JPS62168476A - Electric field strength display device - Google Patents

Abstract

PURPOSE:To easily decide a degree of a receiving state by detecting an RFAGC voltage which is varied in accordance with an electric field strength level, deciding the electric field strength level therefrom and displaying it on a display. CONSTITUTION:A video signal processing circuit 3 detects an RFAGG v voltage at the time when some channel has been selected by a channel selecting circuit 7, and sends this voltage to an electric field strength detecting circuit 9. The electric field strength detecting circuit 9 decides an electric field strength of its channel from a channel number obtained from the channel selecting circuit 7 and an electric field strength level obtained from comparing circuit 8, and sends electric field strength display data (the channel number and the electric field strength level) to an image displaying circuit 10. The image displaying circuit 10 is provided with a CPU and a memory, accumulates temporarily this data in the memory and also, sends a switching signal of a television screen and an electric field strength display data screen, to an image signal switching circuit 11, and executes an electric field strength display on a display 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a television receiver that receives television broadcast waves and displays images and sounds. Related to an electric field strength display device that displays the intensity level on a display in an easy-to-understand way A television receiver is used that has an automatic channel selection device that stops, displays, and receives the channel.

Problems that the invention aims to solve However, when a conventional television receiver is installed in a car, etc., the reception location changes constantly, so it is difficult to know which channels can be received and how well the channels are received. There is an inconvenience in that the user has to search among all channels to receive the signal each time.

The present invention eliminates such conventional drawbacks and automatically detects receivable channel numbers and their field strength levels even if the receiving location changes, stores these data, and immediately stores them when desired. The present invention provides a field strength display device that can display the channel number and field strength level on a display.

Means for Solving the Problems In the television field strength display device of the present invention, the field strength level of the television broadcast waves changes according to the channel selected by the television receiver that receives and displays the television broadcast waves. A field strength detection circuit determines the field strength level of the channel according to the level of this signal, and displays the field strength level along with the channel/channel number. At the same time, this data is stored in the memory circuit,
The electric field intensity level can be read out and displayed, so that the electric field intensity level can be immediately displayed on the display without having to detect the electric field intensity level each time it is displayed.

According to the television field strength display device of the present invention, a signal that changes according to the field strength level is input, and the field strength detection circuit determines the field strength level, and also displays the selected channel number and the channel number. The electric field strength level is stored in the memory circuit, read out, and converted into an image signal by the image display circuit, which is then displayed on the display. Therefore, each time the electric field strength is displayed, the electric field strength level can be displayed without having to detect it. , the field strength level can be immediately displayed on the display, allowing the user to easily determine the level of reception conditions.

Embodiment - Hereinafter, a television field strength display device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a television field strength display device according to the present invention. Television broadcast radio waves are converted into electrical signals by an antenna 1 and applied to a television tuner 2.

The xF multiplied signal, which is the output of the television tuner 2, is converted into an image signal by the video signal processing circuit 3. The video signal processing circuit 3 includes a video IF amplification circuit 4, a video detection circuit 6, a video amplification circuit 6, and the like.

7 is a tuning circuit that applies a tuning voltage and band switching voltage to the TV tuner 2, sequentially changes the tuning voltage, and monitors the AFC voltage, horizontal pulse signal, etc., and outputs a channel that tunes broadcast radio waves at a constant level. It has a built-in automatic tuning circuit that stops only the / channel.

Reference numeral 8 denotes a comparison circuit, which determines the signal level according to the magnitude of the voltage from the video signal processing circuit 3, such as RF AGC or IFAGC, which changes according to the electric field strength. The comparison circuit 8 is an A/D converter that converts an analog voltage into a digital signal.
It consists of a converter/verter, a voltage comparator that compares the magnitude of voltage, etc. 9 is an electric field strength detection circuit, and a tuning circuit 7
sends a tuning search start signal to start automatic tuning,
01o is an arithmetic processing circuit composed of a microcomputer, etc., which obtains the selected channel number from the channel selection circuit 7, obtains the electric field strength level from the comparison circuit 8, and determines the channel number and the electric field strength level. An example of an image display circuit is shown in FIG. 2. A CPU 1oA of a microcomputer, etc., a ROM 1oB 7'1-ROM 1oB that stores a program for operating the CPU 10A, and a RAM 1oC that temporarily stores data necessary for calculations.
and VRAM1, which is an image memory that stores image data.
oD, MPXloE, a multiplexer that switches calculation timing and display timing, and V RAM 10
Data is transferred between the CRT CloF that controls the D-no-F-column to enable writing and reading, the display circuit 10G that converts this output into a video signal, the electric field strength detection circuit 9 and the image signal switching circuit 11. Ilo exchanges and controls
It is composed of a circuit 10H. The image signal switching circuit 11 switches between the video signal of the video amplification circuit 6 that receives television broadcasting and the video signal of the image display circuit 10, or switches two video signals for simultaneous display in superimposition.

A display 12 displays the video signal as an image on a CRT or liquid crystal display.

Reference numeral 13 denotes operation switches, which are a group of input switches for normal channel selection operations and field strength display.

Next, the operation of an embodiment of the television field strength display device of the present invention will be described.

