are indicated by Vc1 and Vc2. The control signals Vc1 and Vc2 are a combination of an open or ground state of a plurality of input terminals for selecting a broadcasting method by selectively opening or grounding a plurality of input terminals for selecting a broadcasting method of the demodulation IC 130. Various broadcasting methods can be selected.

Conventionally, a method of receiving a control signal for selecting a broadcast method in which the demodulation IC 130 is used starts from a set in which a receiver is installed. That is, in the related art, a structure in which a broadcast method selection control signal of the demodulation IC 130 is input from the outside of the broadcast receiving device is adopted. Therefore, a separate signal connection line is required between the analog broadcast receiver and the set, which may cause a problem in that the design complexity increases. Even when a user needs to select a broadcasting method by using a physical switch directly, a problem may be seriously degraded.

The present invention has been proposed to solve the above-described problems of the related art, and its object is to control the broadcast signal of the demodulation IC from the outside by determining the broadcast method of the demodulation IC internally. An analog broadcast receiving device is provided.

The present invention to achieve the above object,

A tuner IC for generating an intermediate frequency of a selected channel from a signal received from an antenna and having a plurality of redundant output terminals for outputting a high signal corresponding to a power supply voltage or a low signal corresponding to ground; And

The video signal and the audio signal of the baseband are detected by demodulating the intermediate frequency, and have a plurality of input methods for determining a broadcasting method corresponding to each of the plurality of redundant output terminals, and the input terminal according to the high signal or the low signal. Demodulation IC determines broadcast method by determining electrical state

It provides an analog broadcast receiving apparatus comprising a.

An embodiment of the present invention may further include a plurality of switches for opening or grounding the plurality of broadcasting method determination input terminals, respectively, according to the high or low signal.

Preferably, the tuner IC may employ a SN761677DBT of Texas Instruments, and the redundant output terminal of the SN761677DBT implemented as an emitter follower of the P5 to P6 output terminal of the SN761677DBT or the NPN transistor implemented as an open collector of an NPN transistor. It may be a BS1 to BS4 output terminal.

Preferably, as the demodulation IC, Philips TDA9882 may be adopted, and the broadcasting terminal input terminal may be a QSSO terminal, a VIF0 terminal, an FM0, and an FM1 terminal of the TDA9882.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiment of this invention is provided in order to demonstrate this invention more completely to the person skilled in the art to which this invention belongs. In addition, in the description of the present invention, terms defined are defined in consideration of functions in the present invention, which may vary according to the intention or convention of those skilled in the art, and thus limit the technical components of the present invention. It should not be understood as meaning.

2 is a block diagram illustrating an analog broadcast receiver according to the present invention.

Referring to FIG. 2, the analog broadcast reception device according to the present invention includes a tuner IC 12 having a redundant output terminal 121 and a demodulation IC 13 having an input terminal for determining a broadcast method. In addition, the analog broadcast receiving apparatus of the present invention includes an antenna ANT, a filter 14a disposed between the antenna ANT and the tuner IC 12, and between the tuner IC 12 and the demodulation IC 13. It may further include a filter 14b disposed in.

The tuner IC 12 converts the frequency corresponding to the channel selected by the user from the RF signal input from the antenna to the intermediate frequency IF. More specifically, a signal corresponding to a user's channel selection is input to a set of microcomputers 11, such as a TV or a VCR employing an analog broadcast receiver, and the microcomputer 11 typically uses a tuner IC using an I2C communication method. Information about the selected channel is transmitted to 12. Subsequently, the tuner IC 12 generates an appropriate oscillation frequency using a phase locked loop circuit to convert the frequency of the selected channel input from the microcomputer 11 into an intermediate frequency, and then synthesizes it with the RF signal input from the antenna. Generates the median frequency of the channel.

The tuner IC 12 is an oscillator for generating an oscillation frequency synthesized with an input RF signal, a mixer for synthesizing the oscillation frequency with the RF signal, and for generating the oscillation frequency to a desired value. It is also commonly referred to as a MOPLL IC because it includes a phase locked loop circuit (PLL).

The tuner IC 12 of the present invention further includes a redundant output terminal that can be applied to other applications in addition to a terminal necessary for converting an input RF signal to an intermediate frequency. The surplus output terminal is a terminal for outputting a high signal corresponding to a power supply voltage or a low signal corresponding to ground.

3 is a diagram showing the pin configuration of the 'SN761677DBT' chip of Texas Instruments, a tuner IC that can be employed in the present invention.

Looking at the main terminal (or pin) of the SN761677DBT chip with reference to Figure 3, first, terminals 35 to 38 are the terminals to which the RF signal is input from the antenna, and terminals 11 and 12 are the terminals where the converted intermediate frequency is output. to be. In addition, terminals 22 and 23 are terminals applied to I2C communication with the microcomputer 11, terminal 22 is a clock signal, and terminal 23 is a terminal for transmitting data. Also, terminals 20, 21, 25, and 27 to 31 may be used as redundant output terminals for outputting a high signal or a low signal in the present invention.

