KR100755647B1 - Digital terrestrial tuner with variable if bandwidth - Google Patents

Abstract

According to the present invention, a variable IF that can cover three different IF passbands with a single SAW filter can be implemented in a digital terrestrial receiver by implementing a passband of an SAW filter for IF bandpass among 6 MHz, 7 MHz, and 8 MHz. Its purpose is to provide a digital terrestrial receiver with a bandwidth.

Digital terrestrial receiver having a variable IF bandwidth of the present invention, RF unit 100 for converting the RF signal corresponding to the selected channel (SCS) of the received RF signal into an IF signal; A band selector 200 for selecting one of a plurality of IF passband selecting terminals according to a broadcast selection (SBS); A variable band SAW filter (300) for passing an IF signal from the RF unit (100) to an IF pass band determined according to terminal selection by the band selector (200); And an IF unit 400 for amplifying and filtering the IF signal from the variable band SAW filter 300.

Digital, terrestrial, tuner, IF, bandwidth, variable

Description

Digital Terrestrial Receiver with Variable IF Bandwidth {DIGITAL TERRESTRIAL TUNER WITH VARIABLE IF BANDWIDTH}

1 is a block diagram of a conventional digital terrestrial receiver.

2 is a block diagram of a digital terrestrial receiver in accordance with the present invention.

3 is a detailed circuit diagram of a SAW filter and a band selector of FIG. 2.

4 is a variable IF bandwidth graph according to the present invention.

Explanation of symbols on the main parts of the drawings

100: RF unit 200: band selection unit

300: variable band SAW filter 400: IF unit

310: filter circuit SCS: selection channel

SBS: Broadcast selection N1: 1st connection node

N2: second connection node N3: third connection node

T1: terminal for selecting the first passband T2: terminal for selecting the second passband

T3: Terminal for selecting the third pass band

The present invention relates to a digital terrestrial receiver applied to a TV set or a set-top box, and more particularly, in a digital terrestrial receiver, by implementing a passband of the SAW filter for IF band pass among one of 6 MHz, 7 MHz, and 8 MHz, The present invention relates to a digital terrestrial receiver having a variable IF bandwidth capable of covering one IF passband with one SAW filter.

In general, VHF using 7MHz bandwidth and UHF using 8MHz bandwidth have been used for analog terrestrial broadcasting, and DVB-T broadcasting of digital terrestrial broadcasting uses 6MHz bandwidth. Recently, in the case of implementing each broadcast to be received by one receiver, interest has been increased in producing a compact and unity in order to reduce the production cost.

1 is a block diagram of a conventional digital terrestrial receiver.

The conventional digital terrestrial receiver shown in FIG. 1 includes an RF unit 11 for converting an RF signal corresponding to channel selection among RF signals from an antenna ANT into an IF signal, and an IF signal from the RF unit 11. A SAW filter 12 passing through a predetermined IF band and an IF unit 13 for amplifying and filtering the IF signal from the SAW filter 12 and outputting the demodulation unit.

When the digital terrestrial receiver is implemented for each broadcasting scheme, the SAW filter is implemented as a filter fixed to a corresponding bandwidth. That is, the SAW filter 12 is set to a bandwidth of 7MHz when applied to a VHF terrestrial TV tuner, and is set to a bandwidth of 8MHz when applied to a UHF terrestrial TV tuner, and is applied to a DVB-T tuner that is a digital terrestrial broadcaster. If applicable, it is set to a bandwidth of 6MHz.

In the conventional digital terrestrial receiver, the UHF scheme with a bandwidth of 8 MHz is adopted. For this purpose, the SAW filter 12 is implemented as a filter passing 8 MHz.

Recently, the 7 MHz VHF scheme has coexisted with the 8 MHz UHF scheme described above, and the 6 MHz DVB-T broadcasting scheme has joined together, and now, in one digital terrestrial receiver, to receive broadcasts having different bandwidths, respectively. It should include a SAW filter that passes IF bandwidths of 6MHz, 7MHz, and 8MHz.

Research and development of such a SAW filter are underway at various angles.

The most widely used method includes a plurality of SAW filters for each broadcast, that is, 6 MHz, 7 MHz, and 8 MHz, and also selects a corresponding SAW filter through a separate switching element.

