KR20100127355A - Digital / Analog Broadcasting Receiver - Google Patents

Abstract

The present invention relates to a digital / analog broadcast receiver capable of receiving both a digital broadcast signal and an analog broadcast signal, wherein the receiver receives a digital broadcast signal and an analog broadcast signal, and among the received RF broadcast signals. Selecting a desired RF signal of a specific channel and converting it into an IF signal, and through a tuner unit for selectively outputting the converted IF signal to a digital channel or an analog channel according to the input control signal, and through the digital channel or analog channel of the tuner unit A demodulator for demodulating the input digital or analog IF signal into a baseband signal, and an analog filter embedded in the demodulator and selectively passing a signal of a desired frequency band among analog IF signals input through the analog channel; It includes;

Description

Digital / Analog Broadcasting Receiver {DIGITAL / ANALOG BROADCASTING RECEIVING APPARATUS}

The present invention relates to a broadcast receiver, and more particularly, to a digital / analog broadcast receiver capable of receiving both a digital broadcast signal and an analog broadcast signal.

At present, digitalization of television broadcasting such as digital satellite broadcasting and digital terrestrial broadcasting is rapidly progressing, and then the transition from analog broadcasting to digital broadcasting will be fully progressed.

However, even if digitalization of television broadcasting proceeds, existing analog broadcasting does not stop immediately. For this reason, in the transition period from analog broadcast to digital broadcast, analog broadcast and digital broadcast coexist.

As described above, when both analog broadcast and digital broadcast are serviced, a broadcast receiver capable of receiving both analog broadcast and digital broadcast is desired.

An object of the present invention is to provide a digital / analog broadcast receiver capable of realizing slimming and assembling of a product by modularizing a receiver for receiving both a digital broadcast signal and an analog broadcast signal.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the following description. There will be.

In order to achieve the above object, the receiving apparatus of the present invention receives a digital broadcast signal and an analog broadcast signal, selects a desired RF signal of a specific channel among the received RF broadcast signals, converts the IF signal, and converts the converted IF signal. A tuner unit selectively outputting a digital channel or an analog channel according to an input control signal; A demodulator for demodulating the digital or analog IF signal input through the digital or analog channel of the tuner into baseband signals, respectively; And an analog filter unit built in the demodulator and selectively passing a signal of a desired frequency band among analog IF signals input through the analog channel.

Specifically, the tuner unit includes a local oscillator for generating a local signal for channel tuning for the selected channel under the control of the controller; A mixer for synthesizing the inputted RF signal and the local signal for the selected channel inputted from the local oscillator and down converting them into the required IF signal; And a band pass filter for outputting a signal having a desired frequency band by removing adjacent channels and noise of the received signal among the IF signals input from the mixer. And a path selector configured to variably control an output channel according to an input control signal to output an IF signal input from the band pass filter to a digital channel or an analog channel.

As described above, the receiver according to the present invention has a tuner unit with a path selector installed therein, and a demodulator with a built-in analog filter unit can be installed to simplify the manufacture and assembly of the analog and digital receiver. There is an advantage to reduce the production cost accordingly.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. Like elements in the figures are denoted by the same reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 is a diagram illustrating a digital / analog broadcast receiver according to the present invention, wherein the receiver 1 includes a tuner unit 10, an analog filter unit 30, and a demodulator 50.

The tuner unit 10 includes a first gain control amplifier 12, a local oscillator 13, a mixer 14, a digital filter 15, and a second gain control amplifier 16. 10 is an analog / digital common for selecting an RF signal of a specific channel selected by a user among RF broadcast signals input through the antenna 11 and converting the selected RF signal into a signal of an intermediate frequency band (IF signal) and outputting the signal. to be.

The first gain control amplifier 12 automatically adjusts and outputs the gain of the RF signal received by the antenna 11 according to the control signal.

The local oscillator 13 is composed of a VCO that generates a local signal LO1 for channel tuning in accordance with the control signal. The local signal varies in frequency depending on the channel selected by the user.

The mixer 14 synthesizes the RF signal input from the first gain control amplifier and the local signal LO1 for the selected channel input from the local oscillator and down-converts the required intermediate frequency signal (IF signal) to output.

