JP2001044870A - Digital broadcast receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economically configure a digital broadcast receiver having an input circuit for tuners, that can supply a signal incoming from an antenna to respective tuners for analog broadcast reception and digital broadcast reception, without causing the quality of the signal to deteriorate. SOLUTION: In this receiver, a signal incoming from an antenna is supplied to an antenna input terminal 21 of a connector 20 where a shielded balun is built in, an analog tuner is connected to an analog tuner output terminal 21b and a digital tuner is connected to a digital tuner output terminal 21c, while the impedance is matched in a shielded state respectively so that the respective tuners conduct demodulation simultaneously, without being affected by interference noises from the surrounding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna circuit of a broadcast receiving apparatus, and more particularly to a circuit for distributing a signal from an antenna in a shared receiving apparatus for a signal broadcast in an analog system and a signal broadcast in a digital system, and a connector thereof. The present invention relates to a broadcast receiving device including:

[0002]

2. Description of the Related Art Conventionally, television broadcasting according to the NTSC system has been carried out, and a single function device for receiving analog broadcasting has been mainly used as a television receiver. A policy to shift to the digital television system based on OFDM has been issued, preparation for its introduction has progressed, and the start of terrestrial digital broadcasting is approaching. The NTSC system requires a bandwidth of 6 MHz to transmit a one-channel television signal. The terrestrial digital television system using OFDM, which is being considered for introduction, broadcasts a three-channel television program in a 6 MHz band. It will be an important transition in the multimedia era, which is becoming increasingly scarce, as possible.

[0003] In the broadcasting system based on OFDM, an information signal to be transmitted is divided into hundreds to thousands of digital carriers.
This is a modulation method for frequency multiplexing transmission. Carriers constituting OFDM are arranged at equal frequency intervals so as to maintain an orthogonal relationship with each other in order to prevent interference between adjacent carriers. The time given by the reciprocal of the frequency interval is a symbol period, and each carrier is modulated for each symbol period by, for example, well-known QPSK to transmit an information signal. The information signal is, for example, by three streams, for example, Q
Selects the multi-valued number of AM modulation and performs layered modulation, such as broadcasting for mobile reception and broadcasting for fixed reception of high-definition video, and is suitable for the quality of the received signal. It has also been devised so that it can display high quality video. In this way, the television broadcasting system in Japan will shift from the current analog television broadcasting to a new OFDM terrestrial digital television broadcasting, and the appearance of a receiving device corresponding to it is desired.

[0004]

Here, a method for supplying a signal from an antenna to a tuner circuit used in a conventional broadcast receiving apparatus will be described. The tuner circuit supplies a signal received from an antenna in a receiving device such as a television signal, and the receiving device does not illustrate the signal.
For example, it has a function of performing signal processing such as amplification of a weak signal and frequency conversion necessary for supplying a signal to a signal processing circuit that performs demodulation processing and the like.

FIG. 7 shows the structure of a conventional tuner. An analog tuner board 32 is housed in a space electrically shielded from surroundings by a shield case 33, and a signal coming from an antenna is The signal is supplied to the analog tuner board 32 via the antenna connector 34. The analog tuner board 32 also amplifies the signal from the weak antenna with a good S / N ratio and performs processing such as frequency conversion (not shown) if necessary. Is supplied to a subsequent stage, for example, an intermediate frequency amplifying circuit (not shown) via a pin 36.

FIG. 8 is a schematic plan view of a conventional tuner, in which a tuner substrate 32 is installed in a space electrically shielded from the surroundings by a shield case 33, and a signal coming from a weak antenna is not transmitted. Amplification of a high-quality signal supplied via the antenna connector 34, for example, signal processing such as frequency conversion is performed in the same manner as described above.