When a TV field strength display instruction is input using the operation switch 13, the channel selection circuit notifies the field strength detection circuit 9 of the field strength display mode and starts automatic channel selection for sequentially switching channels. In the case of domestic TV broadcasts in Japan, the user selects channels from channel 1, and then changes channels one by one until channels 62 are selected. During this time, the signal level of each channel is detected. - As an example, the relationship between RFAGC voltage and RF signal level is shown in FIG. When the electric field strength of television broadcasting exceeds 45 dB, the RFAGC voltage gradually decreases, and the RFAGC voltage, which was 8.0 ■ under an a es dB electric field, drops to 4.0 ■ under an e o dB electric field.
It is OV. In general, television broadcasting can display a beautiful screen with a good signal to noise ratio in an electric field of 60 dB, but when the electric field strength decreases to about 4 seconds dB, the image becomes contaminated with noise, and when the electric field strength decreases further to about 30 dB, color signals are reproduced. I can't, so the screen is black and white.

When automatically stopping TV broadcasting with automatic channel selection, use AFC.
The S-curve, horizontal pulse, horizontal synchronization signal, etc. of the signal are detected and the system is stopped at channels with TV broadcasting waves with an electric field strength of around 2 s dB or higher, but this method is well known and will therefore be omitted. do.

As described above, the voltage of the RFAGC when a channel is selected as a channel selection circuit is detected, this voltage is read by the comparator circuit 8 using an A/D converter or a comparator, and the voltage is sent to the field strength detection circuit 9 according to the field strength level. Apply the signal.

The voltage intensity detection circuit 9 determines the electric field intensity of the channel from the channel number obtained from the channel selection circuit 7 and the electric field intensity level obtained from the comparison circuit 8. By repeating this process sequentially from channel 1 to channel 62, receivable channels and their electric field strength levels can be determined.

The field strength display data (channel number and field strength level) of the field strength detection circuit 9 is notified to the CPU 1oA through the I10 circuit 1oH of the image display circuit 10. CPU
1oA stores this data in the RAM 1oC of the memory and converts it into image data and writes it to the VRAM 1oD of the image memory. When the tuning circuit A finishes measuring the electric field strength of all channels, it stops automatic tuning and returns the selected channel. Select the selected channel. The CPU 1oA of the image display circuit 10 that receives field strength display data from the field strength detection circuit 9 controls the image signal switching circuit 1.
1, by sending out a switching signal for switching from a television broadcast video signal to a video signal of field strength display data, the field strength of the television broadcast is displayed on the display 12. As a display example, channels that automatically stop tuning when the RFAGC voltage is 7.6■ or higher have a weak electric field strength of 7.6V.
~a, oV has medium N field strength, 4. oV or less i'1. can be displayed in text such that the field strength is strong.

In the above embodiment, the electric field strength is determined by the RFAGC voltage, but the electric field strength can also be determined by the IFAGC voltage, the magnitude of the video IF signal, etc., and the electric field strength can be determined by using one or more of these in combination. , it is clear that the present invention also includes displaying the following.

Further, in addition to displaying strong and medium 2 weak, it is also possible to display the electric field strength level in analog form using a bar graph or the like.

FIG. 4 shows an example of an electric field strength display screen displayed on the display 12. Here, the strength mentioned above.

An example is shown in which middle 1st grade characters are displayed adjacent to the channel number.

By looking at this field strength display screen, it is possible to select a television broadcast based on the currently receivable channel number and the field strength level of that channel.

Here, in order to judge the electric field strength from channel 1 to channel 62, the channels are sequentially switched and the signal level of that channel is judged, so it takes time for the signal level to stabilize, and all the electric field strengths It takes about 1 minute to judge the level. Therefore, store the channel number and field strength level in VRAM1 of the image memory.
It is stored in oD, RAM1oC of memory, etc. Then, by operating the field strength call switch provided on the operation switch 13, the memorized channel number and its field strength can be displayed without having to detect the field strength across all channels, allowing you to quickly obtain the desired value. This means that data can be obtained.

Effects of the Invention As described above, according to the television field strength display device of the present invention, the field strength of all channels of the television can be displayed for each channel on the display, and the radio wave reception status can be viewed. This data can be stored and recalled and displayed later.If it is adopted in an in-vehicle TV receiver, it will be possible to easily grasp the TV reception status even when moving to another city. You can select a station.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a field strength display device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of its image display circuit, and FIG.
The figure is a correlation diagram between the RFAGC voltage and electric field strength for determining the electric field strength level, and FIG. 4 is a front view of the display screen displaying the electric field strength level. 1...Antenna, 2...TV tuner, 3...Video signal processing circuit, 4...
Video IF amplification circuit, 6...Video detection circuit, 6.
...Video amplification circuit, 7...Tuition selection circuit, 8
...Comparison circuit, 9...-Field strength detection circuit, 10... Image display circuit, 11...
Image signal switching circuit, 12...Display, 1
3... Operation switch. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 → Electric field reception (dB) Figure 4

Claims (1)

[Claims] A television tuner that receives television broadcast radio waves and converts them into a video IF signal, a video signal processing circuit that converts the video IF signal into a video signal, and a video signal processing circuit that detects a signal that changes depending on the field strength level of the television broadcast radio waves. A comparison circuit that compares the magnitude with a reference value, a channel selection circuit that selects the signal of the desired channel from the TV tuner, and a signal corresponding to the channel number currently selected from the channel selection circuit. a field strength detection circuit that reads the field strength level from the circuit; a memory circuit that stores the channel number signal and field strength level read by the field strength detection circuit; and at least a channel number read from the memory circuit. It is equipped with an image display circuit that converts the signal and the electric field strength level into an image signal, and after detecting the channel number being selected and the electric field strength level of that channel and storing it in the memory circuit, the channel number and the electric field strength are displayed. An electric field strength display device that reads the level from the memory circuit and displays it on a display.