JPH04119180U - In-vehicle TV diversity device - Google Patents

Abstract

(57) [Summary] [Purpose] To significantly reduce audio switching noise caused by antenna switching. [Structure] For example, by providing a diversity processing circuit corresponding to the video system and audio system from the antenna with the best reception condition among multiple antennas, and also by providing a diversity processing circuit corresponding to the video system and audio system, high frequency signals are By independently providing a video front end that converts into a frequency signal and an audio front end, audio switching noise caused by video diversity antenna switching is reduced.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to in-vehicle TV diversity equipment, and is particularly applicable to not only video signals. In-vehicle TV diversity equipment that reduces switching noise even when it comes to audio signals. related.

0002

[Conventional technology]

In an in-vehicle TV diversity device, the optimum reception among multiple antennas is selected. A video diversity system that receives signals by sequentially switching the antennas that are in the receiving state. equipment is used. An example of the configuration of a conventional in-vehicle television diversity device is shown in FIG. In FIG. 2, a plurality of antennas 1 (in this example, four antennas 1A to 1D) are each It is connected to the input terminals 2A to 2D of the video diversity circuit 2, and the video signal is Compare each antenna output during the blanking period of the signal and select the best reception based on the comparison results. Sends the received signal from the state antenna to the front end (TV F/E) 4. . The output of the front end 4 is detected by the video detection circuit 7, and a video signal is output. At the same time, the output signal from the video detection circuit 7 is used to perform video diversity detection. The switching timing signal of the digital circuit 2 is output. Output signal from front end 4 is mixed with the oscillation signal from the reference oscillator 6 in the mixing circuit 5, and the audio detection circuit 8, the audio is detected and an audio signal is obtained.

0003

[Problem that the idea aims to solve]

As mentioned above, conventional in-vehicle TV diversity devices are Comparison of antenna output during the video signal blanking period, Since the antenna is switched, the noise associated with the switching does not appear on the screen. stomach. However, audio signals are basically independent from video signals; Since the blanking period is also continuous, the noise caused by antenna switching is The noise appears in the audio signal, making it very difficult to hear and causing auditory problems.

0004 Therefore, the purpose of this invention was to improve the antenna switching for video diversity. In-vehicle TV diversity device that significantly reduces audio switching noise caused by Our goal is to provide the following.

[0005]

[Means to solve the problem]

In order to solve the above-mentioned problems, we developed an in-vehicle TV diversity device based on this invention. teeth, Equipped with a diversity processing circuit that selects the best reception condition from among multiple reception conditions. In the in-vehicle TV diversity device that sends out video and audio signals, The diversity processing circuit is applied to each of the video system and audio system of the received signal. It is constructed with a road. Further, an in-vehicle television diversity device according to another aspect of the invention includes: Equipped with a diversity processing circuit that selects the best reception condition from among multiple reception conditions. In the in-vehicle TV diversity device that sends out video and audio signals, For video, which converts high frequency signals into intermediate frequency signals corresponding to the video and audio systems. It is configured with a front end and an audio front end provided independently.

[0006]

[Effect]

In this invention, for example, the antenna with the best reception condition among multiple antennas is By providing diversity processing circuits for each of the video and audio systems. , and converts high frequency signals into intermediate frequency signals corresponding to these video and audio systems. By providing a video front end and an audio front end independently, Reduces audio switching noise caused by antenna switching for diversity are doing.

[0007]

【Example】

Next, this invention will be explained with reference to the drawings. Figure 1 shows the structure of an embodiment of the in-vehicle television diversity device according to this invention. It is a complete drawing. In Figure 1, components given the same symbols as in Figure 2 have the same functions as in Figure 1. It is a component that has The video diversity circuit 2 receives the received signals from the four antennas 1A to 1D. The received signal from the antenna with the best reception condition is then cut to the front end 4. output. The antenna switching circuit 3 selects two of the four antennas (2B and 2D in this example). The received signals from the antenna are received at the input terminals 31 and 32, and the signal from the antenna with good reception condition is received. is switched to the front end 4 and output.