The digital filter 15 outputs a signal of a desired frequency band by removing an adjacent channel and noise of a received signal among the IF signals input from the mixer 14. The digital filter 15 is a band pass filter and is composed of a SAW filter having excellent filtering performance.

The second gain control amplifier 16 automatically adjusts and outputs an IF signal input from the digital filter 15 according to a control signal.

The analog filter unit 30 includes a video filter 31 and an audio filter 32. Each of the filters 31 and 32 filters adjacent channels and noises of the received signals among the IF signals input from the mixer 14. It removes and outputs signals of desired video and audio frequency bands. The analog filters 31 and 32 are band pass filters and are composed of SAW filters having excellent filtering performance.

The demodulator 50 includes a switching means 51, a digital demodulator 53, a third gain control amplifier 55, and an analog demodulator 57.

The switching means 51 is switched according to the control signal to determine whether to output the signal input from the second gain control amplifier 16 of the tuner unit 10.

The digital demodulator 53 demodulates the digital broadcast signal output from the tuner 10 through the switching unit 51 into a baseband signal and outputs the demodulated signal.

The third gain control amplifier 55 automatically adjusts and outputs a gain for the analog video signal output through the analog video filter 31 according to the control signal. The first to third gain control amplifiers 12, 16, and 55 are AGC amplifiers.

The analog demodulator 57 demodulates and outputs the analog video and audio signals respectively input from the third gain control amplifier 55 and the analog audio filter 32 into baseband signals.

In the analog-digital combined receiver 1 configured as described above, the analog filter unit 30 is not installed in the tuner unit 10 or the demodulator 50, but is provided separately from the outside. This does not meet the trend of modularization of components, which takes up a large area during assembly and increases the assembly cost.

FIG. 2 is a diagram illustrating a digital / analog broadcast receiving apparatus according to the present invention, and FIG. 3 is a detailed circuit diagram of the path selector of FIG. 2 according to an embodiment of the present invention.

The receiver 1 includes a tuner unit 100 and a demodulator 200.

The tuner unit 100 may include a first gain control amplifier 110, a local oscillator 120, a mixer 130, a band pass filter 140, a path selector 150, and a second gain control amplifier 160. The tuner 100 receives a digital broadcast signal and an analog broadcast signal, but selects an RF signal of a desired specific channel among the RF broadcast signals received through the antenna 101, and then outputs an intermediate frequency signal (IF signal). And converts the IF signal into a digital channel or an analog channel selectively according to the input control signal.

The first gain control amplifier 110 automatically adjusts and outputs the gain of the RF signal received by the antenna 101 according to the control signal. The first gain control amplifier 110 is an AGC (Automatic Gain Control) amplifier.

The local oscillator 120 generates a local signal LO1 for channel tuning for the selected channel under the control of a controller (not shown). The local oscillator 120 may include a Voltage Controlled Oscillator (VCO) and a Frequency-Phase Locked Loop (FPLL). The local signal has a variable frequency according to a channel selected by a user.

The mixer 130 synthesizes the RF signal input from the first gain control amplifier 110 and the local signal for the selected channel input from the local oscillator 120 and down-converts the IF signal to the required IF signal. The mixer 130 may be configured in plurality, and at least one of an upconversion mixer, a downconversion mixer, and a quadrature mixer (I, Q signal) may be mixed.

The band pass filter 140 outputs a signal of a desired frequency band by removing an adjacent channel and noise of a received signal among the IF signals input from the mixer 130. The bandpass filter 140 may be configured as a surface acoustic wave (SAW) filter having excellent filtering performance. The band pass filter 140 may be implemented using an inexpensive LC filter, a ceramic filter, or an analog IC filter instead of an SAW filter. In the case of an SAW filter, the band pass filter 140 has excellent skirt characteristics, and thus, when removing an interference signal of an adjacent channel. This has the advantage of better properties than other inexpensive filters.

