JP2003298436A - Broadcasting receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a broadcasting receiver in which an antenna is precisely installed even when a saturated state occurs in a receiving level detection value for antenna adjustment. <P>SOLUTION: The output characteristic of a C/N value detection circuit 3b is saturated approximately with a C/N value 18 dB, for example. A tuning microcomputer 5 applies an adjust signal for a local oscillation frequency from the side of an AFT circuit 2a to a PLL tuner circuit 1a to obtain a value corresponding to 14 dB, for example, as a C/N detection voltage value when adjusting the antenna (on the assumption that an AFT operation is stopped and the operation of noise reduction is stopped) to intentionally lower the C/N detection voltage value. In such a state, the fine adjustment of the antenna is implemented. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadcast receiver using an antenna for receiving weak radio waves such as satellite broadcasts with high directivity.

[0002]

2. Description of the Related Art An antenna for receiving satellite broadcasting has a parabolic shape for receiving weak radio waves from a satellite and has a high directivity. Therefore, when installing the antenna, it is necessary to accurately match the azimuth angle and the elevation angle so that the antenna faces the satellite position. Normally, the azimuth angle is adjusted based on the direction of the magnet, and the elevation angle is adjusted using the elevation scale of the mounting bracket or the protractor. At this stage, only the coarse adjustment of the antenna position was performed.After that, while confirming the screen and sound of the broadcast receiving device, the antenna direction was finely adjusted and the antenna was fixed in the best direction. Be done.

Further, in place of the screen and sound, a reception level detection value of a broadcast wave is generated, and antenna fine adjustment is often performed based on the display of the reception level detection value. A technique of using the AGC voltage of the tuner as a signal indicating the received level detection value (see Japanese Patent Publication No. 6-38564: IP
C H01Q 3/02) and C / N ratio are available. Since the C / N ratio is strongly related to received video and audio and high accuracy can be ensured in antenna adjustment, in recent years, the C / N ratio is more often used than the AGC voltage.

FIG. 6 is a block diagram showing a conventional BS broadcast receiving apparatus. The BS tuner circuit stage 11 includes a PLL tuning circuit 11a and the like, and generates an intermediate frequency signal (IF) of a broadcast wave of a channel instructed by the tuning microcomputer 15. The intermediate frequency (IF) circuit stage 12 includes a signal amplification circuit,
An AGC circuit, an auto fine tuning (AFT) circuit 12a, a detection circuit 12b and the like are provided. AFT circuit 12
a is PL so that the video intermediate frequency maintains a predetermined frequency.
A local oscillation frequency adjustment signal (AFT up request signal / AFT down request signal) is given to the L tuning circuit 11a. The detection circuit 12b performs video detection. The video processing circuit stage 13 produces a video signal by demodulation, and the audio processing circuit stage 14 produces an audio signal. C / N
The value detection circuit 13a generates a detection voltage value corresponding to the C / N ratio.

When the AGC is used for adjusting the antenna, the AGC voltage value from the AGC circuit is input to the A / D conversion port of the tuning microcomputer 15, and the tuning microcomputer 15 has a digital value AGC. The antenna adjustment display data is generated based on the voltage value and displayed on the screen.

When the C / N ratio is used for antenna adjustment, the detected voltage value corresponding to the C / N ratio from the C / N value detection circuit 13a is the A / D conversion port of the channel selection microcomputer 15. The tuning microcomputer 15 generates antenna adjustment display data based on the detected voltage value corresponding to the digitalized C / N ratio, and displays it on the screen.

[0007]

By the way, the above-mentioned C / N
If the value detection circuit 13a is a simple circuit (for example, a circuit that detects with a high-frequency simple BPF (bandpass filter)), as shown in FIG. 7, C / N ratio = 5 to 18
Although the detected voltage value rises in the vicinity of dB in proportion to the C / N ratio, the detected voltage value may saturate above it. In recent years, due to the improvement of antenna technology, the C / N ratio of 20 dB or more in standard BS antennas, large antennas, and even small BS antennas causes the detection voltage value to be in the saturation region, making precise installation of the antennas difficult. . Therefore, in actual reception after the antenna is installed, the C / N ratio of the broadcast signal of the reception channel may be significantly deteriorated due to weather changes such as rain and snow. In addition, the AGC voltage value from the AGC circuit and the C from the C / N value detection circuit 13a
The detected voltage value corresponding to the / N ratio is A / of the tuning microcomputer 15.
This is input to the D conversion port, which requires an extra wiring pattern, and this wiring pattern picks up a high frequency beat component. Then, it is necessary to take measures to add a coil and a condenser for this high frequency beat component.

