JPS5850041B2 - Antenna directivity adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna for receiving various radio waves, such as UHF and VHF television waves, and more particularly to a directional characteristic adjustment device for the antenna, which sharply catches target radio waves and eliminates interference waves. It is possible to greatly reduce the influence, and even if the interference waves come from different directions, the directivity characteristics can be adjusted accordingly, and furthermore, even if such adjustment can be made from hand, it is a dedicated device. An object of the present invention is to provide an antenna directional characteristic adjustment device that can eliminate the need for a control circuit.

The drawings showing the embodiments of the present application will be described below.

In FIG. 1, a mast 3 is erected on the roof of a house 1 via a roof horse 2, and a support arm 4 is fixed to the upper end of the mast 3 at both ends of a C support arm 4. Antennas 5 and 6 are fixed in parallel to each other, respectively.

Connection cables 7 and 8 are connected to the power feeding parts of the husband antennas 5 and 6, and the other ends of each are connected to an operating part 9 in an adjustment device fixed to the mast 3.

10 is a feeder line connected to the operating section 9, which connects the antennas 5 and 6;
It is designed to draw signals from the inside into the building.

Incidentally, as the connection cables 7.8 and the power supply line 10, for example, coaxial cables are used.

Reference numeral 11 indicates a control unit in the adjustment device connected to the indoor end of the power supply line 10, and reference numeral 12 indicates a television receiver, which is exemplified as a receiver connected to the control unit 11.

Next, in FIG. 2 showing the circuit of the operating section 9, 15°16
are input terminals to which antennas 5 and 6 are connected, respectively.

1T is a phase shifter, which is configured to shift the phase of a received signal from the antenna in accordance with a control voltage signal applied to the phase shifter.

Reference numeral 18 denotes an attenuator, which is configured to attenuate the received signal from the antenna in accordance with a control current signal applied to the attenuator.

19 is a well-known combiner, and 20 is a low frequency blocking circuit, which is configured to allow the composite signal from the combiner 19 to pass, but to block signals of lower frequencies.

Reference numeral 21 denotes a connection terminal to which the antenna side end of the feeder line 10 is connected.

Reference numeral 22 denotes a high frequency blocking circuit, which is configured to block passage of high frequency signals received by the antenna, but allow signals of lower frequencies to pass.

Reference numeral 23 denotes a frequency-to-voltage converter, which is configured so that the output voltage changes according to the frequency of the input signal to itself, and whose output terminal is connected to the output terminal where the output signal is applied to the phase shifter 17 as a control voltage signal. It is connected to this so that

24 is a voltage-to-current converter, which is composed of a rectifier circuit 25 and a DC bridge 26, and this converter 24 is configured so that its output current changes according to the voltage of the input signal to itself; Its output terminal connects its output current to attenuator 1
8 so that it can be sent as a control current signal.

Next, in FIG. 3 showing the circuit of the control unit 11, reference numeral 30 denotes a connection terminal to which the receiver side end (indoor end) of the feeder line 10 is connected.

31 is a low frequency blocking circuit, which is similar to the low frequency blocking circuit 20 described above.

32 is an output terminal to which the television receiver 12 is connected.

33 indicates an oscillation circuit with variable oscillation frequency, and 34 indicates its regulator.

The oscillation waveform of the oscillation circuit 33 may be a rectangular wave, a sine wave, or any other arbitrary waveform, and its frequency is, for example, 1000 to 10000 Hz, but other frequencies may also be used.

Reference numeral 35 denotes an amplitude voltage adjustment circuit, which is configured to adjust the amplitude voltage of the oscillation output from the oscillation circuit 33, and 36 represents the adjuster.

Reference numeral 37 denotes a high frequency blocking circuit, which is similar to the high frequency blocking circuit 22 described above.

Reference numeral 38 denotes a power supply circuit which supplies power to the oscillation circuit 33 and the amplitude voltage adjustment circuit 35.

In the configuration described above, the reception signals received by the antennas 5 and 6 are input to the operating section 9 via the connection cables 7.8, respectively.

In the operating section 9, the signal from the antenna 5 is passed through a phase shifter 17.
The softening is shifted by , and the output reaches the combiner 19 .

On the other hand, the signal from antenna 6 is attenuated by attenuator 18 and reaches combiner 19 .

These signals are combined in a combiner 19 and sent as one signal to a connection terminal 21 via a low frequency blocking circuit 20.

The power is drawn indoors from the connection terminal 21 via the power supply line 10 and reaches the connection terminal 30 in the control unit 11 .

In the control unit 11, the signal passes through a low frequency blocking circuit 31, reaches an output terminal 32, and is further input to the television receiver 12.

Next, the operation of the above adjustment device will be explained.

The control signal whose frequency is selected in the oscillation circuit 33 in the control section 11 and whose amplitude voltage is selected in the amplitude voltage adjustment circuit 35 is transmitted to the high frequency blocking circuit 37 and the connection terminal 3.
0 to the feeder line 10.

