JPH11261911A - Digital satellite broadcast reception tuner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tuner that is capable of viewing BS/CS broadcast signals and to make the size of the tuner small by reducing the number of components. SOLUTION: The digital satellite broadcast reception tuner is provided with a tuner front end section 3 that selects a BS/CS high frequency signal of a digital satellite broadcast and applies I/Q demodulation to the signal, a BS digital demodulation section 5 that demodulates an I/Q signal of the BS high frequency signal outputted from the tuner front end section 3, and with a CS digital demodulation section 6 that demodulates an I/Q signal of the CS high frequency signal outputted from the tuner front end section 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital satellite broadcast receiving tuner for receiving two types of digital satellite broadcasts such as BS digital broadcasts and CS digital broadcasts.

[0002]

2. Description of the Related Art A conventional satellite receiving tuner, as described in, for example, Japanese Patent Application Laid-Open No. 6-105252, receives two types of analog satellite broadcasts, a BS analog broadcast and a CS analog broadcast, as shown in FIG. As shown in the figure, two satellite broadcast receiving tuners, a BS analog satellite broadcast receiving tuner 70 and a CS analog satellite broadcast receiving tuner 71, are provided, and the tuners 70, 71 perform demodulation processing to output video / audio signals. .

[0003] A BS analog satellite broadcast receiving tuner 70 has an input terminal 72 for inputting a high frequency signal (RF signal) of the BS analog broadcast, a tuner front end section 73 for performing channel selection and I / Q demodulation from the high frequency signal, and a tuner. A BS analog demodulation unit 74 for demodulating the I / Q signal output from the front end unit 73. Then, the BS analog satellite broadcast receiving tuner 70 transmits 1-byte parallel data D0 to D7 as video and audio signals,
A signal STR_OUT indicating the beginning of a data packet;
A clock BYTE_CLK of data D0 to D7 is output.

Similarly, a CS analog satellite broadcast receiving tuner 71 has an input terminal 75 for inputting a high-frequency signal (RF signal) of CS analog broadcasting, and a tuner front-end section 76 for selecting a channel and performing I / Q demodulation from the high-frequency signal. And I / Q output from the tuner front end unit 76
And a CS analog demodulation unit 77 that performs signal processing on the signal. Then, the CS analog satellite broadcast receiving tuner 71 outputs a video / audio signal having the same configuration as described above. The controller 80 controls the BS analog satellite broadcast receiving tuner 70 and the CS analog broadcast receiving tuner 71 according to the high-frequency signal to be signal-processed.

[0005]

Therefore, conventionally, when two kinds of analog satellite broadcasts are received, two satellite broadcast receiving tuners are required, so that the number of parts is increased and a large space is required. I was

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an analog satellite receiving tuner in which the number of parts is reduced and the size is reduced.

[0007]

According to a first aspect of the present invention, there is provided a tuner front end unit for selecting a high frequency signal of a received satellite broadcast and performing I / Q demodulation, Performing a first demodulation process on an I / Q signal output from the tuner front end unit;
, And a second digital demodulation unit for performing a second demodulation process on the I / Q signal.

According to such a configuration, the digital satellite broadcast receiving tuner performs channel selection and I / Q demodulation in the tuner front end unit, for example, when receiving high-frequency signals of BS digital broadcast and CS digital broadcast. . The I / Q signal output from the tuner front-end unit is subjected to signal processing by the BS digital demodulation unit and the CS digital demodulation unit. Then, the video signal is reproduced by an MPEG demodulation circuit or the like provided at the subsequent stage of the digital satellite broadcast receiving tuner.

Further, in the second configuration of the present invention, the first
In the above configuration, the tuner front-end section and the first and second digital demodulation sections are provided on the same substrate.

According to such a configuration, the digital satellite broadcast receiving tuner has a tuner front-end unit, a BS digital demodulation unit, and a CS digital demodulation unit on a single board, so that the circuit is accommodated in a small space. Can be.