By the way, as described above, the broadcasting system is the current N
Work is underway to shift from TSC broadcasting to terrestrial digital broadcasting using OFDM, but due to the spread of wireless telephones, the frequency shortage is serious and it is difficult to secure a dedicated frequency band for digital broadcasting. Situation.
Therefore, the introduction of terrestrial digital broadcasting by OFDM is supposed to be performed using the empty channel of the current NTSC broadcasting. For example, during a transition period of about 10 years,
Both analog and digital broadcasting will be performed in the same frequency band. The time when the new digital broadcasting starts may differ depending on the broadcasting company and the location of the broadcasting station. It depends on the difference of replacement time of receiver of the receiver.

[0008] In order to cope with the situation where the switching time is various and the broadcasting system and the receiving device coexist, the viewer must use both the analog system and the digital system during the transition period. Therefore, a device that can receive the data is required, and a dual-purpose receiving device needs to be supplied.

However, the antenna circuit supplied to the place where the viewer installs the receiving device is often one circuit, and the analog / digital dual-purpose receiving device supplies a signal from the antenna to each tuner circuit. It is desirable to do, but the number of antenna circuits arranged at the normal receiving position will be insufficient, and the dual-use receiving device,
It is necessary to provide a broadcast receiving apparatus that supplies a signal from one antenna circuit to a tuner circuit for receiving analog and digital broadcasts while maintaining good signal quality with low loss.

FIG. 9 shows a circuit for supplying a signal from an antenna in the case where, for example, two analog tuners are mounted and a receiving device for receiving two analog broadcast waves at the same time is formed by a conventional technique. The structure is shown and described in a side view. In the figure, a first analog tuner 32 surrounded by a shield case 33 is provided on an analog signal board 31, and a second analog tuner surrounded by a shield case 33b is provided on an analog signal board 31b. 32b is installed. The shield case 33 is provided with an antenna connector 34, and a signal supplied from the antenna is supplied to the first analog tuner board by inserting, for example, an F connector into the antenna connector 34.

To supply a signal coming from the antenna to the second tuner, the signal supplied to the first tuner is supplied to the analog signal board 31 by a pin 36 connecting the tuner and the analog signal board, The signal is guided to the end of the first analog signal board 31 via an exposed circuit section 38 formed in a pattern on the board, and the guided signal is transmitted to the second analog signal board 31b by, for example, a jumper wire 37 of a coaxial cable. To the end, and the signal at that end is
The pin 36 connected to the analog tuner board 32b is supplied by the exposure circuit 38b, and the signal coming from the antenna is supplied to the second analog tuner board 3
2b.

FIG. 10 shows the means used for these connections with the same reference numerals assigned to the same parts as viewed from the back surface of the substrate.

As described above, the signal supplied from the antenna in the receiving apparatus having two tuners according to the conventional example described above is obtained by converting the signal supplied to one tuner using a printed circuit board, a jumper wire or the like, and using the other. It was only enough to supply to the tuner circuit. Therefore, in this case, it is necessary to receive a signal supplied as a weak signal in a good C / N state such that the signal of the antenna supplied to the other tuner circuit is subjected to interference due to induction from an adjacent circuit. Could not.

Therefore, according to the present invention, the signal from the antenna is supplied to the two tuner circuits with a small amount of attenuation by using a connector having a built-in balun for the signal from the antenna in the two tuner circuits, and the signal is provided inside the receiver. For example, by being able to receive signals without being affected by interfering signals emitted from digital circuits or the like, it is possible to receive two channel signals simultaneously, An object of the present invention is to provide an inexpensive receiver having a configuration capable of simultaneously receiving signals and outputting a plurality of demodulated signals. / N in a good state.

[0015]

The present invention comprises the following means to solve the above-mentioned problems. That is,

At least in a broadcast receiving apparatus for receiving a digitally modulated broadcast wave having first and second tuners which are isolated and electrically shielded, a single input signal is converted into two or more signals. And a signal that is electrically shielded and is supplied from the antenna to the subsequent stage.
And a signal supply means for converting the impedance of the single input signal in accordance with the input impedance of the first tuner, and dividing the single input signal into two or more signals. Balun, electrically shielded,
A second signal supply unit for supplying one of the signals obtained by dividing the balun to the first tuner circuit; And a third signal supply means for supplying one of the signals to the second tuner circuit. The first and second tuners output a predetermined channel signal from the signals obtained by the division. Characterized in that they are demodulated and output simultaneously.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a digital broadcast receiving apparatus equipped with a balun built-in connector according to the present invention and capable of receiving signals of a plurality of channels simultaneously will be described below.

