JPS5870642A - Receiver for car - Google Patents

Abstract

PURPOSE:To prevent the reception characteristics from being changed in a horizontal or a vertical polarization areas, by providing an antenna having lateral and longitudinal elements at a front glass of a car. CONSTITUTION:A front glass 1 of a car is provided with the 1st antenna 2 of folded dipole type, T-shaped with horizontal elements along the upper side, and the 2nd antenna 3 in parallel-wire shape having vertical elements along the sides. The antenna which can obtain an excellent reception signal is switched and selected with a selecting swith circuit 11. Figure shows a means which automatically switches and selects the antennas with a reception level detection signal and a multi-path distortion detection signal (to detect distortion of a stereo pilot signal of 19kHz).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiving device using a glass antenna for radio reception, etc. provided in a window lf2 of a car, and is particularly suitable for use in a diversity receiving system.

When a moving car receives radio waves such as FM broadcasts, periodic phasing occurs due to fluctuations in the field strength of the received radio waves in the direction of travel, and Martino matrix distortion occurs due to movement of the receiving point. The received sound quality is likely to deteriorate due to fluctuations and other causes, and in particular, the received sound may become "dry" and cut off in short periods, making it difficult to recognize the received content.

The present invention provides a receiving system that can solve this problem, and particularly aims to prevent the receiving characteristics from changing between horizontally polarized areas and vertically polarized areas.

Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, a pair of antenna wires are enclosed in or attached to the front window glass of an automobile, and city reception is performed using these pair of antenna wires. One antenna line has at least lateral (horizontal) antenna elements, and the other antenna line has at least longitudinal (vertical) antenna elements. Although the windshield of an automobile generally has an inclination angle, in this specification, an element arranged vertically in the front view of the windowpane is referred to as a vertical or vertical antenna element.

FIG. 1 is a front view and an electric circuit diagram of a windshield of an automobile showing a first embodiment of the present invention.

In Figure 1, the water along the upper side of the windshield (1); the first antenna (2) shaped like a T-shaped folded dial; A second parallel antenna (3) with vertical elements along the sides is provided. Copper wire or the like is used as the wire material constituting each antenna (2) (3), and multiple glass plates are laminated with an adhesive interlayer film, and the pattern shown in Figure 1 is formed on the interlayer film of nine laminated glasses. It is wired with.

In the case of windshields, the wiring position and number of antenna wires are regulated so that the antenna wires do not interfere with the driver's ascent. For example, in the Automobile Manufacturers Association regulations or CHP regulations, as shown in the front view of the windshield in Figure 2, 10 rows from each side and 1001 areas (4) on both sides of the center line.
It is possible to wire at most two wires only in the shaded area (5th area), and there is a regulation stating that antenna elements must not be placed in the area.The antenna pattern in Figure 1 ←This regulation is satisfied. Also, point 4 on the gi diagram!
As shown in (3)', a parallel linear second antenna (3) may be arranged near the other side of the windshield.

The lead wire of the antenna wire to the receiver is connected by forming a notch (6) in one glass plate of the laminated glass and using a terminal fitting in that part.

The outputs of the first and second antennas (2) (3) are connected to the preamp f (9) H via lead wires (7) (8), respectively.
Further, one of the better received signals is selected by the selection switch circuit (b) in order to perform map-page reception, and is supplied to the FM receiver. Also, the output of the longer first antenna (2) is the lead ii! (7) to the Noriamp (6) and further supplied to the AM receiver.

The leads @ (7) (a) are unbalanced coaxial lines connected to the respective terminals of the antennas (2) and (3). Note that in order to increase the level of AM reception output, the first
Take out two output terminals of the 0 antenna (2) separately, short-circuit them with a high impedance inductance in the FM frequency range, take out from the middle tap of this inductance, and connect it to the preamplifier via another lead wire as the AM reception output. (2) K may be derived.

FIG. 6 is a block circuit diagram of the FM receiver used in this embodiment. In FIG. 3, the first antenna (2
) or the received signal received by the second antenna (3) is selected by the changeover switch circuit (b) also shown in FIG. 1, and is supplied to the 70-point end and the IF open circuit c). The received signal that has undergone tuning amplification, intermediate frequency conversion, and FN1 detection at this 70-tone end and IF open circuit is
The signal is supplied to the multi-bleph sensor (2) via the high-frequency cut control filter (2) and the noise plunker, where it is stereo demodulated and output from the R channel and L channel output terminals to the audio power amplification section. Note that a control signal C such as an automatic stereo/monaural switching signal is applied to the multi-brephuser from the IF circuit.

