JPS61280128A - Diversity receiver for vehicle - Google Patents

Abstract

PURPOSE:To avoid generation of noise caused by wipering operation by providing a switching means changing over an antenna so as to select other antenna than an antenna installed on a glass face wiped at the operation of wiper and to receive an output signal of a wiper operation detection means. CONSTITUTION:When a wiper switch 13 is closed at a stable electric field region of a reception level, a periodic notch is generated in an induced voltage of a rear window heater and antenna 1 attended with the reciprocation of the rear wiper. In this case, attended with the closing of the switch 13, a switching transistor TR 1 of the 1st FM reception system 6 is turned on and the induced voltage of the rear heater and antenna 1 is brought forcibly into '0'. Thus, a rear pole antenna 2 is selected always and its induced voltage is inputted always to a high frequency amplifier circuit 4, the S/N is lowered slightly, the sound volume change of an on-vehicle speaker 5 is limited to a small value and the driver does not feel much feeling about noise.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a diversity receiving device equipped with a plurality of antennas on a vehicle, and in particular, at least one antenna is provided on a glass surface that is wiped with a wiper. Concerning improvements to what is being done.

(Prior Art) Generally, in this type of vehicle diversity receiving device, the vehicle is equipped with a plurality of antennas such as a ball antenna, a front windshield antenna, and a rear thermal 411 antenna. The reception level of the antennas is repeatedly tested and the antenna with the highest reception level at each point is selected over time in order to improve the reception performance (for example, Japanese Patent Laid-Open No. 5
7-188103, etc.).

(Problems to be Solved by the Invention) However, in the above-mentioned diversity receiving device, at least one antenna is of a type provided on the glass surface that is wiped by a wiper, such as a front windshield type or a rear hot wire type, etc. If it is of
During the wiping operation of the wiper, interference with radio wave reception occurs, which may cause periodic noise under certain conditions. In other words, in a stable m field where changes in the induced voltage of each antenna are small, if the induced voltage of a windshield antenna is always higher than that of a windshield antenna, the windshield antenna is always selected. A significant decrease in the induced voltage appears, and S
A disadvantage is that the /N ratio deteriorates and the volume significantly decreases periodically, which can be heard as periodic noise. In addition, in an unstable electric field region where the induced voltage changes of each antenna are large, windshield antennas and other antennas are alternately and frequently selected, so the noise generation window is less than one wiper wiping operation. Not so much.

The present invention has been made in view of the above, and although the S/N ratio is slightly low for antennas other than the antennas installed on the wiping glass when the wiper is wiping, the change in volume is small and the sense of noise is not so great. The purpose is to avoid the noise caused by the wiper wiping operation by forcibly switching the antenna selection to an antenna other than the above-mentioned antenna installed on the wiping glass surface when wiping the wiper. It's about doing.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a diversity receiving device for a vehicle in which at least one of a plurality of antennas is provided on a glass surface that is wiped by a wiper. , wiper operation detection means for detecting the operation of a wiper that wipes the glass surface on which the antenna is installed; and an antenna configured to receive an output signal from the wiper operation detection means and select an antenna other than the antenna installed on the wiped glass surface when the wiper is activated. This configuration includes a switching means for switching.

(Function) With the above configuration, in the present invention, when the wiper is wiping, although the induced voltage of the antenna installed on the wiping glass surface periodically decreases greatly due to the reception interference of the radio waves accompanying the wiping operation, the switching means Since an antenna other than the installed antenna with a small change in volume is selected, the generation of noise caused by the wiper wiping operation is reduced.

(Example) Embodiments of the present invention will be described below based on the drawings.

Figure 1 shows a diversity receiving device for FM broadcasting equipped with two antennas, 1 is a rear hot wire antenna installed on the rear windshield of the vehicle, and 2 is an antenna installed vertically at the rear of the vehicle. The V-heat wire antenna 1 is connected to a vehicle speaker 5 via a switching diode 3L15 and a high frequency amplification circuit 4 to form a first FM wave receiving system 6, and the rear ball antenna 2 is A second FM wave receiving system 8 is connected to the vehicle-mounted speaker 5 via the switching diode 7 and the high-frequency amplification circuit 4 described above.

In addition, Tr+ is a switching transistor that is provided in front of the switching diode 3 of the first FM wave receiving system 6, and forces the induced voltage of the rear hot wire antenna 1 to a value of '0'' when turned ON. It is installed in front of the switching diode 7 of the wave receiving system 8, and the O
This is a switching transistor that forcibly sets the induced voltage of the rear ball antenna 2 to the "0" value by N operation. Furthermore, 10 is an electric field level detector that determines the magnitude of the electric field level (induced voltage) between the rear hot wire antenna 1 and the rear ball antenna 2 based on the high frequency output from the high frequency amplifier circuit 4; Based on the electric field level signal from the electric field level detector 10, the two switching transistors T1°Trz are turned on alternately at appropriate times.
The antenna switching unit 11 is an antenna switching unit that performs rear heat II! When the electric field level of the dual-purpose antenna 1 is high, the switching transistor Tr2 of the second FM wave receiving system 8 is turned ON, thereby setting the induced voltage of the rear ball antenna 2 to the "OII value" and reducing the induced voltage of the rear hot-wire antenna 1. On the other hand, when the electric field level of the rear ball antenna 2 is high, the switching transistor Tr+ of the first FM wave receiving system 6 is turned on.
By doing this, the rear ball antenna 2 is selected so that the induced voltage of the rear hot wire antenna 2 is forcibly set to 0'' value, and the induced voltage of the rear ball antenna 2 is input to the high frequency amplifier circuit 4. be.

