JPS5870641A - Receiver for car - Google Patents

Abstract

PURPOSE:To perform diveristy reception by using a heating conductor wire groups of a window glass of a car as one of antennas. CONSTITUTION:A window glass of a car is provided with an antenna conductor wire group 10, and this group 10 and a heating conductor wire group 2 (for defrosting) are connected to a changeover switch 17. The switch 17 is automatically switched with a reception level detection signal or an FM multi-path distortion detecting signal (to detect distortion of a stereo pilot signal of 19kHz) to select either the group 2 or the group 10. In Figure, 3 is a power supply for heating, 8 is a high frequency choke coil and 9 is a decoupling capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radio reception device using a glass antenna for radio reception provided on a window glass of an automobile, and is particularly suitable for use in a reception system of the map city reception method.

When a moving car receives radio waves such as FM broadcasts, periodic fading occurs due to fluctuations in the field strength of the received radio waves in the direction of travel, and multi-noise distortion occurs due to movement of the receiving point. The received sound quality is likely to deteriorate due to fluctuations, etc. In particular, the received sound may be interrupted in short intervals, making it difficult to recognize the received content.

The present invention provides a receiving system that can solve this problem.

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

FIG. 1 is a front view of a rear window of an automobile and an electric circuit diagram showing a first embodiment of the present invention. In Figure 1, a group of conductive wires (2) for heating to prevent fogging is provided on the rear window glass (1) of an automobile, and these conductive wires are connected to a switch (4) from a battery (3). ) through busbar (5)
(6) A heating current is passed through (7). In order to keep the heating conductive wire group (2) above the ground point in the high frequency band, a high frequency choke coil (8) exhibiting an extremely high impedance in the radio frequency band is attached to the pair of feed lines.
is inserted. Also, patch to prevent noise from the power supply line from entering the received signal! , 1-(3) and a grounding point, a decoupling capacitor (9) is inserted.

An antenna wire group αQ for FM reception is provided above the heating conductive wire group (2). This antenna line group (g) consists of six upper and lower parallel lines (12a) (12b) (12
c) and one line (13a) (13a) arranged above and below this main antenna.
16b), respectively.

The lower auxiliary antenna output (13b) converts the received waves induced from the heating conductive wire group (2) into the main antenna wire (12).
The main antenna wire (12(!)) is attached to the main antenna wire (12(!
) is combined with

The upper auxiliary antenna wire (13a) is also attached for the purpose of obtaining omnidirectional characteristics, and is connected to the main antenna wire (12b) at a tuning point located off the center line via a connecting wire Q4. Auxiliary antenna (13a)
and the uppermost main antenna wire (12a) are closely opposed to each other over a predetermined length, and directivity is also improved by guidance between the two.

In one preferred embodiment, the auxiliary antenna wire (13
m), the horizontal lengths of the connecting wire (b) and the auxiliary antenna (ISb) are 600 cm, 350 cm, and 700 cm, respectively, and the window frame of the joint between the main antenna wire (12b) and (120) The distance from
The opposing length of the main antenna line (12 m) is 100 tones.

The output of the main antenna (2) is led out from the feed point (to) to the switch circuit aη via the preamplifier (2).

On the other hand, in this embodiment, the heating conductive wire group (2) is also used as an antenna, and its output is output from the middle point of the heating conductive wire group (2) at the lowest stage, performing phase matching and functioning as an auxiliary antenna. The signal is led out to the feed point (6) through the nine turns Qll of the conductive wire, and from there is supplied to the AM receiver via the Noriamp... The received signal obtained from the feed point a1 is also branched to a Noriamp (c) for FM reception, and is also led out to the switch circuit σ. This switch circuit αη is designed to minimize the influence of periodic fluctuations in fading or multipath distortion, which occur as the receiving point moves when the car is moving, on the received sound quality. The better antenna output (f
The output can be switched to the (output) or (output) side.

The antenna output selected in the switch circuit αη is F
M receiver.