In the front end and IF open circuit c), the distance between stations is
1 In order to interfere with noise, the reception level is detected (level detection of IF output or detection output), and when the reception level drops to a certain level, the detection output is miniaturized. . This reception signal level detection signal a is given to the mute drive circuit (2) in the IP circuit (2) and is also sent to the automatic level setting circuit (2). This automatic level setting circuit ■ is a switch circuit (
B) The function of changing the threshold of the switching input level according to the switching frequency is IQ, and when the level is below this threshold, a detection signal S is generated. This detection signal is sent to the antenna switching control circuit), where a switching I# signal d is formed in synchronization with the approximately 100 KHz clock of the clock generator output. This switching node 4xd is given to the trigger input of the 'r board fritz f70gu e intuition,
As a result, the output (Q, ζ) at the time of 7-lip float c1
is reversed. .

The Q output and the 4-output of the 7 rig 70 tsugu e1 are used as switching control signals of the switch circuit (b), for example, the first
When the received signal level of antenna (2) drops below the set reference value, the fritsuno 70 knob is reversed and its Q-
The output becomes a low level, and the fourth output becomes a high level and is switched to the antenna output of the second antenna (3). The Q output of the Fritsuno 70 Tube C11) is also given to the automatic level setting circuit (2), and this - circuit is connected to the second antenna (
3) The operation mode is switched to detect a decrease in the reception level. Therefore, next time the reception level of the second antenna (3) drops below the set reference level, the automatic level setting circuit detects this, and based on the detection output, the antenna switching control circuit d is generated again, and this pulse d inverts the 7-lip 70-tube clη. Therefore, the switch circuit (b) is switched to the first antenna (2) side.

As a result, diversity reception is performed in which the antenna output is always switched to a higher antenna output than the set level of the reception level.

Furthermore, in the embodiment shown in FIG. 6, variations in multi-arm distortion are detected and reception can be performed by switching to the antenna output with less distortion. That is, the output of the front end and IF circuit (c) is also supplied to a 19 KHz pantone filter), where a stereo pilot signal is extracted1, and this pilot signal is fed to a level fluctuation detection circuit (c). It will be done. If the received signal is distorted by the multipath signal, the lever and pilot signals are also distorted, so by detecting the level fluctuation (variation in the distortion component), it is possible to detect the increase or decrease in multipath distortion due to the movement of the receiving point. I can do it.

When the multipath distortion increases by more than a certain amount, the high-frequency cut control filter (c) is activated by the output e of the level fluctuation detection circuit (to), and the high-frequency distortion component of the detection output is cut and sent to the multiplexer). Given.

At the same time, the output e of the level fluctuation detection circuit (to) is also sent to the antenna switching control circuit ■, and the switching pulse d is formed as described above, and is sent to the output of the other antenna as in the case of reception level fluctuation. This results in a received signal with less or less multipath distortion. Note that the antenna switching control circuit (2) forms a switching pulse d when either one of the outputs (i) and (e) of the automatic level setting circuit (2) and the level fluctuation detection circuit (to) is input. That is, the switching pulse d is created by the OR logic of the signal S and e.

In addition, the front end and IF circuit (c)
The received level detection signal a obtained from the antenna switching control circuit is given as an operation prohibition signal to the antenna switching control circuit), thereby causing switching between 1 and 1? The formation of rus d is prohibited.

According to the embodiments shown in FIGS. 1 and 3, even if periodic fluctuations in facing or multipath distortion occur due to the movement of the receiving point when the car is running, the two antennas (2) (
3) Due to the difference in the placement position, the fluctuation status of the reception level of each antenna is different, so the reception output of the better one is selected and the space diversity reception is used to minimize the influence on the reception sound quality. It can be carried out.

Furthermore, since one of the first and second antennas (2) (3) has at least a horizontal antenna element, and the other has at least a vertical antenna element,
Polarization diversity reception can be performed by utilizing the fact that the 72-song situation is different in the polarization plane of the received radio wave. In particular, there are areas where horizontal polarization is used and areas where vertical polarization is used, so polarization diapacity reception is extremely effective when the reception point moves, such as in a car. . In the embodiment shown in FIG. 1, the first antenna (
2) The rt antenna is mainly suitable for receiving horizontally polarized waves, and the second antenna is suitable for receiving vertically polarized waves.

Next, FIGS. 4 to 16 are plan views of the same windshield as in FIG. 1, showing various modifications of the antenna pattern that can perform the wireless reception of this embodiment.

Figure 4 shows the first antenna (2) constructed by bending a single wire.
second antenna (3) (or G3)' parallel to
) in combination with 69, Figure 5 shows a first semi-folded dipole-like antenna (2) provided along the upper side of the windshield (1) and a second parallel bilinear antenna (3). (or (1)”).In addition, the fifth
One semi-folded dipole-like antenna (2) in the figure
Although it can be installed along the lower edge of the windshield (1), it is more advantageous to place it along the upper edge in terms of electric field strength. and a parallel bilinear second antenna (3) (or (3)); Fig. 7 is a combination of an open-loop antenna (2) and a parallel bilinear antenna; Fig. 8 is a combination of an open-loop antenna (2) and a parallel bilinear antenna; A dipole-like first antenna (2) and a parallel bilinear second antenna (
3). Figure 9 shows the first antenna (2) and the windshield (1
), the combination with a parallel two-linear second antenna (3) arranged on the center line of Fig. 11 shows the combination of the first antenna (2) of Guypole and the second parallel two-linear antenna in the center.
This is a combination with antenna (3). Furthermore, Figures 1 to 1
In Figure 1, each of the parallel two-linear antennas may be a perpendicular two-element single-element antenna, but the two-linear antenna has a better receiving frequency band.