In addition, 12 is a motor for driving a rear wiper that wipes the glass surface (rear window glass surface) on which the rear heating wire antenna 1 is installed, and 13 is a wiper switch as a wiper operation detection means that operates the wiper motor 12 when opened. It is.

Then, the close signal of the wiper switch 13 is applied to the first wiper switch 13.
It can be input to the base of the switching transistor Tr+ of the FM wave receiving system 6, so when the wiper switch 13 is closed, that is, when the rear wiper is operated, the first F.
The switching transistor Tr+ of the M-wave receiving system 6 is controlled to be turned on by the closing signal of the wiper switch 13,
By forcibly setting the induced voltage of the rear hot wire antenna 1 to the 0'' value separately from the antenna switching unit 11,
A switching means 14 is configured to switch the antenna to select a rear ball antenna 2 other than the rear hot wire antenna 1 installed on the rear window glass surface.

Therefore, in the above embodiment, when the wiper switch 13 is opened, in the unstable electric field region of the reception level, the induced voltage of the rear heat antenna 111R and the induced voltage of the ball antenna 2 are changed, for example, as shown in FIG. Although the magnitude relationship between these changes over time, the antenna with the higher induced voltage is sequentially selected by the antenna switching #8 control of the antenna switching unit 11, and the image frequency amplifying circuit 4 Since the induced voltage indicated by the thick line in the figure is input to the , good receiving sensitivity can be obtained. Similarly, in the stable electric field region when the wiper switch 13 is activated simultaneously, if the induced voltage of the rear heating IIA antenna 1 is always higher than that of the rear heating IIA antenna 1, as shown in FIG. Since the dual-purpose antenna 1 is selected, good reception sensitivity can be obtained.

On the other hand, for example, when the wiper switch 13 is closed in the stable electric field region shown in FIG. However, there will be a significant decline in
In this case, when the wiper switch 13 is closed, the switching transistor Tr+ of the first FM wave receiving system 6 is turned ON, and the induced voltage of the rear hot wire antenna 1 is forcibly set to the ``0'' value. Therefore, the rear ball antenna 2 is always selected and its induced voltage is always input to the high frequency amplifier circuit 4.As a result, the S/N
Although the ratio decreases slightly, the sound jI* of the width-mounted speaker 5 is limited to a small level, and tower passengers do not feel much noise (
Become. Therefore, it is possible to avoid noise caused by the wiper wiping operation and improve reception performance.

Further, FIG. 4 shows a modification of the switching means 14, in which, instead of the switching transistor Tr+ configured as an electronic circuit in the above embodiment, it is configured as an electric circuit using a relay. That is, the antenna changeover switch 15 for selectively switching between the rear hot wire antenna 1 and the rear boat antenna 2 is controlled by the antenna changeover unit 11', and the antenna changeover switch 15 is forcibly operated during power supply. The switching means 14' is configured such that a switching relay 16 is provided on the rear ball antenna 2 side, and power is supplied to the relay 16 by closing the wiper switch 13. Therefore, similarly to the above embodiment, when the rear wiper is operated, the rear ball antenna 2 can be selected to improve reception performance.

In the above embodiment, a case was explained in which a plurality of antennas were configured with the rear heating wire antenna 1 and the V-ball antenna 2. However, in addition, a front windshield type antenna may be used instead of the rear heating wire antenna 1. Alternatively, a front pillar antenna may be used in place of the rear ball antenna 2, as long as at least one of the plurality of antennas is installed on the wiper wiped glass surface.

(Effects of the Invention) As explained above, according to the diversity receiving device for a vehicle of the present invention, an antenna other than the antenna installed on the wiper glass surface is selected during wiper wiping operation. This makes it possible to improve reception performance by avoiding significant changes in volume due to periodic sensitivity declines caused by wiping operations.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention, FIG. 1 is an electronic circuit diagram showing the overall schematic configuration, and FIGS. 2 and 3 show each antenna in an unstable electric field region and a stable electric field region, respectively. FIG. 4 is an electric circuit diagram showing a modification of the switching means. 1... Rear heating rod antenna, 2... Rear pole Trz... switching transistor, star. Figure 2 Figure 3

Claims (1)

[Claims] (1) In a vehicle diversity receiving device in which at least one of a plurality of antennas is provided on a glass surface that is wiped by a wiper, a wiper operation detection means that detects the operation of a wiper that wipes the glass surface where the antenna is installed; A diversity receiving device for a vehicle, comprising a switching means for receiving an output signal from the wiper operation detection means and switching an antenna to select an antenna other than the antenna installed on the wiping glass surface when the wiper is activated.