Further, in the third configuration of the present invention, the second configuration
In the above configuration, the substrate is housed in a chassis.
According to such a configuration, since the digital satellite broadcast receiving tuner houses the substrate in, for example, a metal chassis, noise generated by a local oscillator or the like built in the tuner front-end unit is cut off by the chassis. Can be.

Further, in the fourth configuration of the present invention, the first
In any one of the configurations (1) to (3), a data combination unit that joins data output from the first and second digital demodulation units is provided.

According to such a configuration, the digital satellite broadcast receiving tuner combines the data output from the first and second digital demodulation sections in the data connection section using a three-state buffer or the like, and shares the common terminal. Since the output is increased, the number of terminals provided in the digital satellite broadcast receiving tuner can be reduced.

Further, in the fifth configuration of the present invention, the first
In any one of the above structures to the fourth structure,
An IQ signal branching unit for switching an output destination to either the first digital demodulation unit or the second digital demodulation unit according to a control signal input from the outside with a / Q signal is provided.

According to such a configuration, the digital satellite broadcast receiving tuner can switch the supply destination of the I / Q signal by the IQ signal branching unit using the buffer or the like of the tuner front end unit according to the signal to be demodulated.

In a sixth configuration of the present invention, a first tuner front-end section for selecting a first high-frequency signal of a received satellite broadcast and performing I / Q demodulation, and the first tuner front section. A first digital demodulation section for performing demodulation processing on an I / Q signal output from an end section, and a second tuner for performing channel selection and I / Q demodulation of a second high-frequency signal of a received satellite broadcast. A front end unit and a second digital demodulation unit that performs demodulation processing on an I / Q signal output from the second tuner front end unit are provided.

According to such a configuration, since the digital satellite broadcast receiving tuner uses a common circuit in the tuner front-end section, the number of components required for the circuit can be greatly reduced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> An embodiment of the present invention will be described below. FIG. 1 is a block diagram of a digital satellite broadcast receiving tuner of the first embodiment. The digital satellite broadcast receiving tuner of the present embodiment can process signals of both BS digital broadcast and CS digital broadcast. All circuits of the digital satellite broadcast receiving tuner are provided on the same substrate 1. The digital satellite broadcast receiving tuner controls BS / CS digital broadcast selection and channel selection by a controller 8 provided outside. Note that the BS digital broadcast and the CS digital broadcast have different modulation schemes.

A high frequency signal (RF signal) of a BS digital broadcast or a CS digital broadcast received by an antenna (not shown) is input from an input terminal 2 to a tuner front end unit 3. In the tuner front end unit 3, tuning of a high frequency signal and I / Q demodulation are performed. As a result, an I / Q signal is output from the tuner front end unit 3. I / Q output from tuner front end unit 3
The signal is split by the IQ signal splitter 4 under the control of the controller 8 and output to one of the BS digital demodulator 5 and the CS digital demodulator 6.

At the time of receiving a BS digital broadcast, an I / Q signal is input to the BS digital demodulation unit 5, where the I / Q signal is subjected to demodulation processing and the transport stream data is output. The transport stream data includes 1-byte parallel data D0 to D7, a signal STR_OUT indicating the beginning of a data packet, and data D0 to D0.
D7 clock BYTE_CLK. At this time, since the CS digital demodulation unit 6 is in an inactive state, the controller 8 turns off the power of the CS digital demodulation unit 6. Thereby, power consumption is reduced.

On the other hand, when receiving a CS digital broadcast,
The I / Q signal is input to the digital demodulation unit 6, demodulated by the CS digital demodulation unit 6, and the transport stream data having the same configuration as described above is output.

The transport stream data output from the BS digital demodulation unit 5 and the CS digital demodulation unit 6 are combined by a transport data output coupling unit 7 and output from a common terminal. The transport stream data output from the digital satellite broadcast receiving tuner in this manner is MPEG-demodulated by, for example, an MPEG demodulation circuit (not shown), whereby a video signal is reproduced. At this time, the power is turned off by the controller 8 because the BS digital demodulation unit 5 is in an inactive state.

