KR20100129911A - Analog/digital broadcasting receiving apparatus - Google Patents

Abstract

PURPOSE: An analog/digital broadcasting receiving apparatus is provided to turn on a corresponding IF line by separating an analog IF line from a digital IF line at a rear portion of an MOPLL unit when selecting an analog broadcasting or digital broadcasting. CONSTITUTION: An MOPLL(Mixer Oscillator Phase Locked Loop) unit(110) converts an RF signal of a desirable channel into an IF(Intermediate Frequency) signal. A path selection unit(130) selectively outputs the IF signal through a digital channel or analog channel. An analog filter unit(150) blocks the IF signal of a preset specific frequency band in the IF signal. A demodulator(170) demodulates the digital IF signal of the path selection unit and the analog IF signal of the analog filter unit.

Description

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

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

Recently, the digitization 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 when the digitalization of television broadcasting proceeds, the existing analog broadcasting is not immediately stopped. Therefore, in the transition period from analog broadcasting to digital broadcasting, analog broadcasting and digital broadcasting coexist.

For this reason, broadcast receivers capable of receiving both analog and digital broadcasts are now widespread.

In the case of the analog / digital combined television, an analog / digital common tuner is generally used, and a demodulation IC for demodulating analog and digital broadcast signals is located at the rear of the tuner.

In the case of the demodulation IC, the analog demodulation unit and the digital demodulation unit are separately used for multifunctionalization, but in the case of the new IC, analog and digital broadcasting can be demodulated with one demodulation IC.

However, by using a single demodulation IC, it is possible to reduce the size of the receiver and to secure a competitive price. However, when both analog and digital broadcast signals are demodulated, loss of each other occurs (Trade off). Was done.

For example, when developing an IC mainly for analog function, a problem may occur in digital signal processing, and when developing an IC for digital function forgery, a problem may occur in analog signal processing.

The present invention provides an analog / digital broadcast receiver capable of securing the best performance by preventing mutual loss due to trade off of analog and digital performance during analog and digital signal processing in a combined analog / digital receiver. It is to.

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, an analog / digital broadcast receiver according to the present invention receives a digital broadcast signal and an analog broadcast signal, selects an RF signal of a specific channel among the received RF broadcast signals, converts the IF signal, and outputs the IF signal. MOPLL portion; A path selector for selectively outputting an IF signal input from the MOPLL unit to a digital channel or an analog channel according to a control signal; An analog filter unit installed on the analog channel to block and output an IF signal of a predetermined frequency band among IF signals input from the path selector; And a demodulator configured to demodulate the digital IF signal input from the path selector and the analog IF signal input from the analog filter.

In detail, the path selector may include: a first switch unit disposed between the output terminal of the MOPLL unit and the analog filter unit to open and close an analog channel according to a control signal; And a second switch unit disposed between the output terminal of the MOPLL unit and the demodulator and opening and closing the digital channel according to a control signal.

As described above, the present invention is configured by separating analog and digital IF lines at the rear end of the MOPLL unit, and turning on the corresponding IF line at the time of analog broadcasting or digital broadcasting tuning, so that both analog and digital broadcasting signals can be best processed. There is an advantage to that.

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 view showing an analog / digital combined receiver according to the present invention. The receiver 1 includes a MOPLL unit 10, a filter unit 20, and a demodulator 30.

The MOPLL unit 10 (mixer oscillator phase locked loop) includes a mixer, a VCO, a PLL, etc., and selects an RF signal of a specific channel selected by a user from among input RF broadcast signals and converts the selected RF signal into an intermediate frequency band. The analog / digital converter converts and outputs a signal (IF signal).

The filter unit 20 is composed of an LC parallel resonant circuit that blocks and outputs a specific frequency band of an analog or digital IF signal output from the MOPLL unit 10. The LC parallel resonant circuit may be installed as a multi-stage trap (21, 22), and operates as a band stop filter.

The demodulator 30 is analog / digital common for demodulating analog or digital IF signals input through the filter unit 20 and outputting video and audio signals.

The receiving device 1 configured as shown in FIG. 1 transmits the IF signal to the demodulator 30 through the same IF transmission line regardless of the time of analog broadcast and digital broadcast tuning.

Since the analog IF signal and the digital IF signal have characteristics such as frequency bands, problems may occur in signal processing in a demodulation unit at a later stage when the same transmission circuit is used.

2 is a block diagram illustrating an analog / digital receiving device according to the present invention. The receiving device 100 includes a MOPLL unit 110, a path selector 130, an analog filter unit 150, and a demodulator 170. It is configured to include.

The MOPLL unit 110 includes a local oscillator 111 and a mixer 115. The MOPLL unit 110 receives a digital broadcast signal and an analog broadcast signal, but inputs a specific channel of a desired RF broadcast signal. It is analog / digital common for selecting RF signal and converting it into intermediate frequency signal (IF signal).

The local oscillator 111 generates a local signal LO1 for channel tuning for the selected channel under the control of a controller (not shown). The local oscillator 111 may include a Voltage Controlled Oscillator (VCO) and a Frequency-Phase Locked Loop (FPLL), and the local signal has a variable frequency according to a channel selected by a user.

The mixer 115 synthesizes the input RF signal and the local signal for the selected channel input from the local oscillator 111 and down-converts the IF signal to the required IF signal. The mixer 115 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 MOPLL unit 110 may further include an AGC (Automatic Gain Control) amplifier for automatically controlling the gain of the IF signal output from the mixer 115 according to the control signal.

The path selector 130 variably controls the transmission line of the IF signal output from the MOPLL unit 110 according to a control signal (Control) input from the outside, and the IF signal according to the control signal analog channel (A_IF) Alternatively, the digital channel D_IF may be selectively opened and closed. The control signal may be input from a controller (not shown) or a demodulator 170.