This control signal reaches the connection terminal 21 in the operating section 9 via the power supply line 10.

In the operating section 9, this signal is passed through a high frequency blocking circuit 22 to a frequency to voltage conversion circuit 23 and a voltage to current converter 24.
is input.

In the frequency-to-voltage converter 23, the frequency of the control signal is converted into a control voltage signal, which is input to the phase shifter 17.

In the phase shifter 17, the phase of the received signal from the antenna is shifted according to the control voltage signal.

On the other hand, in the voltage-to-current converter 24, the signal is first rectified in a rectifier circuit 25, and then further rectified by a DC bridge 26.
is input.

In the DC bridge 26, the amount and direction of the current applied to the attenuator 18 are adjusted according to the voltage of the signal.

Therefore, in the attenuator 18, the amount of attenuation of the received signal from the antenna is changed depending on the amount and direction of the current.

Next, the operation of removing interference waves (ghosts) using the above adjustment device will be explained.

First, while watching the screen of the television receiver 12, the adjuster 34 in the oscillation circuit 33 is adjusted so that the ghost is minimized.

Next, the adjustment work is completed by adjusting the regulator 36 in the amplitude voltage adjustment circuit 35 so that the ghost becomes even smaller.

Next, how the directivity characteristics of the antenna change due to the above adjustment will be explained based on FIG. 4.

In this case, it is assumed that both antennas 5 and 6 have the same characteristics.

When the signal from antenna 5 passes through phase shifter 17, this signal creates a phase difference of δ with respect to antenna 6, resulting in a certain transmission loss.

If the amount of attenuation of the attenuator 18 is adjusted so that the level at which the signal from the antenna 6 is attenuated is equal to this passing loss,
The synthesizer 19 synthesizes signals having equal level amounts and a phase difference of δ.

The directional characteristic D(θ) of the synthesized array antenna is DO(
θ) is the directivity characteristic of antenna 5 and antenna 6 alone, λ is the wavelength of the received radio wave, and d is the antenna spacing converted to wavelength.

In order to eliminate ghost waves arriving from the direction of θ, it is sufficient to set D(θ)=O.

That is, from the equation 2π (3), the phase difference δ between antennas 5 and 6 is −Tds
When adjusted to inθ, a null point of the combined directivity of the antennas 5 and 6 is created in the θ direction, and ghost radio waves from this direction are eliminated.

Note that even if the θ direction is the same, if the receiving wavelength is different, the value of d will change relatively, and the condition of δ = −〒ds in θ will change, so
Depending on the reception wavelength, δ is adjusted by the phase shifter 17 so that the above conditions are satisfied.

Also, depending on the passing loss of the phase shifter 17 at that time, the attenuator 21
Adjust the amount of attenuation.

Next, FIG. 5, which shows an example of the circuit of the phase shifter 17 and the frequency-to-voltage converter 23, will be described.

41 is an input terminal connected to the terminal 15, and 42 is a DC blocking capacitor that blocks the DC from the converter 23 from going to the antenna side.

43... are phase shift elements, and coils L1. L2 and a variable capacitance diode D6, and is configured such that the amount of phase shift changes when the voltage applied to the variable capacitance diode D6 changes.

Note that the number of phase shift elements 43 used is such that a necessary amount of phase shift can be obtained depending on the frequency used.

44 is a capacitor similar to the capacitor 42, and 45 is an output end connected to the combiner 19.

Note that any other arbitrary element can be used as the phase shift element 43 as long as the amount of phase shift changes depending on the magnitude of the voltage applied to the phase shift element 43.

Next, in the frequency-to-voltage converter 23, this converter is constructed by connecting a constant voltage diode, a rectifier diode, a capacitor, and a resistor, each indicated by a symbol, as shown in the figure, and its input terminal 47 is High frequency blocking circuit 22
is configured to connect to.

A high frequency blocking circuit 48 is provided to block high frequency signals from flowing into the converter 23 from the phase shifter 17.

In such a circuit, the amplitude voltage of the signal applied to the input terminal 47 is determined by the Zener diode D.

As shown in FIGS. 6a and 6c, a rectangular wave AC voltage of a constant EA volt is applied to the two points.

When both capacitors C1 and C2 have a charge of O, when this rectangular AC voltage is applied for one cycle, the voltage at the point is as follows: 2 E01= EA (4)
C1+C2 Voltage E across capacitor C1 in the next cycle.

2 is E in equation (4).

Approximately twice the E for 1 voltage. 1, and then repeat in sequence to reach the 6th
Figures b and d: As shown, the shame potential rises in a stepwise manner.

However, since it is discharged by the resistor R0 in parallel with the capacitor C1, Eo is in an equilibrium state as shown in the figure.

