JPS6229223A - Receiver - Google Patents

Abstract

PURPOSE:To eliminate the need for provision of a muting period and to improve the accuracy of a display signal by measuring and storing an AGC control voltage at no signal in the power-on operation and the switching operation of a reception channel. CONSTITUTION:When a power is turned on and a new channel is selected through an input device 8, a systen controller 7 reads a frequency data N of a no signal channel from a nonvolatile memory 17 and supplies it to a reception circuit 5 via a tuner unit 6, and an AGC control voltage AGC (AGCN, AGCR) obtained at an AGC circuit of the reception circuit 5 is stored in a register of an A/D converter 15 while being revised. The AGC control voltage AGCN at no signal is given to a comparator 16, a difference voltage S16 between the AGC control voltage AGCR at signal reception and the AGC control voltage AGCN at no signal is obtained and fetched in the system controller 7 via an A/D converter 18. The system controller 7 displays the fetched digital signal S18 on a level meter 19.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a receiver, and in particular, to a receiver for forming a display signal used when adjusting the direction of a receiving antenna for receiving satellite broadcasting.

B. Summary of the Invention The present invention provides an AGC control voltage during no signal, which is performed in a receiver to form a display signal that displays the voltage difference between the AGC control voltage during no signal and the AGC control voltage when receiving a broadcast signal.
By measuring the @ control voltage when the reception start operation to receive the signal channel is performed, it is possible to interrupt reception of the signal channel and measure the AGC control voltage when there is no signal. It was designed to be eliminated.

C. Conventional technology Satellite broadcasting carries television signals using carrier waves in the SHF band, for example, and the directivity of the broadcast waves is sharp. Furthermore, when broadcast radio waves reach a receiving antenna, which is a parabolic antenna, they are weak.

Therefore, when installing a receiving antenna, it is desirable to adjust the receiving antenna so that it faces the direction in which the broadcast waves arrive so that it can receive television signals with high sensitivity.To make this adjustment, measure the reception level of the receiving antenna. and must be displayed.

By the way, the reception level V of the antenna is determined by the AGC (autoaatic
AG output from the gain control) circuit
C has a linear relationship with the control voltage AGC, and conventionally, A
GC? The receiving antenna was adjusted by measuring the 41J control voltage AGC. In addition, in order to properly adjust the measurement value so that changes in the reception environment such as weather conditions and the length of the cable from the reception antenna to the receiver do not affect the measurement value, we make adjustments when there is no signal, that is, when only noise arrives. The voltage difference between the AGC control voltage ACCM during signal reception and the AGC control voltage AGC during signal reception was measured.

In conventional receivers, such measurements are performed when the reception level measurement mode selection switch provided on the receiver is turned on.When the 0 selection switch is turned on, first the signal is not transmitted. When switching to a channel with no signal (hereinafter referred to as a no-signal channel),
The GC control voltage (hereinafter referred to as the AGC$ control voltage when there is no signal) is measured, that is, the A
Measure the GC control voltage ACCM, then switch to the original receiving channel (hereinafter referred to as the signal channel when it is a non-signal channel) and switch to the AG when receiving the broadcast signal.
CIIJ? 11 voltage AGC, and then measure the AGC control voltage AGC* when receiving a broadcast signal and the AGC when there is no signal.
! The difference between the control voltage AGCN and the control voltage AGCN is determined to form a display signal for adjusting the receiving antenna.

D Problems to be Solved by the Invention However, this measurement method has the disadvantage that once the selection switch is turned on, the signal channel is temporarily switched to a non-signal channel, and the image and sound are interrupted. At that time, there was a possibility that the user would feel uncomfortable.

Also, after turning on the selection switch, AG when there is no signal
Since the C1iII'a voltage AGCN is measured, the operating time from when the selection switch is turned on until the display signal is displayed is long.

Furthermore, AccIIJ due to noise? When the Il voltage AGC, is measured, this A c c II control voltage G is measured while the reception level measurement mode is selected.
C is continuously used, and even when the noise level changes, for example, it takes time to adjust the pointing direction of the parabolic antenna, it is applied as is, and there is a possibility that the receiving antenna cannot be adjusted in the appropriate direction.

