JPS5910604B2 - Receiving antenna device - Google Patents

Description

[Detailed Description of the Invention] This invention can receive the radio waves without any problem even when the direct wave and the reflected wave emitted by a wireless microphone, for example, arrive at almost the same level and are out of phase by 180 degrees. The present invention relates to a receiving antenna device configured as described above.

In general, radio waves emitted by a wireless microphone or the like reach an antenna of a receiver while generating various reflected waves as well as direct waves indoors.

In this case, when receiving with a dipole antenna, if the direct wave and the left reflected wave are at almost the same level and out of phase by 180 degrees, no voltage will be generated in this dipole antenna.
This is a so-called dead point, where reception is not possible.

In the case of dipole antennas, which are commonly used in the past, when the direct wave and the reflected wave arrive at almost the same level but with a 180 degree phase shift, as mentioned above, it is difficult to control the phase of the arriving signal. Since this is not done, the dead point described above is unavoidable.

In particular, a dead point that suddenly occurs in an electric field strength of 60 to 70 dB is a very bad condition in practice.

This problem cannot be solved by countermeasures on the receiver side because the reception signal disappears at the feeding point of the antenna.

Therefore, it is necessary to take measures on the antenna side.

Therefore, when a dead point occurs, the location of the antenna must be moved and the optimum position must be searched for, which requires a great deal of effort.

Also, countermeasures may be taken by setting up two antennas, but this also does not control the phase of the incoming signal, so
Dead points are inevitable.

In addition, space diversity may be achieved by installing two antennas in different positions and using two receivers, but this has the disadvantage of being expensive.

This invention was invented to solve such a problem, and the drawings will be explained in detail below. Fig. 1 is a schematic diagram thereof, and 1 and 1' are 1, predetermined length 0, and length 2. The antennas are six-inch antennas with a length of 0 and a length of 0,000 mm, and are arranged at predetermined intervals, that is, at intervals of i wavelengths.

The signal received by one of the dipole antennas 1 is
The signal is applied to the mixer 3 via a balloon 2 for impedance matching with the dipole antenna 1.

The signal received by the other dipole antenna 1' is applied to the mixer 3 via another balloon 2' and a phase converter 4 in sequence.

The mixer 3 mixes the above two signals and the extracted signal is guided to the antenna connector 5, which is connected to the antenna terminal of the receiver 6.

FIG. 2 shows a specific embodiment of this invention,
The main part of the phase converter 4 is a voltage variable capacitance diode D.
1, D2 and a coil L.

These voltage variable capacitance diodes D I and D 2 have
A predetermined DC voltage is applied from the receiver 6 through the antenna connector 5 and further through a resistor R for isolating high frequencies, and by continuously varying the DC voltage, the voltage variable capacitance diode D I , D 2 can change the phase of the signal received by the other dipole antenna 1'.

Incidentally, C1 and C2 in the phase converter 4 are capacitors for blocking the DC voltage, and 03 in the mixer 3 is also a capacitor for blocking the DC voltage.

Further, 7 is a feeder connecting the balloon 2' and the other dipole antenna 1'.

Although not shown, if the distance between one dipole antenna 1 and the balloon 2 is large, they are similarly connected via a feeder.

Next, to explain the operation of the present invention, as shown in FIG. If the phase B of the signal received at is shifted by 180 degrees as shown by the dash-dotted line, the output when these two signals are mixed at mixer 3 becomes zero, and the output becomes zero, which is the so-called dead point where reception is impossible. state.

In such a case, the DC voltage applied to the voltage variable capacitance diodes DI and D2 constituting the phase converter 4 can be continuously adjusted by adjusting a voltage regulator (not shown) provided on the receiver 6 side. By changing the phase, the phase of the phase converter 4 is controlled, and the phase B of the signal received by the other dipole antenna 1' is advanced by, for example, 90 degrees as shown by the dotted line B'. The phase shift between the two dipole antennas 1 and 1 becomes 90 degrees, and the dead point described above can be eliminated. Furthermore, by controlling the phase converter 4 as described above, one dipole antenna 1 and the other dipole antenna 1 can be By adjusting the two signals received at 1 and 2 so that they are close to the same phase, the signal voltage obtained at the antenna connector 5 can be further increased.

When actually controlling the phase of the phase converter 4, instead of controlling the phase while observing the phase relationship as shown in FIG. 3, the voltage adjustment device provided in the receiver is Just adjust it.

The voltage regulator may be a variable resistor or an automatic adjustment device that automatically adjusts the voltage regulator to increase the sensitivity when the sensitivity is low based on the detection of the receiving sensitivity of the receiver. Use as a means.

For example, as this automatic adjustment means, the voltage applied to the voltage variable capacitance diodes D I and D 2 is applied to the voltage variable capacitance diodes D I and D 2 based on the DC voltage obtained from an intermediate frequency amplifier or the like and which changes depending on the magnitude of sensitivity, such as automatic gain control. be made variable.

As explained above, in this invention, two antennas of a predetermined length are arranged at a predetermined interval, and a signal received by one antenna and a signal received by the other antenna are transmitted via a phase converter. In a receiver antenna device configured to mix the received signal with a mixer and guide it to the antenna connector, the applied voltage is adjusted according to the change in the level of the received signal guided to the previous receiver via the antenna connector. An automatic voltage regulator that continuously and automatically adjusts the voltage is provided in the receiver, and the voltage applied to the voltage variable capacitance diode constituting the phase converter is continuously and automatically controlled by the output signal of the automatic voltage regulator. By providing a receiving antenna device that controls the phase of the incoming signal from the other antenna by changing Even when the signals are received by the antenna with phases shifted by 180 degrees from each other, the voltage applied to the voltage variable capacitance diode constituting the phase converter is continuously and automatically changed. By performing phase control, it is possible to eliminate the occurrence of dead points, and furthermore, it is possible to adjust for the best sensitivity.

However, in the case of a radio wave emitter (broadcasting station) that constantly changes locations, such as a wireless microphone, it is preferable because the operator does not have to worry about constantly adjusting the voltage adjustment device. It has the advantage that it can be continuously changed and adjusted to provide the best reception sensitivity.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the present invention, FIG. 2 is a diagram showing a specific embodiment thereof, and FIG. 3 is a diagram showing the phase relationship of signals received by an antenna. ? ,1' ・・・Dipole antenna, 2,2'
... Balloon, 3... Mixer, 4...
... Phase converter, 5 ... Antenna connector, 6 ... Receiver, L ... Coil that constitutes the phase converter, D I , D 2 ...・・・Voltage variable capacitance diode, C, C2, C that constitutes the phase converter
3...Capacitor that blocks DC voltage.

Claims (1)

[Claims] 1 Two antennas of a predetermined length are placed at a predetermined interval, and a mixer mixes the signal received by one antenna and the signal received by the other antenna and passed through a phase converter. In the antenna device for a receiver configured to guide the received signal to the receiver via the antenna connector, the applied voltage is continuously and An automatic voltage adjustment device that automatically adjusts is provided in the receiver, and the voltage applied to the voltage variable capacitance diode constituting the phase converter is continuously and automatically changed by the output signal of the automatic voltage adjustment device. 1. A receiving antenna device, characterized in that the receiving antenna device controls the phase of an incoming signal from the other antenna.