In view of the above situation, the present invention enables precise installation of the antenna even when the reception level detection value for antenna adjustment is saturated, and the reception level detection value for antenna adjustment has a high frequency. An object of the present invention is to provide a broadcast receiving device that can be prevented from being affected by.

[0009]

In order to solve the above-mentioned problems, a broadcast receiving apparatus of the present invention comprises a channel selecting unit for setting a channel reception frequency, a unit for generating a reception level detection value of a broadcast wave, It is judged whether or not the reception level detection value is larger than a predetermined level, and when it is larger, the channel reception frequency in the channel selection means is controlled so as to be shifted so that the reception level detection value deteriorates to a predetermined level. And a control unit capable of returning to the channel selection process.

With the above configuration, even when the reception level detection value for antenna adjustment is saturated, the channel reception frequency in the channel selection means is shifted to deteriorate the reception level detection value to a predetermined level. You can By setting the predetermined level around a predetermined point (for example, a truncation noise start point) in the non-saturated area (linear area), the reception level detection value changes in the antenna direction fine adjustment. It enables precise installation of.

A message asking the user whether to perform antenna adjustment is displayed on the screen, and when an operation indicating that antenna adjustment is performed is performed, control is performed to deteriorate the reception level detection value to a predetermined level, and antenna adjustment is performed. It is preferable to be configured so as to return to the normal channel selection process when an operation indicating that the is finished is performed.

It is preferable that the automatic fine tuning means is provided and the automatic fine tuning process is stopped when the reception level detection value is deteriorated to a predetermined value level. Further, it is preferable that the apparatus is provided with noise reduction means and is configured to stop the noise reduction processing when the reception level detection value is deteriorated to a predetermined value level.

The process of shifting the channel reception frequency may be performed step by step in a predetermined width, and may be configured to shift a plurality of steps at a time when the difference between the reception level detection value and the predetermined level is a predetermined value or more.

The reception level detection value of the broadcast wave is input to the analog / digital conversion port of the IC constituting the channel selection means, and the control means is configured to receive the reception level detection value from the channel selection means as a digital value. May be. With such a configuration, the reception level detection value is input to the analog / digital conversion port of the IC that constitutes the channel selection means,
Since the control means receives the reception level detection value from the tuning means as a digital value, it is not necessary to route the wiring pattern in order to give the reception level detection value to the control means side, therefore, the high frequency beat component is not picked up, The measure becomes unnecessary.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A BS analog broadcast receiving apparatus according to an embodiment of the present invention will be described below with reference to FIGS.

The BS tuner circuit stage 1 is a high frequency circuit or a PL.
It is provided with an L tuning circuit 1a and the like. The high frequency circuit inputs and amplifies a BS-IF (intermediate frequency) signal from the BS antenna. The PLL tuning circuit 1a mixes a desired channel signal (broadcast wave) and a local oscillation signal to generate a second intermediate frequency signal (IF), and is formed as an IC circuit. The local oscillation signal is output from the PLL synthesizer. The PLL synthesizer generates a local oscillation signal that is changed corresponding to the signal of the desired channel so that a predetermined second intermediate frequency signal is generated from the mixer (mixer). The channel selection information of the desired channel is the channel selection microcomputer 5.
Given by.

The intermediate frequency (IF) circuit stage 2 includes a signal amplifier circuit, an AGC circuit, an auto fine tuning (AF) circuit.
T) The circuit 2a, the detection circuit 2b, etc. are provided. AFT circuit 2
a is PL so that the video intermediate frequency maintains a predetermined frequency.
The local tuning frequency adjustment signal (A
FT up request signal / AFT down request signal). The detection circuit 2b performs video detection.

The video processing circuit stage 3 produces a video signal by demodulation and the audio processing circuit stage 4 produces an audio signal. The noise reduction (NR) circuit 3a removes noise from the detected video signal. The C / N value detection circuit 3b generates a detection voltage value corresponding to the C / N ratio. C / N value detection circuit 3
b may be a simple circuit (for example, a circuit for detecting with a high-frequency simple BPF (bandpass filter)), and the detected voltage value may be saturated at a C / N ratio of 18 dB or more, for example.

In this embodiment, the C / N ratio is used for antenna adjustment. The detected voltage value corresponding to the C / N ratio from the C / N value detection circuit 3b is the PLL tuning circuit 1a.
Is input to the A / D conversion port. PLL tuning circuit 1a
Converts the detected voltage value input to the A / D conversion port into a digital value. When the detected voltage value is represented by a 4-bit digital value, 16 levels can be set as shown in FIG. Here, for example, the detected voltage value is 0.4375.
In the range of × Vcc to 0.5 × Vcc (Vcc = 5V), the 4-bit value is “0111”. Further, when the detected voltage value is to be a 3-bit digital value, as shown in FIG.