However, such a conventional digital terrestrial receiver has a SAW filter corresponding to each broadcasting system separately, so that the circuit of the tuner becomes complicated, thereby increasing the production cost of the tuner.

The present invention has been proposed to solve the above problems, and the object of the present invention is to implement the three different from each other by implementing a passband of the SAW filter for the IF band pass, one of 6MHz, 7MHz and 8MHz in the digital terrestrial receiver The present invention provides a digital terrestrial receiver having a variable IF bandwidth that can cover an IF passband with a single SAW filter.

In order to achieve the above object of the present invention, a digital terrestrial receiver having a variable IF bandwidth of the present invention, the RF unit for converting an RF signal corresponding to the selected channel of the received RF signal into an IF signal; A band selector for selecting one of a plurality of IF passband selecting terminals according to a broadcast selection; A variable band SAW filter for passing an IF signal from the RF unit to an IF pass band determined according to terminal selection by the band selector; And an IF unit for amplifying and filtering the IF signal from the variable band SAW filter.

The variable band SAW filter includes: a filter circuit including a plurality of inductance elements and capacitance elements; A first passband selection terminal connected to the first connection node of the filter circuit; A second passband selection terminal connected to a second connection node of the filter circuit; And a third pass band selection terminal connected to the third connection node of the filter circuit.

The variable band SAW filter may be configured such that the first, second, and third pass bands correspond to 6 MHz, 7 MHz, and 8 MHz pass bands.

The band selector is configured to connect one of the terminals for selecting the first, second and third passbands to ground according to the broadcast selection.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings referred to in the present invention, components having substantially the same configuration and function will use the same reference numerals.

2 is a block diagram of a digital terrestrial receiver according to the present invention.

Referring to FIG. 2, the digital terrestrial receiver according to the present invention includes an RF unit 100, a band selector 200, a variable band SAW filter 300, and an IF unit 400.

The RF unit 100 converts an RF signal corresponding to a selected channel (SCS) among the received RF signals into an IF signal and outputs the IF signal to the variable band SAW filter 300.

The band selector 200 selects one of a plurality of IF passband selection terminals of the variable band SAW filter 300 according to broadcast selection (SBS).

The variable band SAW filter 300 passes the IF signal from the RF unit 100 through the IF passband determined according to the terminal selection by the band selector 200 and outputs the IF signal to the IF unit 400. .

The IF unit 400 amplifies, filters, and outputs the IF signal from the variable band SAW filter 300.

In this case, the RF unit 100 includes: an RF circuit for amplifying and filtering an input RF signal, an oscillator for generating an oscillation frequency corresponding to the selected channel (SCS), a signal from the RF circuit, and the oscillator from the It includes a mixer for mixing the oscillation frequency of the output IF signal.

3 is a detailed circuit diagram of the SAW filter and the band selector of FIG. 2.

Referring to FIG. 3, the variable band SAW filter 300 may include a filter circuit 310 including a plurality of inductance elements and capacitance elements, and a first connection node N1 connected to the first connection node N1 of the filter circuit 310. A first passband selecting terminal T1, a second passband selecting terminal T2 connected to the second connecting node N2 of the filter circuit 310, and a third connecting node of the filter circuit 310. And a third passband selecting terminal T3 connected to N3.

Here, the filter circuit 310 is formed of different filtering circuits as the connection nodes N1, N2, and N3 are grounded. For example, when the first connection node N1 is grounded, the passband filter is 6 MHz. When the second connection node N2 is grounded, the passband filter is 7 MHz. When the three connection node N3 is grounded, the connection node N3 may include a passband filter of 8 MHz.

The variable band SAW filter 300 is configured such that the first, second and third pass bands correspond to 6 MHz, 7 MHz and 8 MHz pass bands.

The band selector 200 is configured to connect one of the first, second, and third passband selecting terminals T1, T2, and T3 to ground according to the broadcast selection SBS.

4 is a variable IF bandwidth graph according to the present invention.

In FIG. 4, it can be seen that the IF bandwidth according to the present invention is changed to the first, second and third pass bands BW1, BW2, and BW3. Here, the first, second and third passbands BW1, BW2, and BW3 correspond to 6MHz, 7MHz, and 8MHz passbands.