The tuner front end unit 3 and the transport data output coupling unit 7 are controlled by a controller 8 as described later. The IQ signal branching unit 4, the BS digital demodulation unit 5, the CS digital demodulation unit 6, and the transport data output coupling unit 7 are each an integrated circuit (IC).
cuit).

Next, the internal configuration of the tuner front end unit 3 will be described. FIG. 2 is a block diagram showing the internal configuration of the tuner front end unit 3. The high-frequency signal input to the tuner front-end unit 3 is first input to the tuning circuit 10, and tuning is performed under the control of the controller 8.

The intermediate frequency signal (IF signal) output from the tuning circuit 10 is a SAW (Surface Acoustic Wav).
e) The pass band is limited by the filter 11 and the IQ demodulation unit 1
Sent to 2. The pass band of the SAW filter 11 is switched under the control of the controller 8 when receiving the BS digital broadcast and when receiving the CS digital broadcast. The IQ demodulation unit 12 uses the local signal oscillated from the local oscillator 15 to
/ Q demodulation, and outputs an I signal and a Q signal.

FIG. 3 is a circuit diagram showing the internal configuration of the IQ signal branching unit 4. The I signal input from the tuner front end unit 3 is input to buffers 20 and 21, and the Q signal is input to buffers 22 and 23. The control signal input from the controller 8 (see FIG. 1) is directly input to the enable input terminals of the buffers 20 and 22.
Buffers 21 and 23 are input to enable input terminals via inverters 24 and 25.

Therefore, when receiving the BS digital broadcast, the buffers 20 and 22 are enabled, and the I / Q signal is output to the BS digital demodulation unit 5 (see FIG. 1).
At this time, the buffers 21 and 23 are turned off. On the other hand, when receiving the CS digital broadcast, the buffers 21 and 23
Is enabled, and an I / Q signal is output to the CS digital demodulation unit 6 (see FIG. 1). At this time, buffer 2
0 and 22 are turned off.

FIG. 4 shows a transport data output coupling unit 7.
FIG. 2 is a circuit diagram showing an internal configuration of the device. CS digital demodulation unit 5
1-byte parallel data D0... D of the transport stream data transmitted from the
7 are input to the three-state buffers 30. The clock BYTE_CLK is input to the three-state buffer 32. The signal STR_OUT is input to the three-state buffer 33.

The BS digital demodulation unit 6 (see FIG. 1)
The parallel data D0... D7 of the transport stream data sent from the. Clock BYT
E_CLK is input to the three-state buffer 36. The signal STR_OUT is a three-state buffer 3
7 is input.

Further, a control signal from the controller 8 (see FIG. 1) is input to the transport data output coupling section 7. This control signal is directly input to the enable input terminals of the three-state buffers 30,... 31, 32, 33. 35, 36, and 37 are input to an enable input terminal via an inverter 38.

When receiving the BS digital broadcast, the three-state buffers 30,... 31, 32, 33 are turned off, and the three-state buffers 34,. On the other hand, when receiving CS digital broadcasting, three-state buffers 30,.
3 is enabled, and the three-state buffers 34... 35, 36, and 37 are turned off. Then, the outputs of the three-state buffers 30 and 34 are shared and output from the transport data combining unit 7.

Here, the three-state buffer means that when one of the buffers is turned on and the other buffer is turned off to output the transport stream data from the transport data output coupling unit 7, the three-state buffers are in an operating state of each other. Buffer that is not affected by
For example, regarding the data D0, one of the buffers 30 and 34 is enabled by the control signal, and the other is turned off. On the enabled side, the data D0 is independent of the operation state. Can be output.

The substrate 1 is housed in a metal chassis 40 as shown in FIG. As a result, noise generated by the local oscillator 15 or the like of the tuner front end unit 3 is shielded by the chassis 40, so that other components and circuits are not affected by the noise.