PLL tuning circuit 1a used in this embodiment
P7, P6, P5, P4, P3, P
There is a port of 0, and P6 is an A / D conversion port. The IIC bus is used for data transfer and command output control. FIG. 2A is an explanatory diagram showing the write data format in the IIC bus, and FIG.
It is explanatory drawing which showed the read data format in IC bus. The channel selection microcomputer 5 executes the read / write on the IIC bus to generate the PLL channel selection circuit 1
The detected voltage value ((A0, A1, A2 if it is a 3-bit digital value) converted into a digital value in a is received, and antenna adjustment display data is generated based on this detected voltage value and displayed on the screen.

If the output characteristic of the C / N value detection circuit 3b is as shown in FIG. 7 used in the conventional section, the C / N value at the approximately midpoint of the unsaturated region (linear region) is 14 dB. The detected voltage value corresponding to this C / N value = 14 dB is 2.5V. At this time, the detection voltage value received by the channel selection microcomputer 5 is “0111” as a 4-bit value (0.4375 × Vcc to 0.5 × Vcc (V in analog voltage.
cc = 5V))).

When the antenna is adjusted (AF
T operation stop, noise reduction operation stop), and when a 4-bit value larger than "0111" is received as the detection voltage value, the AFT circuit 2a side sends a signal for adjusting the local oscillation frequency to the PLL tuning circuit 1a. (AFT
Up request signal / AFT down request signal)
Are issued via the IIC bus so that This command is a 4-bit value "0111" as the detected voltage value.
Until you get. When "0111" is obtained as a 4-bit value as the detected voltage value, the tuning microcomputer 5 determines that the antenna fine adjustment should be performed.

The process relating to antenna adjustment will be described below with reference to the flowchart of FIG. When the broadcasting receiver is initially turned on (step S1),
For example, the antenna setting flag has been reset,
A message such as "Do you want to adjust the antenna?" Is displayed on the screen (step S2). When "YES" is selected by the user in the "YES" or "NO" button displayed together with this message, the tuning microcomputer 5 uses the empty port of the PLL tuning circuit 1a to perform noise reduction (NR). ) The noise reduction operation in the circuit 3a is stopped (step S3), and A in the AFT circuit 2a is further instructed by the tuning microcomputer 5's command.
The FT operation is stopped (step S4). The BS antenna has already been installed and has been roughly adjusted.

Next, the detected voltage value is 2.5 V or more (C / N
It is determined whether the value is 14 dB or more and the 4-bit value is "1000" or more) (step S5). If yes,
Furthermore, the detected voltage value is 2.8125V or more ("4bit value"
It is determined whether or not 1001 ″ or more) (step S6).
If NO in step S6, the local oscillation frequency adjustment signal (AFT up request signal / AFT down request signal) is shifted by one step (step S8). That is, the reception state is intentionally deteriorated. If YES in step S6, 2 is set in the local oscillation frequency adjustment signal (AFT up request signal / AFT down request signal).
The process of shifting by steps is performed (step S7 → step S8), and the process is performed quickly.

When the answer is NO in step S5, the current reception state is in the linear region in FIG. 7, and a message prompting the execution of the antenna precision adjustment is displayed on the screen (step S9). Upon receiving this message, the antenna adjuster will gradually change the orientation of the BS antenna. With this work, the detected voltage value is 2.5.
V (14 dB for C / N value, "0111" for 4-bit value)
It will change in the vicinity. The detected voltage value is displayed on the screen as a numerical value or a bar, and the antenna adjuster will firmly fix the orientation of the BS antenna when the highest detected voltage value is obtained. Thereafter, the antenna adjuster performs an operation on the broadcast receiving apparatus, which means that the adjustment is completed, and the broadcast receiving apparatus recognizes the end of the antenna (step S1
0). After the antenna adjustment, the AFT operation in the AFT circuit 2a and the noise reduction (NR) circuit 3a
The noise reduction operation in is turned on (step S11).

As described above, even when the detected voltage value for adjusting the BS antenna is saturated, the channel reception frequency in the PLL channel selection circuit 1a is shifted so that the detected voltage value becomes a non-saturated region (linear region). Can be set around a predetermined point (for example, the starting point of truncation noise), and in this setting state, the detected voltage value will change sensitively when the orientation of the BS antenna is adjusted. It will be possible.