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

Referring to FIG. 2, in the digital terrestrial receiver according to the present invention, the RF unit 100 converts an RF signal corresponding to a selection channel (SCS) among the received RF signals into an IF signal.

In more detail, the RF circuit of the RF unit 100 amplifies and filters the input RF signal and outputs the result to the mixer, and the oscillator generates the oscillation frequency corresponding to the selected channel SCS by the mixer. Will output

At this time, the mixer outputs an IF signal by mixing the signal from the RF circuit and the oscillation frequency from the oscillator.

Next, the band selector 200 of the present invention selects one of a plurality of IF passband selecting terminals of the variable band SAW filter 300 of the present invention according to broadcast selection (SBS). Accordingly, the variable band SAW filter 300 of the present invention transfers the IF signal from the RF unit 100 to the IF unit 400 in the IF passband determined according to the terminal selection by the band selector 200. Pass it through.

For example, when the first connection node N1 is grounded by the band selector 200, the variable band SAW filter 300 operates as a 6 MHz passband filter and the band selector 200. In case that the second connection node N2 is grounded, the variable band SAW filter 300 operates as a passband filter of 7 MHz, and the third connection node N3 is operated by the band selector 200. In case of grounding), the variable band SAW filter 300 may operate as a passband filter of 8 MHz.

Next, the IF unit 400 amplifies and filters the IF signal from the variable band SAW filter 300 and outputs the demodulation unit.

Referring to FIG. 3, the variable band SAW filter 300 includes a filter circuit 310 including a plurality of inductance elements and capacitance elements, and first, first, and first filters of the filter circuit 310. First, second and third passband selecting terminals T1, T2, and T3 connected to third connection nodes N1, N2, and N3, wherein the first, second, and third passbands are 6 MHz. The case corresponding to the 7 MHz and 8 MHz passbands will be described.

In this case, the band selector 200 selects one of the first, second, and third passband selecting terminals T1, T2, and T3 according to the broadcast selection (SBS). One of the 1,2 and 3 terminals respectively connected to the terminals T1, T2, and T3 is connected to the ground G.

As described above, the present invention enables the SAW filter to be variable to IF passbands of 6 MHz, 7 MHz, and 8 MHz so as to correspond to each broadcasting scheme, so that each broadcast can be selectively received by one receiver. .

Accordingly, a signal input to four terminals of the variable band SAW filter 300 is passed through the set IF band and output through five terminals.

On the other hand, referring to Figure 4, it can be seen that the IF bandwidth according to the present invention can be changed to 6MHz, 7MHz and 8MHz passbands of the first, second and third passbands (BW1, BW2, BW3).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, but is defined by the claims, and the apparatus of the present invention may be substituted, modified, and modified in various ways without departing from the spirit of the present invention. It is apparent to those skilled in the art that modifications are possible.

According to the present invention as described above, in the digital terrestrial receiver applied to a receiver such as a TV set or a set-top box, by implementing so that the passband of the SAW filter for IF band pass can be selected from one of 6MHz, 7MHz and 8MHz, Since three IF passbands can be covered by one SAW filter, and the bandwidth can be varied by one SAW filter, a separate SAW filter is not necessary, and thus manufacturing cost can be reduced.

Claims (4)

An RF unit for converting an RF signal corresponding to a selected channel among the received RF signals into an IF signal; A band selector for selecting one of a plurality of IF passband selecting terminals according to a broadcast selection; A variable band SAW filter for passing an IF signal from the RF unit to an IF pass band determined according to terminal selection by the band selector; And An IF unit for amplifying and filtering the IF signal from the variable band SAW filter, The variable band SAW filter includes: a filter circuit including a plurality of inductance elements and capacitance elements; A first passband selection terminal connected to the first connection node of the filter circuit; A second passband selection terminal connected to a second connection node of the filter circuit; And a third passband selecting terminal connected to the third connection node of the filter circuit. Digital terrestrial receiver having a variable IF bandwidth, characterized in that. delete The method of claim 1, wherein the variable band SAW filter, And the first, second and third passbands correspond to 6MHz, 7MHz and 8MHz passbands. The method of claim 1 or 3, wherein the band selector, And terminating one of the first, second and third passband selection terminals to ground according to the broadcast selection.

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