The present invention has been made in consideration of the above points, and the Accll? There is no need to interrupt the image or video to measure the I voltage, and there is no need to interrupt the AGC when there is no signal.
The present invention aims to provide a receiver that can automatically update the control voltage to the latest one.

E Means for Solving Problem E To solve this problem, in the present invention, when a reception start operation is performed to receive a predetermined signal channel on which a broadcast signal is being transmitted, the broadcast signal is once transmitted. A when there is no signal by selecting a channel with no signal
GC control voltage A Measure and store CCM, select a predetermined signal channel, and set the AGC control voltage AG when receiving a broadcast signal.
A display signal 318 is generated to display the difference voltage between the AGC control voltage AGC,l when receiving a broadcast signal and the AGC control voltage AGC,l when there is no signal.

When a reception start operation is performed, such as when the F-action power supply is turned on or when the reception channel is switched, a non-signal channel is selected and the AGC control voltage AGC from the AGC circuit of the reception circuit 5 is applied.

Measurement and memorization are now possible. That is, the AGC control voltage AGCN is measured when there is no signal during a muting period that occurs when the power is turned on or when the channel is switched.

Therefore, it is possible to eliminate the need to intentionally form a muting period in order to measure the AGC control voltage ACCM when there is no signal.

Furthermore, since the AGC control voltage A G CN during no signal is measured every time the channel is switched, it is possible to obtain the display signal 318 using the latest AGCi 151I control voltage A G CN during no signal. As a result, it has become easier to adjust the direction of the receiving antenna 1 to the optimum direction.

Embodiment G An embodiment of the present invention will be described in detail below with reference to the drawings. 1st
In the figure, l is a satellite broadcasting receiving antenna consisting of a parabolic antenna, and the satellite broadcasting radio waves that arrive at this receiving antenna 1 are converted into a converter 2 at a frequency of, for example, 1 (GHz).
is converted into an intermediate frequency signal S2, and this signal S2 is applied to the receiving circuit 5 of the receiver 4 via the cable 3.

The receiving circuit 5 includes a high frequency amplification circuit, a frequency conversion circuit, a video intermediate frequency amplification circuit, an AGC circuit, an AFT (automatic
tc frequency tuning) circuit, etc., and outputs a television signal DET of a predetermined channel detected in response to a local oscillation signal S6 given from a tuner unit 6 having a PLL frequency synthesizer circuit configuration.

The system controller 7 retrieves frequency data N from the non-volatile memory 17 in response to a reception channel command given from an input device 8 having a key matrix circuit configuration, supplies it to the tuner unit 6, and transmits the television signal DET of a predetermined channel to the reception circuit 5. make a fist-eating wave. In addition, the system controller 7 transmits the AFT signal from the AFT circuit of the receiving circuit 5.
The signal AFT is taken in, the frequency data N is corrected according to the AFT signal AFT, and the local oscillation signal S6 is controlled so that the television signal of a predetermined channel can be detected.

The television signal DET of the predetermined channel detected in the reception circuit 5 in this manner is provided to a video detection circuit 9 and an audio detection circuit 10.

The video detection circuit 9 has a filter configuration, extracts the video signal VID from the incoming television signal, and supplies it to the video signal circuit 11. The video signal circuit 11 converts the video signal VID into a signal for driving the CRT display section of the display device 12, and supplies the signal to the CRT display section of the display device 12 via the mixing circuit 13 for display.

The audio detection circuit 10 has a filter configuration, and extracts an audio signal AUD from an incoming television signal and supplies it to the speaker section of the display device 12 via the audio signal circuit 14 to generate audio.

In addition to the above configuration, the receiver 4 has the following configuration for measuring and displaying the reception level.

When the system controller 7 is turned on,
When a new channel is selected through the input device 8, the frequency data N of the non-signal channel is read out from the non-volatile memory 17 and applied to the tuner unit 6, and then immediately converted into a successive approximation type analog-to-digital converter (A /D converter) Reset signal R3T to 15
give l.

The A/D converter 15 converts the AGC control voltage AGC (AGCs 1AG
When the reset signal R3Tl arrives, the AGC$II control voltage AGC is converted into a digital signal, updated and stored in a built-in register.