As described above, one digital satellite broadcast receiving tuner according to the present embodiment is used for BS digital broadcasting and C
Both S digital broadcasts can be decoded. In addition, since the tuner front-end section 3 occupying most of the circuit components of the digital satellite broadcast receiving tuner is shared by the BS digital broadcast and the CS digital broadcast, the number of components is significantly larger than that of the conventional tuner (see FIG. 8). Can be reduced. For this reason, the size of the tuner can be reduced.

<Second Embodiment> Next, a second embodiment of the present invention will be described. FIG. 6 is a block diagram of a digital satellite broadcast receiving tuner according to the second embodiment. The tuner front end unit 3 and the BS / CS digital demodulation unit 52 are provided on the substrate 50. The BS / CS digital demodulation unit 52 is the same as that of the first embodiment shown in FIG.
This is an IC in which a circuit having both functions of the BS digital demodulation unit 5 and the CS digital demodulation unit 6 is integrated into one chip.

A high-frequency signal (RF signal) of a BS digital broadcast or a CS digital broadcast is input from an input terminal 2 to a tuner front-end unit 3, where channel selection and I / Q demodulation are performed. Then, the I signal and the Q signal output from the tuner front end unit 3 are transmitted to the BS / CS digital demodulation unit 5.
2 is input.

Tuner front end 3 and BS / CS
The digital demodulation unit 52 is controlled by the controller 8. According to BS digital broadcasting or CS digital broadcasting,
As in the first embodiment, decoding and error correction are performed in each broadcasting mode, and transport stream data is output from a digital satellite broadcast receiving tuner. The transport stream data is 1 byte of parallel data D0 to D7, as in the first embodiment.
And a signal STR_OUT indicating the beginning of a data packet
And a clock BYTE_CLK of data D0 to D7.

As described above, in the present embodiment, the BS digital signal and the CS digital signal can be decoded by the BS / CS digital demodulation unit 52 formed into one chip, so that the required number of parts is reduced by the first number. Can be further reduced than in the embodiment.

<Third Embodiment> Next, a third embodiment of the present invention will be described. FIG. 7 is a block diagram of a digital satellite broadcast receiving tuner according to the third embodiment. BS
High frequency signals (RF signals) of digital broadcasting and CS digital broadcasting are input to digital satellite broadcast receiving tuners from input terminals 63 and 66, respectively.

The RF signal of the BS digital broadcast input from the input terminal 63 is subjected to channel selection and I / Q demodulation by a tuner front end unit 64. The I signal and the Q signal output from the tuner front end unit 64 are subjected to demodulation processing in the BS digital demodulation unit 65, and transport stream data is output from the digital satellite broadcast reception tuner.

The RF signal of the CS digital broadcast input from the input terminal 6 is subjected to channel selection and I / Q demodulation by the tuner front end section 67. The I signal and the Q signal output from the tuner front end section 67 are C
The demodulation processing is performed by the S digital demodulation unit 68, and the transport stream data is output. As in the first embodiment, the transport stream data includes 1-byte parallel data D0 to D7, a signal STR_OUT indicating the head of a data packet, and a clock BYTE_CLK of data D0 to D7.

In the present embodiment, the tuner front-end unit 6 uses the BS digital broadcast and the CS digital broadcast.
4 and 67 are provided separately, so that there is a disadvantage that the circuit scale becomes larger as compared with the first embodiment (FIG. 1). Also, since the input terminals 63 and 66 are provided separately, and the transport stream data is also provided separately for both the BS digital broadcast and the CS digital broadcast, there is a disadvantage that the number of terminals is increased. I have.

[0043]

<Effects of Claim 1> As described above, in the digital satellite broadcast receiving tuner according to the present invention, a tuner front-end unit for channel selection and I / Q demodulation is shared. Therefore, the number of parts can be significantly reduced as compared with the conventional tuner.

<Effect of Claim 2> In the digital satellite broadcast receiving tuner according to claim 2, since the tuner front end section and the digital demodulation section are provided on the same substrate, circuits are arranged in the space. can do.