FIG. 1 is a schematic plan view, partially in section, of a high-frequency circuit section of a digital broadcast receiving apparatus equipped with a balun built-in connector according to the embodiment and receiving analog and digital television broadcasts one channel at a time. And will be described. In the figure, demodulation of analog broadcasting by NTSC is performed by an analog signal board 31 and an analog tuner board 32 standing on the board.
Further, reception of a digital broadcast broadcast by OFDM is performed by a digital signal board 41 and a digital tuner board 42 standing on the board.

The signals input from the antenna to the analog tuner board 32 and the digital tuner board 42 are supplied using the balun built-in connector 20 which divides a single input signal into two signals and outputs the two signals. , And divides the signal coming from the antenna to each tuner circuit and supplies it. The balun built-in connector 20 shown in this example includes an antenna input terminal 21a and an analog tuner output terminal 21.
b, a digital tuner output terminal 21c, and the input terminal 21a, the output terminals 21b and 21c are of an integrated structure shielded by a metal sheath, and a signal coming from the antenna to the antenna input terminal 21a is received. The signals supplied to the analog tuner output terminal 21b and the digital tuner output terminal 21c are supplied to the analog tuner board 32 and the digital tuner board 42, respectively.

When the signal impedances of the output terminals 21b and 21c have the same value as the impedances of the antenna input terminals of the analog tuner board 32 and the digital tuner board 42, the signal impedance is maintained in the input / output circuit. The impedance of the signal output from the balun is set so as to be the same as the input impedance of each of the tuner boards 32 and 42, and the signal input from the antenna is divided and supplied.

As described above, the balun built-in connector shown in this embodiment performs a shielding process for preventing noise from being mixed into an incoming signal from a particularly weak antenna, as well as an antenna circuit and an input circuit of each tuner. Even for weak signals supplied from the antenna, such as taking impedance matching, prevent interference noise from other peripheral circuits from being mixed in, and supply signals of appropriate levels to those tuner circuits. , Each tuner circuit 32,
Reference numeral 42 is configured to obtain a demodulated signal having a small noise level.

FIG. 2 shows an external view of a tuner for a digital receiving apparatus equipped with a balun built-in connector. In the figure, a balun built-in connector 20 is attached to a shield case 43 that houses a digital tuner board 42.

FIG. 3 is a schematic cross-sectional view showing the inside of the balun built-in connector. The balun built-in connector 20 has an antenna input terminal 21a and an analog tuner output terminal 21.
b, digital tuner output terminal 21c, lead wire 2
2a to 22c, a balun 23, and a board 24 for fixing the balun to the connector. The base 24 is formed of a conductive material such as metal and has a shielding effect. There is a stand 24 on which the balun is placed.

The balun 23 shown in this example is a high-frequency transformer in which a coil is wound around a cylindrical magnetic core, and coils corresponding to one input circuit and two output circuits are wound, and one input circuit is wound around the input circuit. Is connected to the antenna input terminal 21a by a lead line 22a, and the two output circuits are connected to the analog tuner output terminal 21b and the digital tuner output terminal 21c by two lead lines 22b and 22c, respectively. I have.

A signal input from an antenna is supplied to an input terminal 21a, and an antenna input circuit of an analog tuner is provided to two output terminals 21b and 21c, respectively.
The antenna input circuit of the digital tuner is connected.
These input terminals 21 in the balun built-in connector 20
a, and the impedances of the two output terminals 21b and 21c are all 75 ohms, and the impedance of the input circuit is the same as the impedance of the coaxial cable connected to the antenna. Is also set to 75 ohms.

