JPS6342581A - Automatic directivity switching antenna system - Google Patents

Abstract

PURPOSE:To automatically switch directivity to the optimum state, by detecting the presence/ absence of a noise component, and a vertical synchronizing signal in the horizontal synchronizing signal period of a TV reception signal, and switching an antenna element synchronizing with the vertical synchronizing signal, based on the above stated two detection signals. CONSTITUTION:A noise detection circuit 4 detects the noise component in the horizontal synchronizing signal period, and a vertical synchronizing signal detection circuit 5 detects the presence/absence of the vertical synchronizing signal. A synthesis circuit 6 supplies the synthesized output of those detected outputs to the best point detection circuit 7. The output of the circuit 7 is supplied to a control circuit 8 which controls a switching circuit 2, and when the best point is detected, the circuit 2 is fixed. To the circuit 4, the horizontal synchronizing signal and also a flyback pulse are supplied, and a noise sampling pulse is generated. A channel switching pulse is supplied to a reset circuit 9 so that the control loop can be operated at the time of applying a power source, and the time of selecting a channel. A clock generation circuit 10 inserts the output of an oscillator 12 when no vertical synchronizing signal exists, and drives the circuit 8 with a vertical cycle. The synthesis circuit 6 sets the the output signal of the circuit 4 as the signal having a large quantity of noise compulsorily by the output signal of the circuit 5, when the vertical synchronizing signal is missed.

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 television waves using an indoor antenna, the direction of the antenna element is changed or the shape of the antenna element is changed in order to obtain the optimum 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. Directivity switching antennas are available on the market that allow viewers to select the best condition while viewing the image.

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, and a means for detecting a noise component within a horizontal synchronization signal period in a composite video signal of a television receiver;
means for detecting the presence or absence of signal, means for generating a clock synchronized with the vertical synchronization signal, and switching the combination of antenna elements driven using this clock to obtain the best directivity from the noise component and the vertical synchronization detection signal. and means for selecting and fixing.

(Function) The present invention can automatically switch the directivity of an indoor antenna, stabilize vertical synchronization, and select an image state in which noise components are minimized. Furthermore, since the directivity is switched in synchronization with the vertical synchronization signal, selection can be made stably and in a short time.

(Embodiment) 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, television signals received by the appropriately combined antenna elements are supplied as antenna elements of the television receiver 3. 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 circuit 5 are supplied to a synthesis circuit 6, and 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,
This control loop for automatic directivity switching is based on the television receiver 3.
A channel switching pulse is supplied from the television receiver 3 to the reset circuit 9 so that it operates when the power is turned on and when a channel is selected.

Next, the clock generator 10 that drives the control circuit 8, which is a feature of the present invention, will be explained. FIG. 2 shows a specific circuit of the clock generator 10, and FIG. 3 shows waveforms for explaining its operation. Vertical synchronization signal (a) is connected to terminal a
and are supplied to one input of AND circuits 11 and 13, respectively. The flyback pulse is input to the clock of the oscillator 12 via a terminal. This oscillator 12 counts 262 clocks and outputs an output signal (d). This output signal (d) is supplied to the other input of the AND circuit 13, which outputs an output signal (e). Further, the channel switching signal (c) is input to the terminal C, and is supplied to the other input of the AND circuit 11, and the output of the AND circuit 11 is supplied to the reset input terminal of the oscillator 12.

In other words, if there is no vertical synchronization signal, the output of the oscillator 12 is inserted, and a clock is always output with a vertical period.

Next, the vertical synchronization detection circuit 5 and the synthesis circuit 6 will be explained. Figure 4 shows the specific circuit of the vertical synchronization detection circuit, and Figure 5 shows the specific circuit of the vertical synchronization detection circuit.
The operating waveforms are shown in the figure.

A vertical synchronizing signal (a) is supplied to the set input terminal d of the RS flip-flop 14, and a reset signal (g) synchronized with antenna switching is supplied from the control circuit 8 to the reset input terminal e. On the other hand, the output signal (H) of this RS flip-flop 14 is supplied to the combining circuit 6. The operation of the synthesis circuit 6 will be explained using the waveform diagram shown in FIG. When the vertical synchronization signal is missing, the output signal (S) of the noise detection circuit 4 is forcibly made into a signal equal to the state in which the amount of noise is increased by the output signal (H) of the vertical synchronization detection circuit 5. . As shown in the waveform of this output signal (nu), the best point is different from the case without the vertical synchronization detection circuit 5 [dotted line part in Figure 6 (nu)]. The signal is supplied to the best point detection circuit 7. The best point detection circuit 7 uses a peak hold circuit and a comparator to peak-hold the output voltage of the combining circuit 6 in the first cycle of antenna switching, supplies this peak voltage to one input of the comparator, and supplies the peak voltage to one input of the comparator. The output voltage of the combining circuit 6 is directly supplied to the other input. The best point can be detected from the second cycle output of the comparator. 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 done by selecting a channel using a remote control, for example, and at the same time stably achieving the best orientation in a short time. This is a very convenient and valuable device for viewers because the combinations that give them the best possible sex are automatically selected.

[Brief explanation of drawings]

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 specific circuit diagram of a clock generator, and FIG. 3 is a diagram for explaining the operation of the clock generator. 4 is a partial circuit diagram of the vertical synchronization detection circuit, FIG. 5 is a waveform diagram for explaining the operation of the vertical synchronization detection circuit, and FIG. 6 is a waveform diagram for explaining the operation of the synthesis circuit. The waveform diagram, FIG. 7, is an external view of a conventional indoor antenna. 1... Antenna element, 2... Switching circuit, :3.
...TV receiver, 4...Noise detection circuit, 5...
- Vertical synchronization detection circuit, 6... Synthesis circuit, 7... Best point detection circuit, 8... Control circuit, 9... Reset circuit, 10... Clock generator. Figure 1 Figure 2 Figure 3 Figure 4 Figure I4 Figure 5 Figure 6

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 detection means for detecting the best point of directivity by determining the magnitude of the output of the synthesis means, a clock generation means for generating a signal synchronized with the vertical synchronization signal, and a drive unit driven by the signal of the clock generation means. and a control means for controlling switching of the switching means based on the detection result of the best point detection means, and a reset means for restarting the operation of each of the means each time a channel is selected. Directivity automatic switching antenna device.