FIG. 2 is a block circuit diagram of the FM receiver used in this embodiment. In FIG. 2, the received signal received by the antenna (2) or heating conductive wire group (2) is selected by the switch circuit 0 also shown in FIG. ). In this front end and IF circuit (foundation), tuning amplification width,
The received signal that has undergone intermediate frequency conversion and FM detection is supplied to the multiplexer (2) via a high-frequency cut control filter (2) and a noise planker, where it is stereo demodulated and output as R channel and L channel. The signal is led out from the terminal to the audio power amplifier. Note that the multiplexer (B) is supplied with a control signal C such as a stereo/monaural automatic switching signal from the IF circuit (2).

In the front end and IF circuit (c), the reception signal level is detected (level detection of IF output or detection output) in order to mute detuning noise between stations, and the reception level drops to a certain level. The detection output is muted when This reception signal level detection signal a is muted in the IF circuit (c)! circuit and is sent to the automatic level setting circuit (sub). This automatic level setting circuit (2) switches according to the switching frequency.When the threshold of the input level for the analysis changes is below the threshold of ib, the detection signal b is detected.
occurs. This detection signal is sent to the antenna switching control circuit, which in turn sends approximately 100% of the output of the clock generator).
A switching pulse d is formed in synchronization with the clock of Kt (z). This switching pulse d is applied to the trigger input of a T-type flip
The fourth output (Q, Q) is inverted.

The ζ output and the 4 output of the 7 rig 70 tsugu (2) are used as switching control signals for the switch circuit η. For example, when the received signal level of the antenna wire group αQ falls below the set reference value, the flip-flop f4 is Inversely, the ζ output becomes a low level, and the other ζ output becomes a high level and is switched to the antenna output of the group of heating conductive wires (2). The four outputs of the F70 wire are also applied to an automatic level setting circuit, and its operating mode is switched so that this circuit detects a drop in the reception level of the heating conductive wire group (2). Therefore, the next time the reception level of the group of heating conductive wires (2) falls below the set reference level, the automatic level setting circuit) detects this, and based on the detected output, the antenna switching control circuit (the automatic level setting circuit) detects this. ), the switching signal d is generated again, and this switching signal d inverts the switching signal d to 7 rigs. Therefore, the switch circuit α power is switched to the even antenna wire group α0.

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. 2, variations in multipath distortion are detected and reception can be performed by switching to the antenna output direction with less distortion. In other words, the output of the front end and IF circuit is also fed to the 19 KHz pantonose filter, and you can hear the stereo sound here! ?
The pilot signal is extracted. This pilot signal is given to a level fluctuation detection circuit (b). If Martino 4'
If the received signal is distorted by the pilot signal, the pilot signal will also be distorted, so by detecting the level fluctuation (variation in the distortion component), it is possible to detect an increase or decrease in multipath distortion due to movement of the receiving point. .

When the multipath distortion increases by more than a certain amount, the output e of the level fluctuation detection circuit 6 is used to control the high frequency cut control filter (
c) is operated, and the high-frequency distortion component of the detection output is cut and given to the multiplexer.

At the same time, the output e of the level fluctuation detection circuit 6]) is also sent to the antenna switching control circuit (2), and the switching pulse d is formed as described above, and the output e of the level fluctuation detection circuit 6]) is sent to the antenna switching control circuit (2), and as described above, the switching pulse d is formed and the output e of the level fluctuation detection circuit 6]) is sent to the antenna switching control circuit (2). Switched to output.

As a result, a received signal with less multipath distortion can be obtained. In the antenna switching control circuit, a switching signal d is formed when either one of the outputs (i) and (e) of the automatic level setting circuit and the level fluctuation detection circuit (Cl1) is input. In other words, pJ is switched by OR logic with signal S and e.
? A rule d is created. In addition, to prevent antenna switching due to reception level fluctuations during tuning, the reception level detection signal a obtained from the front end and IF circuit (c) is used as an operation prohibition signal to the antenna switching control circuit (c).
This prohibits the formation of a switching signal 9 in the weak electric field between stations during channel selection.