Here, if the input terminals of the analog tuner and the digital tuner are connected in parallel and a connection is made to supply a signal from the antenna to the connection point, the impedance of the connection point is 1 of 75 ohms. When the signal from the antenna of 75 ohm is supplied thereto, a loss due to impedance mismatch occurs. However, if the impedance is matched using balun as in the present embodiment, the coupling is performed. The loss can be reduced, the signal coming from the antenna can be efficiently supplied to the two tuners, and the operation can be performed so that a good demodulated signal can be obtained.

FIG. 4 is an exploded perspective view showing an example of connection between an analog tuner and a digital tuner using the balun built-in connector connected in this manner, and will be described. In the figure, a balun built-in connector 20 is attached to a shield case 43 that houses a digital tuner board 42, and an analog tuner output terminal 21 b of the balun built-in connector 20 has a shield case 33 that houses the analog tuner board 32. The state where the antenna connector 34 is inserted and connected is indicated by an arrow.

The analog tuner 30 shown here uses a stable mass-produced tuner used for a conventional NTSC analog television signal receiver as it is. In the conventional receiver, a signal supplied from an antenna is not used. ,
Although supplied directly to the antenna connector 34 by, for example, an F-type connector, the antenna connector 34 is used as it is without changing the analog tuner.

FIG. 5 is a side view showing how these digital tuners and analog tuners are connected.
In the figure, a shield case 43 for standing and storing a digital tuner board 42 on a digital signal board 41
6 and the like, and the balun built-in connector 20 is attached to the shield case 43. Analog tuner output terminal 21b of the built-in balun connector
Has an antenna connector 34 inserted therein, and supplies a signal coming from the antenna to the analog tuner board 32 housed in the shield case 33 via these connections.

FIG. 6 is a schematic plan view showing the above connection. The digital tuner board 42 and the analog tuner board 3 for the balun built-in connector 20 in FIG.
Connection to connector 2 is as described above.
For example, a signal supplied from an antenna is connected to the antenna input terminal 21a of the “0” via an F connector or the like, and a signal from the balun is output to an analog tuner output terminal 21b.
The signals are supplied to the tuners via the digital tuner output terminal 21c.

The supplied signals are supplied to connector 2
The impedance is matched by the balun transformer provided in the space shielded by the outer skin of 0, and it is made to be supplied to each tuner with low loss.
Since all the circuits arranged for this purpose are performed in a shielded space, the signal from the analog signal board 31, the digital signal board 41, and other signal boards (not shown) can be used even for a signal from an incoming weak antenna. Each of the tuners performs processing such as amplification and frequency conversion of an incoming signal while minimizing received interference.

As described above, according to the apparatus of the present embodiment, the weak signal coming from the antenna is not
0, the analog tuner board 32 shielded by the shield case 33 and the shield case 4
Digital tuner board 42 shielded by 3
Is supplied as a signal having an appropriate impedance while being shielded, so that interference signals generated by various electronic circuits in the receiver are not disturbed and the S / N of the carrier is not deteriorated. In particular, digital signal receiving devices can amplify weak signals without being affected by unnecessary interference signals generated by many digital circuits. It has the effect of obtaining a small number of demodulated signals, especially when receiving high-definition video information by QAM modulation with a large number of multivalues to be broadcast in the future, such as in a fringe area where high-definition video information service is provided. It is necessary to perform demodulation with an increased S / N of the digital broadcast receiver, and the digital broadcast receiving apparatus using this configuration can secure a high reception S / N. Including reception of high definition video information signal, there are effects such as making it possible to receive stably broadcast of interest.

In the above embodiment, the supply of the signal from the antenna to the analog tuner and the digital tuner is described. However, the present invention is not limited to this, and the signal from the antenna is supplied to the digital tuner and other digital tuners. Has the same effect.