The path selector 150 variably controls the output line according to the control signal to selectively adjust the output path of the IF signal input from the band pass filter 140. The path selector 150 may be provided at an output terminal of the band pass filter 140 and may include a switch unit for selectively opening and closing the digital channel D_IF or the analog channels A_IF1 and A_IF2 according to a control signal.

The second gain control amplifier 160 receives the IF signal output from the band pass filter 140 through the path selector 150 and automatically adjusts and outputs the gain of the input IF signal according to the control signal. The second gain control amplifier 160 is an AGC amplifier.

The mixer 130 synthesizes the input RF signal and the local signal LO1 input from the local oscillator 120, downconverts the output signal, and outputs the downconverted IF signal to the bandpass filter 140. When the center frequency of the filtering band of the band pass filter 140 is 44 MHz, only the IF signal having a center frequency of 44 ± 3 MHz is passed among the IF signals input to the band pass filter 140.

The demodulator 200 includes a switching means 210, a digital demodulator 220, an analog filter 230, a third gain control amplifier 240, and an analog demodulator 250.

The switching means 210 is switched according to the control signal to determine whether to output the signal input from the second gain control amplifier 160.

The digital demodulator 220 receives the digital broadcast signal output from the tuner 100 through the switching means 210 and demodulates the signal into a baseband signal.

The analog filter unit 230 is composed of a video filter 231 and an audio filter 232, each filter 231, 232 is the adjacent channel and noise for the received signal of the IF signal output from the mixer 130 It removes and outputs signals of desired video and audio frequency bands. The analog filters 231 and 232 are band pass filters, and may be configured as SAW filters or LC filters having excellent filtering performance.

The third gain control amplifier 240 is an AGC amplifier that automatically adjusts the gain of the analog video signal input through the analog video filter 231 according to the control signal.

The analog demodulator 250 demodulates the analog video signal and the audio signal respectively input from the third gain control amplifier 240 and the analog audio filter 232 into baseband signals.

The receiver 1 configured as described above is amplified to a predetermined level by the first gain control amplifier 110 when an RF signal is received through the antenna 101.

The amplified RF signal is selected by the mixer 130 and the local oscillator 120, the broadcast channel of the desired frequency band, the RF signal of the selected channel is converted into an IF signal is input to the band pass filter 140.

In addition, the bandpass filter 140 is analog / digital common, and is required to have good characteristics when receiving analog broadcasts or receiving digital broadcasts.

That is, since the analog signal is AM modulated, it is required that the amplitude characteristics are good at the time of analog broadcast reception. On the other hand, since the digital broadcast signal is modulated by Quadrature Amplitude Modulation (QAM), Vertical Sideband Amplitude Modulation (VSB), Orthogonal Frequency Division Multiplex (OFDM), a good phase characteristic is required. Therefore, the band pass filter 140 is required to have both good amplitude characteristics and phase characteristics.

The output of the band pass filter 140 is selectively transferred to the second gain control amplifier 160 or the analog filter 230 of the demodulator 200 by a control signal applied to the path selector 150.

The second gain control amplifier 160 amplifies the IF signal input from the bandpass filter 140 to a predetermined level and supplies it to the digital demodulator 220 of the demodulator 200. 220 demodulates the input IF signal into a baseband signal by demodulating QAM, VSB, OFDM, and the like.

In addition, the analog filter unit 230 outputs only signals of a desired frequency band among the IF signals input through the path selector 150 to the analog demodulation unit 250. Each filter has a good amplitude characteristic as a SAW filter. Is required.

The analog demodulator 250 AM demodulates the analog broadcast signal to demodulate the NTSC video and audio signals.

As described above, the receiving apparatus according to the present invention has a built-in path selector 150 installed in the tuner unit 100 and an analog-digital combined receiver as the analog filter unit 230 is installed in the demodulator 200. The modularity of the device simplifies manufacturing and assembly and enables slimming of the receive set.

Meanwhile, the path selector 150 embedded in the tuner unit 100 may be configured as shown in FIG. 3, and the path selector 150 may include a first switch unit 151 and a second switch unit ( 152 and the third switch unit 153 is configured.