At the time when the reset signal R3T1 arrives, the AGC control voltage AGCN of the no-signal channel is given to the A/D converter 15, and the built-in register of the A/D converter 15 stores this AGC control voltage AGCN at the time of no signal. It turns out.

The analog output terminal of the A/D converter 15 outputs an analog signal obtained by converting the digital data stored in the built-in register into an analog signal, that is, the A signal when there is no signal.
GC! The II control voltage AGCN is output and applied to the comparator 16 as a first comparison input.

Further, the comparator 16 receives the AGC control voltage AG from the receiving circuit 5.
C is given as the second comparison input.

Thus, when the signal is received by the comparator 16 for the television signal currently being received, the AcCtbll? Il voltage A
A difference voltage 316 between the AGC control voltage AGCN and the AGC control voltage AGCN at the time of no signal is obtained, and this is converted to a digital signal 318 via the A/D converter 18, for example, 100 (m
sec) is taken into the system controller 7.

The system controller 7 receives the digital signal 3
18, a level meter 19 made of a display element for displaying a bar graph, for example, is displayed. Further, when the screen display mode is selected by the input panel M8, the system controller 7 supplies the character generator 20 with a character generation signal CHA corresponding to the digital signal 318, and generates a number corresponding to the level value represented by the digital signal S18. A character signal S20 is output from the character generator 20 to the mixing circuit 13. In the mixing circuit 13, the video signal VID via the video signal circuit 11 is mixed with the several character signal S20 and given to the CRT display section of the display device 12, and the level value represented by the digital signal 31B is, for example, a number of characters and a bar graph. The image is superimposed and displayed on the screen.

Note that when the power is turned on, the system controller 7 provides a reset signal RST2 to the A/D converter 18 to cause it to perform an initial reset operation.

In the receiver having the above configuration, AGC when there is no signal
A G C'f when receiving a signal for the control voltage AGC,
WI? The operation of measuring and displaying the magnitude of the 11 voltage AGCI is performed according to the processing procedure shown in FIG.

That is, when NR is turned on, the system controller 7 starts the program in step SP1, moves to the next step SP2, gives the frequency data N of the non-signal channel to the tuner unit 6, and tunes the non-signal channel. Let them select a channel.

Next, proceeding to step SP3, the A/D converter 15
A reset signal R3Tl is sent to the A/D converter 15 to reset the AGC control voltage when receiving a no-signal channel, that is, the AGC [control voltage AGCN when there is no signal].
Let it be taken into account.

In this way, ACCI when there is no signal! 4m voltage ACC
After measuring M, the system controller 7 moves to the next step SP4 and retrieves the frequency data N of the last channel selected at the time of the power-off operation from the nonvolatile memory 17.
is taken in and given to the tuner unit 6 to select the last channel.

Next, the process moves to step SP5, and after reading the key state of the input device 8, it is determined in step SP6 whether or not the channel has been switched. This step SP
6, if a negative result is obtained, the next step SP
7, it is determined whether the built-in timer has measured 100 (msec).

On the other hand, if a positive result is obtained by performing the channel switching operation in step SP6,
In step SP8, frequency data N corresponding to the no-signal channel is given to the tuner unit 6 to cause the receiving circuit 5 to tune the no-signal channel. After that, step SP
9, a reset signal R3T is applied to the A/D converter 15.
1 is sent to update and store the AGC control voltage AGC when there is no signal. Then, the process moves to step 5 PIO, where the frequency data N of the switched channel is sent out to tune the switched channel, and then the process moves to step SP7, where the time measured by the timer is 100 (ms).
ec) is exceeded.

For example, when the first channel and the third channel are channels on which broadcast signals are being transmitted and the second channel is a non-signal channel, if a switching operation is performed from the first channel to the third channel, the system controller 7 selects the second channel, which is a non-signal channel, in step SP8, and imports the AGC control voltage at the time of receiving the second channel in step SP9.
The PIO selects the third channel, which is the switching channel, and controls the process to proceed to step SP7.

If a negative result is obtained in step SP7, the process returns to step SP5 described above. Eventually, 100 (m100(
, an affirmative result is obtained in step SP7, and at this time the system controller 7 executes the next step Sp
At H, digital data 318 is taken in from the A/D converter 18 according to the difference between the AGC control voltage AGC when receiving a broadcast signal and the AGC [i voltage AGC, when there is no signal], and the amount is taken in according to the digital data S1B. In step 5P12, the level meter 19 is updated and displayed.