Further, in the above embodiment, an example is shown in which a signal coming from the antenna is supplied to the two tuners, but a digital tuner board is provided on the opposite side of the analog tuner board 32 shown in FIG. It is also possible to apply the present invention to a receiving apparatus that uses three or more digital tuners to obtain digital demodulated signals of multiple channels.

In the case of a receiving apparatus capable of simultaneously obtaining digital demodulated signals of a plurality of channels, for example, it is connected to a home server capable of recording programs of a plurality of channels at the same time and supplies a plurality of demodulated signals at the same time. Records can be made.

As an application of a receiving apparatus capable of simultaneously obtaining digital demodulated signals of a plurality of channels, there is a usage method in which a program is viewed while instantaneously switching a plurality of receiving channels. That is, the operation from when the channel is switched by the OFDM digital receiver to when the demodulated video signal is obtained is, for example, OFD
A synchronization pull-in time for generating a synchronization signal for receiving an M signal, a time for deinterleaving such as changing the order of a demodulated OFDM signal, and decoding of a video signal by decoding data encoded by the MPEG method. Have a long time to get. Recently, as a method of viewing television, a method of frequently switching channels to enjoy many programs at the same time has been used. Can be instantaneously switched for viewing.

[0037]

According to the present invention, even for a weak signal supplied from an antenna, two or more signals with impedance matching can be obtained by using a balun installed in a space shielded from the surroundings. However, since the signals are supplied to the respective tuner circuits, there is an effect that it is possible to configure a digital broadcast receiving apparatus that obtains an output obtained by simultaneously demodulating the signals supplied to the tuners while minimizing the deterioration of the C / N.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional plan view illustrating a digital broadcast receiving device equipped with a balun built-in connector of the present invention.

FIG. 2 is an external view of a tuner for a digital broadcast receiving apparatus equipped with a balun built-in connector of the present invention.

FIG. 3 is a schematic cross-sectional view showing the inside of the balun built-in connector of the present invention.

FIG. 4 is an exploded perspective view illustrating the connection of two tuners on which the balun built-in connector of the present invention is mounted.

FIG. 5 is a schematic side view in which two tuners are connected by a balun built-in connector of the present invention.

FIG. 6 is a schematic plan view in which two tuners are connected by a balun built-in connector of the present invention.

FIG. 7 is a diagram illustrating the structure of a conventional tuner.

FIG. 8 is a schematic plan view of a conventional tuner.

FIG. 9 is a side view illustrating the structure of a receiving device in which two conventional tuners are mounted.

FIG. 10 is a diagram illustrating connection of an antenna circuit on which two conventional tuners are mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Digital receiver 20 Balun built-in connector 21a Antenna input terminal 21b Analog tuner output terminal 21c Digital tuner output terminal 22a-22c Leader line 23 Balun 24 Board 30 Analog tuner 31, 31b Analog signal board 32, 32b Analog tuner board 33, 33b Shield case 34 Antenna connector 35 Antenna terminal 36 pin 37 Jumper wire 38, 38b Exposed circuit part 41 Digital signal board 42 Digital tuner board 43 Shield case 44 Antenna terminal 46 pin

Claims (1)

[Claims] 1. A broadcast receiving apparatus for receiving a digitally modulated broadcast wave having at least first and second tuners which are isolated and electrically shielded, respectively, wherein two or more single input signals are received. A first signal supply means for dividing the signal into a plurality of signals and electrically supplying a signal coming from the antenna to the subsequent stage, and providing the signal on the latter stage and shielding the single input signal. A balun for transforming the impedance in accordance with the input impedance of the first tuner and dividing it into two or more signals, and one of the signals that are electrically shielded and obtained by dividing the balun, Second signal supply means for supplying to the first tuner circuit; and another signal which is electrically shielded and obtained by dividing from the balun, for supplying another signal to the second tuner circuit. The third Digital broadcasting, comprising: a signal supply unit; wherein the first and second tuners are configured to demodulate predetermined channel signals from signals obtained by dividing the respective signals and to output the signals simultaneously. Receiver.