The first switch unit 151 is installed between the first output terminal of the band pass filter 140 and the first input terminal of the second gain control amplifier 160 and opens and closes the digital channel D_IF according to a control signal. And a second diode D2 disposed between the diode D1 and the first output terminal of the band pass filter 140 and the analog video filter 231 to open and close the analog channel A_IF1 according to a control signal. .

The second switch unit 152 is installed between the second output terminal of the band pass filter 140 and the second input terminal of the second gain control amplifier 160 to open and close the digital channel D_IF according to a control signal. And a fourth diode D4 disposed between the diode D3 and the second output terminal of the band pass filter 140 and the analog audio filter 232 to open and close the analog channel A_IF2 according to a control signal. .

The third switch unit 153 includes a transistor Q1 that is switched according to a control signal applied from the outside to control whether the operating power is supplied to the second gain control amplifier 160.

The IF signal output through the first output terminal and the second output terminal of the band pass filter 140 may be the same signal, but in some cases, may be an I signal and a Q signal having different phases. Here, the Q signal is a signal shifted by about 90 degrees with respect to the I signal.

In FIG. 3, the path selector 150 basically includes the first switch 151 and the second switch 152. However, if necessary, the path selector 150 includes one output terminal of the band pass filter 140. It is also possible to configure the selector 150 as a single switch unit.

Then, a detailed configuration of the circuit diagram of FIG. 3 is as follows.

First, in the first switch unit 151, a first capacitor C1 is connected between the first output terminal of the band pass filter 140 and the first node Nd1, and connects the first node Nd1 to a common node. Thus, a plurality of voltage dividing resistors R1 and R2 are provided between the high potential Vcc and the low potential GND. The first diode (D1) is installed between the first node (Nd1) and the second node (Nd2) in a reverse direction and determines the on and off of the digital channel according to the control voltage applied to the second node (Nd2). The second node Nd2 is connected to the control node Nd_ctrl to which the control signal is applied through the resistor R3. A second capacitor C2 is connected between the second node Nd2 and the first input terminal of the second gain control amplifier 160. It is installed in the forward direction between the first node (Nd1) and the third node (Nd3), which is an input terminal of the analog video filter 231, the on and off of the analog channel according to the control signal applied to the third node (Nd3) The second diode D2 to be determined is connected, and the third node Nd3 is connected to the control node Nd_ctrl to which the control signal is applied through the resistor R4.

In addition, in the second switch unit 152, a third capacitor C1 is connected between the second output terminal of the band pass filter 140 and the fourth node Nd4, and connects the fourth node Nd4 to a common node. Thus, a plurality of voltage dividing resistors R5 and R6 are provided between the high potential and the low potential. The third diode D3 is installed in the reverse direction between the fourth node Nd4 and the fifth node Nd5 and determines the on / off of the digital channel according to the control voltage applied to the fifth node Nd5. The fifth node Nd5 is connected to the control node Nd_ctrl to which the control signal is applied through the resistor R7. A fourth capacitor C4 is connected between the fifth node Nd5 and the second input terminal of the second gain control amplifier 160. It is installed in the forward direction between the fourth node (Nd4) and the sixth node (Nd6) that is the input terminal of the analog audio filter 232 and determines the on and off of the analog channel according to the control signal applied to the sixth node (Nd6). The fourth diode D4 is connected, and the sixth node Nd6 is connected to the control node Nd_ctrl to which the control signal is applied through the resistor R8.

In addition, the third switch unit 153 has a current path connected between the high potential and the second gain control amplifier 160, and is opened and closed according to a control signal applied from the control node Nd_ctrl through the resistor R9. And a transistor (Q1) for supplying operating power to the gain control amplifier (160).

The control node Nd_ctrl is a node to which a control signal (control) applied from a controller (not shown) is supplied. When the control signal (control) applied to the control node (Nd_ctrl) is a high voltage, the digital channel is turned on. In addition, the analog channel is turned off, and when the control signal applied to the control node Nd_ctrl is low voltage, the analog channel is turned on and the digital channel is turned off.

