JPS6342583A - Automatic directivity switching antenna system - Google Patents

Abstract

PURPOSE:To automatically switch directivity to the optimum state, by constituting a system of respective means which detects a noise component in the horizontal synchronizing signal of a TV reception signal, and the presence/absence of a vertical synchronizing signal, and a means which switches the combination of antenna elements in a constant period. CONSTITUTION:A noise detection circuit 4, to which an H signal, an also an FBP are supplied from a receiver 3, generates a noise sampling pulse. A vartical synchronizing signal detection circuit 5 receives the vertical synchronizing signal (A), and a reset signal (B) being generated at the switching of an antenna from a control circuit 8, at a flip-flop 10, and its output signal (C) is supplied to a synthesis circuit 6 as a vertical synchronizing detection signal. The synthesis circuit 6 sets the output signal of the circuit 4 as a voltage in a state having a large quantity of noise compulsorily by the output signal of the circuit 5, when the vertical synchronizing signal is missed. And the output is supplied to a best point detection circuit 7. The best point circuit 7 outputs the output of the circuit 6 as it is in the first cycle of the antenna switching, and outputs the output to the circuit 7 in the second cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic directivity switching device for an indoor antenna used in a television receiver.

(Prior art) Generally, when receiving TV waves using an indoor antenna, the direction of the antenna element is changed or the shape is changed to obtain the best reception condition depending on the channel. This operation is difficult and extremely troublesome for viewers, as it is necessary to set it to an optimal state. Recently, indoor antennas that make this operation as simple as possible are equipped with multiple antenna elements 21 as shown in FIG. This reprint features a directional switching antenna that allows viewers to select the best condition while viewing the screen.

However, the troublesome operation of switching the rotary switch every time the channel is changed remains unresolved. Furthermore, in recent years, most television receivers have been used to switch channels using a remote control, so when combined with this indoor antenna, the operation of switching directivity has become even more troublesome. Furthermore, when a person approaches the antenna element in order to switch the directivity, the directivity changes, making it extremely difficult to obtain an optimal reception condition.

(Problems to be Solved by the Invention) In this way, in the conventional example, when selecting a channel on a television receiver, it is necessary to manually switch the directivity of the indoor antenna, which is a difficult and troublesome operation to obtain the optimal reception condition. There was a problem.

The present invention aims to solve this problem and provide an antenna device that can automatically switch the directivity to an optimal state.

(Means for Solving the Problems) The present invention provides means for detecting a noise component within a horizontal synchronization signal period in a composite video signal of a television receiver.

A means for detecting the presence or absence of a vertical synchronization signal, and a means for automatically switching between multiple combinations of antenna elements over a certain period of time, selecting and fixing a combination that provides the best directivity from the noise component and the vertical synchronization detection signal. It is composed of

(Function) The present invention can automatically switch the directivity of an indoor antenna, stabilize vertical synchronization, and select an image state with the smallest noise component.

(Example) FIG. 1 shows an overall block diagram of the present invention. The configuration and operation will be explained using FIG. 1. First, a plurality of antenna elements 1 are connected to a switching circuit 2 .

Here, the television signal received by the appropriately combined antenna elements is supplied as the antenna input for television reception +1!13. The composite video signal detected by the television receiver 3 is supplied to a noise detection circuit 4. Further, the vertical output signal of the vertical synchronization separation circuit in the television receiver is supplied to the vertical synchronization detection circuit 5. The output of the noise detection circuit 4 and the output of the vertical synchronization detection circuit 5 are supplied to a synthesis circuit 6,
The output of this synthesis circuit 6 is supplied to the best point detection circuit 7.

The output of this best point detection circuit 7 is supplied to a control circuit 8 that controls the switching circuit 2, and when the best point is detected, the switching circuit 2 is fixed. The noise detection circuit 4 is also supplied with a horizontal synchronizing signal and a flyback pulse from the television receiver 3, and generates a noise extraction pulse. Also,
A channel switching pulse is supplied from the television receiver 3 to the reset circuit 9 so that this automatic directivity switching control loop operates when the television receiver is turned on and when a channel is selected.

Next, the vertical synchronization detection circuit 5 and the synthesis circuit 6, which are the features of the present invention, will be explained. FIG. 2 shows a specific circuit of the vertical synchronization detection circuit 5, and FIG. 3 shows its operating waveforms.

A vertical synchronizing signal (a) is input to the set input terminal a of the SR flip-flop 10, and a reset signal (b) generated when switching the antenna is supplied from the control circuit 8 to the reset terminal a. On the other hand, the output signal (c) of this flip-flop 10 is supplied to the next stage synthesis circuit 6 as a vertical synchronization detection signal. The operation of the synthesis circuit 6 will be explained using the waveform diagram shown in FIG. The output signal of the noise detection circuit 4 (
d) by the output signal (c) of the vertical synchronization detection circuit 5,
In the state where the vertical synchronization signal is missing, the voltage is forced to be equal to the state in which the amount of noise is increased. The output is (E), which differs from the case without the vertical synchronization detection circuit 5 in that there is less noise [the dotted line in the waveform in FIG. 4 (E)].

This output is supplied to the best point detection circuit 7 at the subsequent stage.

The best point detection circuit 7 uses a peak hold circuit and a comparator to synthesize the signals in the first cycle of antenna switching.

The output voltage of the circuit 6 is held at its peak, and this peak voltage is supplied to one input of a comparator, and the output of the combining circuit 6 is supplied as is to the other input of the comparator. The best point can be detected from the output of the second cycle of the comparator outputs. This best point detection output is supplied to the control circuit 8, and antenna switching is stopped and fixed.

(Effects of the Invention) As described above, according to the present invention, the operation of an indoor antenna, which has conventionally been very troublesome and inconvenient, can be changed by automatically selecting a channel using a remote control and simultaneously selecting the combination that will give the best directivity. It is a very convenient and valuable device for viewers.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an automatic directivity switching antenna device according to an embodiment of the present invention, FIG. 2 is a diagram showing a specific circuit of the vertical synchronization detection circuit, and FIG. 3 is a diagram of the vertical synchronization detection circuit. FIG. 4 is a waveform diagram for explaining the operation of the combining circuit. FIG. 5 is an external view of a conventional indoor antenna. 1... Antenna element, 2... Switching circuit, 3...
・Television receiver, 4... Noise detection circuit, 5...
Vertical synchronization detection circuit, 6... Synthesis circuit, 7... Best point detection circuit, 8... Control circuit, 9... Reset circuit. Patent applicant Matsushita Electric Industrial Co., Ltd. Figure 2 Figure 3 (0) Re(!,) Penalty for the first cause --1-1111 "-111-
１－－－－－１F－－－－] [-Fig. 4 2) Lotus tun 11

Claims (1)

[Claims] A plurality of antenna elements, a switching means for switching a combination of these antenna elements and supplying a television signal received by the combination to a television receiver as an antenna input, and a horizontal synchronization signal for a composite video signal of the television receiver. noise detection means for extracting a period noise component; vertical synchronization detection means for detecting the presence or absence of a vertical synchronization signal of the television receiver; and signal synthesis means for synthesizing each output signal of the noise detection means and the vertical synchronization detection means. , a best point detecting means for detecting the best point of directivity by determining the magnitude of the output of the combining means, and a control means for controlling switching of the switching means based on the detection result of the best point detecting means; 1. An automatic directivity switching antenna device comprising reset means for restarting the operation of each of the means each time a channel is selected.