The analog filter unit 150 is installed on an analog channel to block and output an IF signal of a predetermined frequency band among IF signals input from the path selector 130. The analog filter unit 150 may be any one of a SAW filter, LC filter, ceramic filter, or analog IC filter.

The demodulator 170 demodulates the digital IF signal input from the path selector 130 or the analog IF signal input from the analog filter unit 150 to output video and audio signals.

As described above, the present invention is configured by separating the analog and digital IF lines through the path selection unit 130 at the rear end of the MOPLL unit 110, and turning on the corresponding IF line when the analog broadcasting or digital broadcasting is tuned, and the analog and digital All broadcast signals can be best processed.

3 is a circuit diagram illustrating a detailed configuration of the path selector and the analog filter of FIG. 2 according to an embodiment of the present invention.

The path selector 130 includes a first switch unit 131 and a second switch unit 135. The first switch unit 131 and the second switch unit 135 include a switching diode. It is composed.

The first switch unit 131 includes a first diode D1 disposed between the output terminal of the MOPLL unit 110 and the analog filter unit 150 to open and close the analog channel A_IF according to a control signal. That is, the first switch unit 131 controls the first capacitor C1 provided between the output terminal of the MOPLL unit 110 and the first node Nd1 and the first node Nd1 as a common node. The control signal Control is provided in the forward direction between the voltage divider R1 and R2 connected between the input terminal and the low potential and the input terminal of the first node Nd1 and the analog filter unit 150 and applied to the first node Nd1. ) Is configured to include a first diode (D1) for opening and closing the analog channel.

The second switch unit 135 includes a second diode D2 disposed between the output terminal of the MOPLL unit 110 and the demodulator 170 and opening / closing the digital channel D_IF according to a control signal. That is, the second switch unit 135 is a control signal using the second capacitor C2 provided between the output terminal of the MOPLL unit 110 and the second node Nd2 and the second node Nd2 as a common node. The control signal Control is installed in the forward direction between the voltage divider R3 and R4 connected between the input terminal and the low potential and the input terminal of the second node Nd2 and the demodulator 170 and applied to the second node Nd2. In accordance with the configuration is configured to include a second diode (D2) for opening and closing the digital channel.

The analog channel is turned on when the control signal applied to the first node Nd1 is high potential, and the digital channel is turned on when the control signal applied to the second node Nd2 is high potential. The control signals applied to the first node Nd1 and the second node Nd2 have different voltage levels. When one channel is turned on, the other channel is turned off.

In FIG. 3, the first switch unit 131 and the second switch unit 135 are described as operating by receiving different control signals, but the first switch unit 131 and the second switch unit 135 have the same control. The switch may be configured to receive a signal, but to receive one of the inverted control signals through an inverter.

The analog filter unit 150 is installed on an analog channel A_IF to cut and output an IF signal of a predetermined frequency band among IF signals input from the path selector 130, and is formed using an LC parallel resonant circuit ( C11 / L11, C12 / L12). The LC parallel resonant circuit is a band stop filter installed as a multi-stage trap (151, 152; trap), the LC parallel resonant circuit of each trap (151, 152) can block signals of different frequency bands Can be.

Therefore, in the present invention, the first switch unit 131 or the second switch unit 135 of the path selector 130 transmits a control signal for selecting the corresponding IF transmission line according to the broadcast tuned at the time of analog broadcast or digital broadcast tuning. ) To selectively turn on an analog channel or a digital channel. Accordingly, as the analog and digital IF signals are supplied to the demodulator 170 through the optimal transmission line and the circuit, both the analog and digital IF signals can be best processed.

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 view showing an analog / digital combined receiver according to the present invention.

2 is a block diagram showing an analog / digital combined receiver according to the present invention.

3 is a circuit diagram illustrating a detailed configuration of the path selector and the analog filter of FIG. 2 according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

100: receiver 110: MOPLL unit

130: path selection unit 131: first switch unit

135: second switch unit 150: analog filter unit

170: demodulator

Claims (7)

A MOPLL unit for receiving a digital broadcast signal and an analog broadcast signal, selecting an RF signal of a desired specific channel among the received RF broadcast signals, and converting the signal into an IF signal; A path selector for selectively outputting an IF signal input from the MOPLL unit to a digital channel or an analog channel according to a control signal; An analog filter unit installed on the analog channel to block and output an IF signal of a predetermined frequency band among IF signals input from the path selector; And And a demodulator for demodulating the digital IF signal input from the path selector and the analog IF signal input from the analog filter. The method of claim 1, The path selector comprises a switch unit for opening and closing a digital channel or an analog channel according to a control signal. The method of claim 1, The path selector includes: a first switch unit disposed between the output terminal of the MOPLL unit and the analog filter unit, and configured to open and close an analog channel according to a control signal; And a second switch unit disposed between an output terminal of the MOPLL unit and a demodulator and configured to open and close a digital channel according to a control signal. The method of claim 3, wherein And the first switch unit and the second switch unit include switching diodes, respectively. The method of claim 3, wherein The first switch unit includes a first capacitor installed between the output terminal of the MOPLL unit and the first node; A voltage divider connected between the control signal input terminal and the low potential using the first node as a common node; And a first diode disposed in a forward direction between the first node and an input terminal of the analog filter unit and opening and closing an analog channel according to a control voltage applied to the first node. The method of claim 3, wherein The second switch unit may include a second capacitor installed between the output terminal of the MOPLL unit and a second node; A voltage divider connected between the control signal input terminal and the low potential using the second node as a common node; And a second diode installed in the forward direction between the second node and the input terminal of the demodulator and opening and closing the digital channel according to a control voltage applied to the second node. The method of claim 1, The analog filter unit comprises a multi-stage LC parallel resonant circuit.

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