This equilibrium state is determined by the rate of charge accumulation, that is, the frequency of the rectangular AC voltage, and the time constant R1 (C1+C2).

Since R1, C1, and C2 are constant, Eo becomes proportional to frequency.

That is, as shown in FIG. 6, if the frequency of EA increases, E.

The potential of will increase. Note that this converter 23 is as follows:
Any other device may be used as long as the output voltage changes depending on the frequency of the input signal as described above.

In this way, in the frequency-to-voltage converter 23, control voltage signals of different voltages are created according to the frequency of the input signal, and in the phase shifter 17, the phase of the received signal is created according to the control voltage signal. is shifted.

Next, FIG. 7 showing an example of the circuit of the attenuator 18, the rectifier circuit 25, and the DC bridge 26 will be described.

These circuits are constructed by connecting the members indicated by the symbols as shown in the figure, and the input terminal 5
0 to the input terminal 16, the output terminal 51 to the synthesizer 19, and the control signal input terminal 52 to the high frequency blocking circuit 22.

Furthermore, diode D3. A PIN diode is used as D4.

Further, L3 to L6 are coils for blocking passage of high frequency waves.

In such a circuit, when a rectangular wave AC voltage enters the input terminal 52, it is rectified by the diode D, smoothed by the capacitor C7, and applied to the point A in the DC bridge 26.

In the DC bridge 26, the potentials at the point and point C rise and fall relative to each other depending on the applied voltage.

Therefore, the amount and direction of the DC current applied from the DC bridge 26 to the attenuator 18 change, and the attenuator 1
8, the amount of attenuation changes in accordance with the change.

As the attenuator 18, the DC bridge 26, and the rectifier circuit 25, other than those shown in the drawings, any circuit can be used as long as it operates as described above.

As described above, the present invention has the feature that when attempting to receive radio waves, the target radio waves can be caught sharply due to the sharp directional characteristics, and stable reception can be achieved without interference.

Furthermore, since the direction of such sharp directional characteristics can be changed, there is an advantage that even when interference waves come from different directions, adjustments can be made to minimize the interference and enable good reception.

Furthermore, such adjustments can be made at hand, far away from the antenna, for example while watching a TV screen, and have the advantage of being extremely simple and highly safe without the need to climb onto the roof. There is.

Furthermore, even if the device can be operated by hand as described above, the phase is changed depending on the frequency of the signal sent from the hand, and the attenuation amount is changed depending on the voltage of the signal, so these signals cannot be easily controlled. It can be sent superimposed with the received TV signal, thereby eliminating the need for a special electrical line to change the directivity, and eliminating the need for a single feeder line, which is essential for bringing the received signal indoors. There are features that can be used.

This not only makes installation more economical, but also reduces maintenance and inspection costs during long-term use.

[Brief explanation of drawings]

The drawings show an embodiment of the present application. Fig. 1 is a schematic diagram showing the installation state of the antenna and the antenna directional characteristic adjustment device, Fig. 2 is a block diagram of the operating section, and Fig. 3 is a block diagram of the control section. Fig. 4 is a schematic plan view for explaining directivity, Fig. 5 is a circuit diagram showing an example of a phase shifter and a frequency-to-voltage converter, and Fig. 6 shows waveforms at each point in the converter. FIG. 7 is a circuit diagram showing an example of an attenuator and a voltage-to-current converter. 5.6...Antenna, 17...Phase shifter, 18...Attenuator, 19...Synthesizer,
10... Power supply line, 23... Frequency to voltage converter, 24... Voltage to current converter, 33.
...Oscillation circuit, 35...Amplitude voltage adjustment circuit.

Claims (1)

[Claims] 1 One of the two antennas installed parallel to each other outdoors is equipped with a phase shifter that can shift the phase of the received signal from the antenna according to the control voltage signal applied to the antenna itself. and the other antenna,
An attenuator capable of attenuating the received signal from the antenna in accordance with a control current signal sent to the antenna itself is connected, and the outputs of the phase shifter and attenuator are connected to a combiner, and the outputs of the combiner Connect the antenna side end of the feeder line that draws the above received signal towards the indoor receiver to the output,
Furthermore, at the antenna side end of the feed line, there is a frequency-to-voltage converter that changes the output voltage according to the frequency of the input signal to itself, and a frequency-to-voltage converter that changes the output current according to the voltage of the input signal to itself. A voltage-to-current converter is connected, the output of the frequency-to-voltage converter is connected to the phase shifter, and the output of the voltage-to-current converter is connected to the attenuator, while the output of the frequency-to-voltage converter is connected to the attenuator. At the end of the wire on the receiver side, there is an oscillation circuit with a variable oscillation frequency and an amplitude circuit that adjusts the amplitude voltage of the signal from the oscillation circuit and sends the adjusted signal to the feeder line. An antenna directional characteristic adjustment device, characterized in that a voltage adjustment circuit is connected.