Terminals 20, 21, 25, and 27 of the terminals used as redundant output terminals in the SN761677DBT chip are named P8, P7, P6, and P5, respectively, and as shown in FIG. 4, the NPN transistor Q1 Implemented as an open collector. That is, when the high signal is input to the gate of the NPN transistor Q1 and the NPN transistor Q1 is turned on, a low signal corresponding to the ground state is output to the P8, P7, P6, and P5 terminals, and the NPN transistor ( When Q1) is off, the terminal is open.

In addition, terminals 28 to 31 of the terminals used as redundant output terminals in the SN761677DBT chip are named BS4, BS3, BS2, and BS1, respectively, and as shown in FIG. 5, the emitter follower of the NPN transistor Q2 ( implemented as an emitter follower). That is, when the NPN transistor Q2 is turned on, a high signal corresponding to the power supply voltage Vcc is output, and when the NPN transistor Q2 is turned off, the terminal is grounded through the resistor R.

Determination of the on / off state of the NPN transistors Q1 and Q2 internally connected to the surplus output terminals in the SN761677DBT chip includes information on the broadcasting scheme transmitted from the microcomputer 11 and the demodulation IC 13 described below. It may be determined according to the electrical state setting of the terminal for determining the broadcast method.

The demodulation IC 13 demodulates an intermediate frequency output from the tuner IC 12 to detect a baseband video signal Sv and an audio signal Ss. The demodulation IC 13 applied to the present invention is a demodulation IC that can be applied to various broadcasting systems such as NTSC, PAL, SECAM, and the like, and is a demodulation IC that needs to be set for the broadcasting system that is applied. The demodulation IC 13 of the present invention has a plurality of broadcast method determination input terminals respectively corresponding to the surplus output terminals of the tuner IC 12 for setting the broadcast method to be applied. The plurality of broadcast method determination input terminals may determine a broadcast method to be used according to a combination of electrical states. For example, if the demodulation IC 13 has four broadcasting system determination input stages, the NTSC broadcasting system is used when the electrical states of the four broadcasting system determination input stages are [open, open, open, open]. If the electrical states of the four broadcast method determination input terminals are [open, ground, ground, open], it may be determined that the present invention is applied to the PAL broadcast.

FIG. 6 is a diagram illustrating a pin configuration of a TDA9882 chip manufactured by Philips, a demodulation IC that can be employed in the present invention, and a switch for controlling a broadcast method determination terminal of the demodulation IC.

Referring to the main terminals (or pins) of the TDA9882 chip with reference to FIG. 6, first, terminals 1, 2, 23, and 24 are terminals to which an intermediate frequency is input, and terminals 8 and 17 are demodulated bases, respectively. The audio signal Ss and the video signal Sv of the band are output. In addition, four terminals of Nos. 10 to 13 are terminals used in determining a broadcasting scheme to which the demodulation IC 13 is applied in the present invention. The specification for the TDA9882 chip provided by Philips, a manufacturer of the TDA9882 chip, provides a terminal selection table for selecting an image intermediate frequency and an audio carrier frequency as shown in Tables 1 and 2 below.

QSSO (terminal 12) VIF0 (terminal 13) Video intermediate frequency (MHz) No resistance connection at the terminals Opening 45.75 No resistance connection at the terminals grounding 38.9 Ground via 2.2㏀ resistor Opening 33.9 Ground via 2.2㏀ resistor grounding 38.9

FM0 (terminal 11) FM1 (terminal 10) Voice carrier frequency (MHz) Opening Opening 4.5 grounding Opening 5.5 Opening grounding 6.0 grounding grounding 6.5

As shown in Table 1 and Table 2, it is possible to select the intermediate frequency and the audio carrier frequency used in the image by various combinations of the electrical state of the terminals 10 to 12, which is a terminal for determining the broadcast method of the TDA9882 chip. Since the intermediate frequency and the audio carrier frequency of the video are determined according to the broadcasting method, the broadcasting method to which the TDA9882 chip, that is, the demodulation IC 13 is applied, is determined by determining the electrical state of terminals 10 to 12 of the TDA9882 chip. It becomes possible. For example, the NTSC method uses an image intermediate frequency of 45,75 MHz and an audio carrier frequency of 4.5 MHz, so that the QSSO terminal (terminal 12) is opened, VIF0 (terminal 13) is opened, and FM0 (11 Terminal 1) and FM1 (terminal 10) can be opened so that the demodulation IC 13 can be applied to NTSC broadcast reception.

Meanwhile, in the present invention, an input terminal for determining a broadcast method of the demodulation IC 13 corresponds to a surplus output terminal of the tuner IC 12, respectively, and is high or low output from the surplus output terminal of the tuner IC 12. The electrical state of the input terminal for determining the broadcast method of the demodulation IC 13 is determined by the signal. A high or low signal output from the excess output terminal of the tuner IC 12 may be directly applied to an input terminal for determining a broadcast method of the demodulation IC 13, and an additional switch may be added to the demodulation IC 13 as necessary. The input method for determining the broadcast method of the demodulation IC 13 by controlling the state of the switch to a high or low signal output from the excess output terminal of the tuner IC 12. The electrical state of the can be determined.