Next, the process moves to step 5P13, and it is determined whether or not the screen display mode is selected based on the key state of the input device 18 read in step SP5.If a negative result is obtained, the process returns to step SP5, and if a positive result is obtained. If so, the process moves to step 5P14 and the character generation signal CIA corresponding to the digital data 318 is sent to the character generator 2.
0 to display on the CRT display section of the display device 12.

According to the above processing procedure, since a negative result is obtained in step SP6 from the power-on operation to the first channel switching operation, the AGC during the no-signal period immediately after the power-on operation measured in step SP2 Control voltage A
G Differential voltage with reference to CN A G C* A G
CM is obtained and displayed on the level meter 19 or display device 12 every 100 (msec).

When there is a channel switching operation, an affirmative result is obtained in step SP6, so that in step SP9 the AG (JIIJI voltage A
GC, and until the next channel switching operation, the differential voltage AGC*AGCM based on the AGC control voltage ACCM due to this noise is displayed on the level meter 19 or display device 12 every 100 (msec). be done.

When using the above receiver to adjust the direction of the receiving antenna 1, the user operates the input device 8 to select the screen display mode, and displays the differential voltage displayed on the screen on the display device 12. While checking the values of AGC and -ACCM, the azimuth and elevation angle of the receiving antenna 1 may be adjusted and fixed in the direction that maximizes the value of the differential voltage.

Here, as shown in the display device 12 of FIG. Maximum differential voltage obtained during operation of AGC*
By displaying the AGCM (r40J in the figure) at the same time, even if the rotation is excessive, it can be easily adjusted to the optimal position.

As described above, according to this embodiment, since the value of the difference voltage between the AG (control voltage) is displayed when a signal is received and when there is no signal, the direction of the receiving antenna 1 can be easily set.

Therefore, the required no-signal voltage A
Since the GCN is measured when the power is turned on and when switching channels, there is no need to intentionally provide a muting period, and no interruption of images or audio occurs. In addition, the AGC control voltage A G C when there is no signal
Since # is updated at the above-mentioned opportunity, the error included in the displayed differential voltage can be made smaller than when it is not updated.

Furthermore, according to the embodiment shown in FIG. 1, the differential voltage is always displayed on the level meter 19, so that it can be easily checked visually if the direction of the receiving antenna 1 changes due to, for example, a gust of wind. can.

In addition to using the display by the level meter 19 for orientation adjustment, the user can also use it as a means of adjusting image quality such as contrast.

In addition, in the above description, the display unit includes the display device 12 and the level meter 19, but the display device 12
The receiving antenna 1 may have either one of a level meter 19 and a level meter 19, and the direction of the receiving antenna 1 can also be adjusted appropriately.

H Effects of the Invention As described above, according to the present invention, the AGC control voltage when there is no signal is 7! Since measurements are taken and stored when the X source is turned on and when the reception channel is switched, the A when there is no signal is
It is possible to obtain a receiver that does not require a muting period just to measure the GC control pressure, and can improve the precision of the display signal by updating the AGC control voltage when there is no signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the receiver according to the present invention, FIG. 2 is a flowchart showing the processing procedure of the system controller 7 in FIG. 1, and FIG. 3 shows the relationship between the reception level and the AGC control voltage. It is a route map shown. 1... Receiving antenna, 4... Receiver,
5... Receiving circuit, 6... Tuner unit, 7... System controller, 8...
...Input device, 12...Display bag f, l 5
, l 8...A/D converter, 16...
... Comparator, 19 ... Level meter, 20 ...
...Character generator. Reception level and ACC control voltage/I-B Sekiyou 3 Diagram

Claims (1)

[Claims] When a reception start operation is performed to receive a predetermined signal channel on which a broadcast signal is being transmitted, select a non-signal channel on which a broadcast signal is not being transmitted, measure and store the AGC control voltage when there is no signal. and measuring the AGC control voltage when the broadcast signal is received by selecting the predetermined signal channel, and displaying a voltage difference between the AGC control voltage when the broadcast signal is received and the AGC control voltage when the broadcast signal is received. A receiver characterized in that it is configured to form a