[0008] The front end 4 converts the high frequency signal from the antenna into an intermediate frequency signal The circuit section includes a video front end 41 and an audio front end 42. The video front end 41 converts the signal from the antenna in the optimal reception state into a video. It is sent to the video detection circuit 7 as an intermediate frequency signal VIF. The video detection circuit 7 detects the video signal from the front end 41 and outputs the video signal, During the blanking period for instantaneous switching of the video diversity circuit 2. A corresponding switching video signal is output to the video diversity circuit 2. for this video The front end 41 is a dedicated front end configuration that emphasizes video band characteristics. 920KHz beat interference is eliminated. The audio front end 42 connects the input terminals 31 and 32 of the antenna switching circuit 3. It receives one of the input signals and converts it into a first audio intermediate frequency signal. This audio flow The first audio intermediate frequency signal SIF from the client end 42 is converted into a reference oscillation signal by the mixing circuit 5. It is mixed with the reference frequency signal from the device 6 and converted into a second audio intermediate frequency signal to produce sound. The signal is supplied to the voice detection circuit 8. This audio front end 42 has audio band characteristics. It uses a dedicated front end that emphasizes voice diversity. Buzz interference caused by images is eliminated. The audio detection circuit 8 detects the second audio intermediate frequency signal from the mixing circuit 5 and detects the audio signal. In addition to outputting the signal, the S meter level signal is also sent to the noise detection circuit 9. The noise detection circuit 9 receives the S meter level signal and detects multipath noise components. The amplifier is supplied to the antenna switching circuit 3 and output to the audio front end 42. Switch and select the tena output.

[0009] As mentioned above, when a car is running, the electric field strength of the video and the sound are not necessarily the same. Therefore, in this invention, video diversity and audio Diversity can be made independent to achieve the best reception conditions for each, and can be influenced by each other. This constitutes an unparalleled level of diversity. In the above embodiment, the front end section is a front end for video and a front end for audio. Although it is configured with a front end, the audio section may be separate, or a front end for audio may be used. It is possible to configure a 2-tuner diversity system using two ends. Yes, if you enable the front end to receive FM as well, you can download FM and TV audio. An diversity system is also configurable.

0010

[Effect of the idea]

As explained above, the in-vehicle TV diversity device according to this invention Diversity circuits for image signals and audio signals are configured independently, so the antenna This not only reduces switching noise when switching, but also reduces audio-only or video-only The best possible reception is possible during reception. Also compatible with both audio and video Because it has a front end with This also reduces interference (buzz) caused by video and audio. In addition, driving with a car Among other things, the best reception condition corresponding to changes in the electric field of audio and video can be switched. Yes, you can choose.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a vehicle-mounted television diversity device according to the present invention.

FIG. 2 is a configuration diagram of a conventional in-vehicle television diversity device.

[Explanation of symbols]

1 (1A~1D) Antenna 2 Diversity circuit for video 3 Antenna switching circuit 4 Front end 41 Video front end 42 Audio front end 5 Mixed circuit 6 Reference oscillator 7 Video detection circuit 8 Audio detection circuit 9 Noise detection circuit

Claims (3)

[Scope of utility model registration request] Claim 1. An in-vehicle television diversity device that has a diversity processing circuit that selects the best reception condition among a plurality of reception conditions and that transmits a video signal and an audio signal. An in-vehicle television diversity device, characterized in that the diversity processing circuit is provided in response to the above. 2. The in-vehicle television diversity according to claim 1, wherein the diversity processing circuit is a circuit that selects a received signal from an antenna with the best reception condition among outputs from a plurality of antennas. Device. 3. An in-vehicle television diversity device that includes a diversity processing circuit that selects the best reception condition from among a plurality of reception conditions, and that transmits a video signal and an audio signal, wherein An in-vehicle television diversity device characterized by independently providing a video front end and an audio front end for converting a high frequency signal into an intermediate frequency signal.