FIG. 6 is a graph showing the fluctuation of the reception level due to the movement of the reception point when using the antenna/arm turn shown in FIG. is FM
It shows the received signal level (dB) to the radio receiver. Further, a dashed-dotted line j indicates the reception level of the antenna wire group αQ in FIG. 1, and a dotted line indicates the reception level of the heating conductive wire group (2). According to the receiving circuit shown in FIG.
When the reception level is constant and falls below the height L while receiving with the antenna wire group αQ shown in the figure, the reception output is switched to the heating conductive wire group (2), and the heating conductive wire group When the reception level drops below a certain level while receiving by the antenna wire group (2), the antenna wire group α
It is switched to the Q output. As a result, reception can always be made at a good level, and there is no periodic loss of received sound as the vehicle travels.

Fig. 4 is a graph showing the directivity of the antenna pattern in Fig. 1, where the solid line shows the reception level of the antenna wire group α1, and the dotted line shows the reception level by the heating conductive wire group (2). ing. As shown in FIG. 4, since the directivity characteristics of both are substantially uniform, it is possible to obtain received signals that can complement each other by switching as shown in FIG. 6. Depending on the azimuth, there may be cases where the average values of the received levels of the outputs of the two antennas are different, but even in this case, the receiving signal with the higher level is selected in the receiving circuit of FIG. 2.

Next, FIG. 5 shows a second embodiment of the glass antenna according to the present invention. In Fig. 5, the antenna wire group (
The same 74 turns as in FIG. 1 are used as the heating conductive wire group (2), and the receiving output is obtained directly from the bus bar (5) of the heating conductive wire group (2). The output of the main antenna (2) and the reception output of the group of heating conductive wires (2) pass through preamplifiers (to) (c), are switched by a switch circuit (b), and are fed to the FM7M end of the radio receiver. It will be done. In addition, the respective outputs of the main antenna (2) and heating conductive wire group (2) are mixed in an impedance matching coil (E), and from the midpoint tag of this coil, an AM reception/reception signal is sent to the preamplifier wire. The signal is supplied to the AM section of the radio receiver (2) via the radio receiver (2).

Switching of the switch circuit (b) is performed in the same manner as shown in FIG.

As described above, according to the present invention, the reception signal from the heating conductive wire group and the reception signal from the antenna wire group are switched and received, so that diversity reception can be performed without attaching a special antenna. In particular, it is possible to obtain high-quality received sound in which the influence of reception level fluctuations (fading) that occur due to movement of the reception point is reduced. In addition, there is no need to provide a pair of antennas and arm turns for diversity reception, and the group of heating conductive wires is used as one antenna, so it can be used as an antenna with high reception efficiency within the limited space of an automobile window glass. It is possible to add a pattern.

[Brief explanation of the drawing]

FIG. 1 is a front view and electrical circuit diagram of a rear window of a car showing a first embodiment of the present invention, FIG. 2 is a block circuit diagram of an FM receiver used in the embodiment of FIG. 1, and FIG. A graph showing the fluctuation of the reception level due to the movement of the consumption point when using the antenna pattern shown in Figure 1.
FIG. 5 is a front view and electric circuit diagram similar to FIG. 1 showing a second embodiment of the present invention. In addition, in the symbols used in the drawings, (1)...
・・・・・・・・・・・・Window f 9 S(2)...
...... Heating conductive wire group QO...
・・・・・・・・・Antenna wire group (foundation)...
・・・・・・・・・・・・Switch circuit (goods)・・・・
・・・・・・・・・Automatic level setting circuit (foundation)・・
・・・・・・・・・・・・Antenna switching control circuit. Agent Masaru Ueya

Claims (1)

[Scope of Claims] 1. A group of nine heating conductive wires attached to the surface of an automobile window and an f-box, a group of antenna wires attached in parallel to this group of heating conductive wires, and the above-mentioned heating conductive wire group. means for detecting the radio wave reception state of the conductive wire group and the antenna wire group; and a changeover switch means for selecting and receiving the antenna wire group through the heating conductive wire group hole according to the output of the detecting means. An automobile receiving device comprising: 2. The scope of claims, wherein the radio wave reception state detection means includes a portion for detecting FM multipath distortion, and the changeover switch means performs a switching operation in accordance with a reception level detection signal and a multipath distortion detection signal. The automotive receiving device according to item 1. 6. The output of the changeover switch means is given to the receiver as an FM reception signal, and the reception output of the heating conductive wire group is delivered to the receiver as an AM reception signal. Receiving device for automobiles in scope 1.