Further, the C from the C / N value detection circuit 3b is used.
The detection voltage value corresponding to the / N ratio is input to the A / D conversion port of the PLL tuning circuit 1a, and the tuning microcomputer 5 receives the digitized detection voltage value from the PLL tuning circuit 1a. Such a configuration corresponds to the C from the C / N value detection circuit 3b.
The detected voltage value corresponding to the / N ratio is A / D of the tuning microcomputer 5
Compared to the configuration of inputting to the conversion port, there is an advantage that wiring is not required, and therefore, high frequency beat components are not picked up and countermeasures for them are also unnecessary.

In this embodiment, the C / N ratio is used for antenna adjustment, but the present invention can also be applied to a configuration in which the AGC voltage is used for antenna adjustment. Further, in this case, the tuning microcomputer 5 can receive the digitized AGC voltage from the PLL tuning circuit 1a.

[0029]

As described above, according to the present invention, it is possible to precisely install the antenna even when the reception level detection value for adjusting the antenna is saturated.
Further, it is possible to prevent a situation in which the reception level detection value for adjusting the antenna is affected by a high frequency.

[Brief description of drawings]

FIG. 1 is a block diagram showing a broadcast receiving device according to an embodiment of the present invention.

2 (a) is an explanatory diagram showing a write data format in the IIC bus, and FIG. 2 (b) shows I.
It is explanatory drawing which showed the read data format in IC bus.

FIG. 3 is an explanatory diagram showing a relationship between a detected voltage value (analog value) and a detected voltage value of a 4-bit digital value.

FIG. 4 is an explanatory diagram showing a relationship between a detected voltage value (analog value) and a detected voltage value of a 3-bit digital value.

FIG. 5 is a flowchart showing processing contents when an antenna of the broadcast receiving apparatus is installed.

FIG. 6 is a block diagram showing a conventional broadcast receiving apparatus.

FIG. 7 is a graph showing a detected voltage value (analog value) characteristic with respect to an actual C / N value (dB).

[Explanation of symbols]

1 BS tuner circuit stage 1a PLL tuning circuit 2 Intermediate frequency circuit stage 2a AFT circuit 2b Detection circuit 3 Video processing circuit 3a NR circuit 3b C / N detection circuit 4 Audio processing circuit 5 Channel selection microcomputer

Claims (7)

[Claims] 1. A channel selection means for setting a channel reception frequency, a means for generating a reception level detection value of a broadcast wave, and a judgment whether or not the reception level detection value is larger than a predetermined level. Sometimes, control means is provided so as to shift the channel reception frequency in the channel selection means so that the reception level detection value deteriorates to a predetermined level, and control means capable of returning to normal channel selection processing. Broadcast receiver. 2. The broadcast receiving apparatus according to claim 1, wherein a reception level is detected when a message asking the user whether to adjust the antenna is displayed on the screen and an operation indicating that the antenna is to be adjusted is performed. A broadcast receiving apparatus, characterized in that control is performed to deteriorate the value to a predetermined level, and when an operation indicating completion of antenna adjustment is performed, normal channel selection processing is resumed. 3. The broadcast receiving apparatus according to claim 1 or 2, further comprising an auto fine tuning means, and configured to stop the auto fine tuning process when the reception level detection value is deteriorated to a predetermined level. A broadcast receiving device characterized by the above. 4. The broadcast receiving apparatus according to claim 1, further comprising a noise reduction unit, and configured to stop the noise reduction process when the reception level detection value is deteriorated to a predetermined level. A broadcast receiving device characterized by being performed. 5. The broadcast receiving apparatus according to any one of claims 1 to 4, wherein the process of shifting the channel reception frequency is performed step by step with a predetermined width, while the difference between the reception level detection value and the predetermined level is A broadcast receiving apparatus, characterized in that it is configured to shift a plurality of steps at a time when the value is equal to or more than a predetermined value. 6. The broadcast receiving device according to claim 1, wherein the reception level detection value of the broadcast wave is input to an analog / digital conversion port of an IC constituting the channel selection means, and the control means. Is a broadcast receiving apparatus configured to receive a reception level detection value as a digital value from the channel selection means. 7. A broadcast receiving apparatus comprising: a channel selection unit for setting a channel reception frequency; a unit for generating a reception level detection value of a broadcast wave; and a control unit for controlling the channel selection unit. The reception level detection value of the broadcast wave is input to the analog / digital conversion port of the IC constituting the means, and the control means is configured to receive the reception level detection value as a digital value from the tuning means. Broadcast receiver.