Fig. 12 shows a U-shaped first antenna (combined with a bilinear second antenna (3) in 2T'F rows) along both sides and the bottom of the windshield (1), Fig. 13 is 2
Figure 14 shows a combination of two L-shaped first and second antennas (2) (3).
) and an L-shaped second antenna (3), Figure 15 shows the L-shaped first and second antennas (2).
(3) arranged symmetrically with respect to the center line, No. 16
Figure Fi, first and second antennas (2) in open loop form (
3) are arranged symmetrically with respect to the center line.

Note that each antenna in Figs. 5, 6, and 8 to 11 (
2) and (3) have insufficient element length for AM waves,
The AM reception level may drop, so the antenna (
2) It is preferable to couple the terminals in (3) with an inductance element that has low impedance for AM waves and high impedance for FM waves, and extracts the AM reception signal from the intermediate tag of this inductance element.

In the modified examples of the patterns shown in FIGS. 4 to 16 above, Hiro,
As in FIG. 1, one of the antennas has at least a horizontal antenna element, and the other has at least a vertical antenna element, so space diversity reception and polarization diversity reception are possible. Note that the windshield of a car does not have the anti-shock striations like the rear glass, so we compared antenna elements that are mainly horizontal elements and antenna elements that are mainly vertical elements within the constraints shown in Figure 2. Can be freely combined.

In addition, in each of the modified/parallel examples shown in Figs. 5, 6, and 8 to 11, the second antenna (3) has a large diameter in the longitudinal direction of the vehicle as shown in the characteristic diagram in Fig. 17. Shows directional characteristics (solid line) with delag. On the other hand, the horizontal single element antenna (Figs. 6 and 10), semi-folded antenna (Figs. 5 and 89), and held antenna used as the first antenna (2) in these examples The antennas (Figs. 8, 9, and 11) exhibit similar directivity characteristics with delag in the front and rear directions in free space, but when placed along the mesoie of the car as shown in the figure, ,
Under the influence of the body, it may exhibit directivity in the front/rear direction of the car, as shown by the dotted line in Figure 17, or it may be almost omnidirectional (
In the semi-folded case). Therefore, the first and second antennas having these characteristics are switched to perform high-performance reception: 1. In particular, it is possible to obtain received signals without any directional characteristic delay.

Although the present invention has been described above based on examples, various modifications can be made within the scope of the technical idea of the present invention.

In particular, with regard to the antenna pattern, it goes without saying that the illustrated pattern may be reversed vertically or horizontally symmetrically with respect to the horizontal or vertical center line of the window glass.

As described above, the present invention provides the first and second antennas on the windshield of the automobile, and detects the reception status of these radio waves and switches to receive the radio waves. Therefore, it is possible to perform so-called space diversity reception. In particular, it is possible to obtain a high-quality received signal in which the influence of fluctuations in reception level (7 aging) caused by movement of the reception point is reduced. Also, since the first antenna has at least a horizontal (horizontal) element and the second antenna has at least a vertical (vertical) element, the polarization plane of the received wave (
It is possible to perform polarization fidelity reception by taking advantage of the fact that fading conditions differ for each antenna depending on whether the antenna is vertically polarized or horizontally polarized, so that reception characteristics do not change significantly between vertically polarized and horizontally polarized regions It is possible to do so.

[Brief explanation of the drawing]

Fig. 1 is a front view and electric circuit diagram of an automobile windshield showing one embodiment of the present invention, Fig. 2 is a front view showing a restricted area of the antenna wiring position on the windshield, and Fig. 6 is a front view of an automobile windshield showing one embodiment of the present invention. A block circuit diagram of the FM receiver used, FIGS. 4 to 16 are front views of a windshield showing various modifications of the antenna turn, and FIG. 17 is a directional characteristic diagram of the antenna. In addition, in the symbols used in the drawings (1)...
・・・・・・・・・・・・Windshield (2)・・・・
・・・・・・・・・・・・First antenna (3)・・・・
......Second antenna (b)...
・・・・・・・・・・・・Choice switch circuit－・・・・・・
・・・・・・・・・Automatic level setting circuit■・・・・・・
......This is an antenna switching control circuit. Agent Masaru Ueya Figure 6, Figure 8, Figure 10, Figure 7, Figure 9, Figure 11

Claims (1)

[Claims] A first antenna line having at least a horizontal element and a second antenna line having at least a vertical element, each provided on a windshield of an automobile, and the radio wave reception state of the first and second antenna lines. A receiver for an automobile, comprising a detecting means and a changeover switch means for selecting and receiving the first or second antenna line according to the output of the detecting means.