<Effect of Claim 3> In the digital satellite broadcast receiving tuner according to claim 3, since the circuit is housed in, for example, a metal chassis, noise generated by the tuner is shielded by the chassis. , And does not affect external circuits and the like.

<Effect of Claim 4> In the digital satellite broadcast receiving tuner according to the present invention, each data is combined by a digital demodulation unit at a data combining unit using a three-state buffer, for example. Since the signals are output from a digital satellite broadcast receiving tuner, the number of terminals can be reduced.

<Effect of Claim 5> In the digital satellite broadcast receiving tuner according to claim 6, the I / Q signal output from the tuner front end section is a control signal according to the type of the received signal. Since an IQ signal branching unit that switches the output destination to the demodulation unit using a buffer or the like is provided, power consumption can be reduced by, for example, turning off the power of the demodulation unit that is in an inactive state.

<Effect of Claim 6> In the digital satellite broadcast receiving tuner according to claim 6, for example, BS
A tuner front-end unit and a digital demodulation unit are provided so that high-frequency signals of both digital broadcasting and CS digital broadcasting can be processed, so that two types of digital satellite broadcasting signals can be demodulated. .

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital satellite broadcast receiving tuner according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a tuner front-end section of the digital satellite broadcast receiving tuner.

FIG. 3 I / Q of the digital satellite broadcast receiving tuner
FIG. 4 is a circuit diagram showing an internal configuration of a signal branching unit.

FIG. 4 is a circuit diagram showing an internal configuration of a transport data output coupling unit of the digital satellite broadcast receiving tuner.

FIG. 5 is a diagram showing an appearance of the digital satellite broadcast receiving tuner.

FIG. 6 is a block diagram of a digital satellite broadcast receiving tuner according to a second embodiment of the present invention.

FIG. 7 is a block diagram of a digital satellite broadcast receiving tuner according to a third embodiment of the present invention.

FIG. 8 is a block diagram of a conventional BS digital satellite broadcast receiving tuner and a CS digital satellite broadcast receiving tuner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Input terminal 3 Tuner front end part 4 IQ signal branch part 5 BS digital demodulation part 6 CS digital demodulation part 7 Transport data output coupling part 8 Controller 10 Tuning circuit 11 SAW filter 12 IQ demodulation part 15 Local oscillator 20- 23 Buffer 24, 25 Inverter 30-37 Three-state buffer 38 Inverter 40 Chassis 52 BS / CS digital demodulation unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 7/20 H04N 7/20

Claims (6)

[Claims] 1. A tuner front end section for selecting a received high frequency signal of a satellite broadcast and performing I / Q demodulation, and a first demodulation for an I / Q signal output from the tuner front end section. A digital satellite broadcast receiving tuner, comprising: a first digital demodulation unit for performing a process; and a second digital demodulation unit for performing a second demodulation process on the I / Q signal. 2. The digital satellite broadcast receiving tuner according to claim 1, wherein said tuner front end section and said first and second digital demodulation sections are provided on the same substrate. 3. The digital satellite broadcast receiving tuner according to claim 2, wherein said board is housed in a chassis. 4. The digital satellite broadcast according to claim 1, further comprising a data combining unit that combines data output from the first and second digital demodulation units. Receive tuner. 5. An IQ signal branching unit for switching an output destination of the I / Q signal to one of the first digital demodulation unit and the second digital demodulation unit according to a control signal input from the outside. The digital satellite broadcast receiving tuner according to any one of claims 1 to 4, wherein: 6. A first tuner front-end unit for selecting a first high-frequency signal of a received satellite broadcast and performing I / Q demodulation, and an I / Q output from the first tuner front-end unit. A first digital demodulation unit for performing demodulation processing on a signal, a second tuner front end unit for performing channel selection and I / Q demodulation of a second high frequency signal of a received satellite broadcast, and the second tuner front end unit. A digital satellite broadcast receiving tuner, comprising: a second digital demodulation unit that performs demodulation processing on an I / Q signal output from a tuner front end unit.