FIG. 6 shows an example in which the switches SW1 to SW4 are applied to the broadcasting terminal determination input terminal of the demodulation IC 13. For example, P8 terminal 20 of the SN761677DBT chip of FIG. 3 is connected to a switch (SW1) connected to QSSO terminal 12 of the TDA9882 chip, and BS3 terminal 29 of the SN761677DBT chip is 13 of the TDA9882 chip. Terminal 7 of the SN761677DBT chip is connected to the switch (SW2), which is connected to the switch (SW2) connected to the FM0 terminal, which is terminal 11 of the TDA9882 chip, and terminal 25 of the SN761677DBT chip. It is assumed that the P6 terminal is connected to the switch SW4 connected to the FM1 terminal of the TDA9882 chip so that each switch SW1 to SW4 is controlled by the output signal of the surplus output terminal of the SN761677DBT chip. In addition, the switch SW1 connected to the QSSO terminal, the switch SW3 connected to the FM0 terminal, and the switch SW4 connected to the FM1 terminal are opened when a low signal corresponding to ground is input, for example, a gate. Is assumed to be an NPN transistor in which the collector and emitter are open, and the switch (SW2) connected to the VIF0 terminal is a switch that is open in a high state, for example a collector when the gate is high. Assume a PNP transistor with the and emitter open.

If the TDA9882 chip, which is the demodulation IC 13, is used in the NTSC system, as shown in Tables 1 and 2 above, all terminals for determining the broadcast method of the TDA9882 chip should be opened. When the microcomputer 11 transmits information to the tuner IC 12 that the broadcast method to be currently received is NTSC, the internal NPN transistor of the P8 terminal, which is the 20th terminal of the SN761677DBT chip of the tuner IC 12 (FIG. 4). Q1) is turned on, and the P8 terminal outputs a low signal corresponding to ground, and the internal NPN transistor (Q2 of FIG. 5) of the BS3 terminal, which is the 29th terminal of the SN761677DBT chip, is turned on so that the BS3 terminal corresponds to the power supply voltage. A high signal is outputted, and the internal NPN transistor (Q1 of FIG. 4) of the P7 terminal, which is the 21st terminal of the SN761677DBT chip, is turned on so that the P7 terminal outputs a low signal corresponding to ground, and is the 25th terminal of the SN761677DBT chip. The internal NPN transistor (Q1 of FIG. 4) of the P6 terminal is turned on so that the P6 terminal outputs a low signal corresponding to ground. The switches SW1 to SW4 are all opened by the output signals of the surplus output terminals of the SN761677DBT chip, and the terminals for determining the broadcasting method of the TDA9882 chip, which is the demodulation IC 13, are electrically open. The setting applicable to the broadcast reception of the scheme is completed.

Although the above description has been mainly based on the setting of the demodulation IC for NTSC broadcast reception as an example, the present invention is not limited thereto, and the derivation of a setting that can be applied to other broadcast methods is described with reference to Tables 1 and 2 above. Since a person skilled in the art can easily implement, a detailed description of an example applied to another broadcasting method will be omitted.

As described above, according to the present invention, the broadcast of the demodulation IC is performed by internal processing of the receiver without requiring a control signal provided from the outside of the analog broadcast receiver including the tuner IC and the demodulation IC to determine the broadcast method of the demodulation IC. Since the method can be set, there is no need for a separate signal connection line between the analog broadcast receiver and the set, thereby preventing an increase in design complexity.

In addition, since a plurality of switch operations for determining the broadcast method of the demodulation IC can be omitted by the user, the user's convenience can be increased.

Claims (4)

A microcomputer receiving a channel selection signal of a user and outputting information on the selected channel and information on a broadcast method to be received; Generates an intermediate frequency of the selected channel from the signal received from the antenna according to the information on the selected channel, and a high signal corresponding to a power supply voltage or a low corresponding to ground according to the information on the broadcasting method. A tuner IC having a plurality of surplus output terminals for outputting a signal; And The video signal and the audio signal of the baseband are detected by demodulating the intermediate frequency, and have a plurality of input methods for determining a broadcasting method corresponding to each of the plurality of redundant output terminals, and the input terminal according to the high signal or the low signal. Demodulation IC determines broadcast method by determining electrical state Analog broadcast receiving device comprising a. The method of claim 1, And a plurality of switches for respectively opening or grounding the plurality of broadcast mode determination input terminals according to the high or low signal. The method of claim 1, The tuner IC is SN761677DBT of Texas Instruments, And the redundant output terminal is a P5 to P6 output terminal implemented as an open collector of an NPN transistor or a BS1 to BS4 output terminal implemented as an emitter follower of an NPN transistor. The method of claim 1, The demodulation IC is Philips TDA9882, The input method for determining the broadcast method is an analog broadcast receiver, characterized in that the QSSO terminal, VIF0 terminal, FM0, FM1 terminal.

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