That is, when a high voltage is applied to the control node Nd_ctrl, the first diode D1 is turned on because the second node Nd2 has a high potential compared to the first node Nd1, thereby turning on the digital channel. However, when a high voltage is applied to the control node Nd_ctrl, the third node Nd3 has a higher potential than the first node Nd1, so the second diode D2 is turned off to turn off the analog channel.

On the contrary, when a low voltage is applied to the control node Nd_ctrl, the third node Nd3 has a lower potential than the first node Nd1, so that the second diode D2 is turned on and the analog channel is turned on. However, when a low voltage is applied to the control node Nd_ctrl, the first diode D1 is turned off because the second node Nd2 has a low potential compared to the first node Nd1, so that the digital channel is turned off.

The third diode D3 and the fourth diode D4 are also operated in the same manner as the first diode D1 and the second diode D2.

As described above, the path selector 150 selectively adjusts output paths of the first switch unit 151 and the second switch unit 152 according to the input control signal to output the signal output from the band pass filter 140. It can be selectively delivered to digital or analog channels.

The present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. Could be. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

1 is a diagram showing a digital / analog broadcast receiver according to the present invention.

2 is a diagram illustrating a digital / analog broadcast receiver according to the present invention.

3 is a detailed circuit diagram illustrating a path selection unit of FIG. 2 according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

1: receiver 100: tuner section

110: first gain control amplifier 120: local oscillator

130: mixer 140: bandpass filter

150: path selector 151: first switch

152: second switch unit 153: third switch unit

160: second gain control amplifier 200: demodulation unit

210: switching means 220: digital demodulation unit

230: analog filter unit 240: third gain control amplifier

250: analog demodulation unit

Claims (10)

Receives digital broadcast signal and analog broadcast signal, selects RF signal of specific channel among received RF broadcast signal and converts into IF signal, and converts converted IF signal into digital channel or analog channel according to input control signal A tuner unit for outputting; A demodulator for demodulating the digital or analog IF signal input through the digital or analog channel of the tuner into baseband signals, respectively; And And an analog filter unit embedded in the demodulator and selectively passing a signal of a desired frequency band among analog IF signals input through the analog channel. The method of claim 1, The analog filter unit includes a plurality of filters for respectively filtering the video signal and the audio signal of the IF signal input through the analog channel, the plurality of filters are SAW filter digital / analog broadcast receiving apparatus. The method of claim 1, The tuner unit comprises a local oscillator for generating a local signal for channel tuning for the selected channel under the control of the controller; A mixer for synthesizing the inputted RF signal and the local signal for the selected channel inputted from the local oscillator and down converting them into the required IF signal; And a band pass filter for outputting a signal having a desired frequency band by removing adjacent channels and noise of the received signal among the IF signals input from the mixer. And a path selector configured to variably control an output channel according to an input control signal to selectively output an IF signal input from the band pass filter to a digital channel or an analog channel. The method of claim 3, wherein And the mixer comprises at least one of an upconversion mixer, a downconversion mixer, and a quadrature mixer. The method of claim 3, wherein And the path selector is provided at an output terminal of the band pass filter and includes a switch unit configured to open or close a digital channel or an analog channel according to a control signal. The method of claim 5, The switch unit may include: a first diode installed at an output terminal of the band pass filter and opening and closing a digital channel according to a control signal; And a second diode installed at an output end of the band pass filter and opening / closing an analog channel according to a control signal. The method of claim 3, wherein The band pass filter is a SAW filter digital / analog broadcast receiver. The method of claim 3, wherein And a gain control amplifier for automatically adjusting the gain of the IF signal output from the band pass filter through the path selection unit according to a control signal. The method of claim 3, wherein the path selector, A first diode installed at a first output end of the band pass filter and opening and closing a digital channel according to a control signal, and a second diode provided at a first output end of the band pass filter and opening and closing an analog channel according to a control signal. A first switch unit; And A third diode installed at a second output end of the band pass filter and opening and closing a digital channel according to a control signal, and a fourth diode provided at a second output end of the band pass filter and opening and closing an analog channel according to a control signal. And a second switch unit comprising: a digital / analog broadcast receiver. The method of claim 8, And the path selector is switched in accordance with an externally applied control signal to control whether the operating power is supplied to the gain control amplifier.

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