JPS5816277Y2 - Receiver with antenna with variable capacitance diode - Google Patents

Description

[Detailed description of the invention] The present invention relates to a receiver equipped with an antenna equipped with a variable capacitance diode.The bar antenna body has a variable capacitance diode connected to the bar antenna coil, and the variable capacitance diode is connected to the local generator coil. The bar antenna can be detachably attached to the receiver body, and tuned by applying a control voltage to these variable capacitance diodes. To provide a receiver which can be used separately from the main body of the bar antenna and which can receive signals with high sensitivity without causing a drop in Q even if the main body of the bar antenna and the main body of the receiver are installed separated from each other.

In a general superheterodyne AM receiver,
As shown in Figure 1, a variable capacitor (hereinafter referred to as variable capacitor 5) CVl for channel selection is connected to the bar antenna coil (lenoid antenna coil) 1 of the high frequency amplification stage and is connected to the local oscillation coil 2 of the local oscillation stage. The variable capacitor Cv2 for local oscillation same wave number tuning is mechanically interlocked by gears, strings, etc. Therefore, the bar antenna coil 1 of the high frequency amplification stage and the local oscillation stage are necessarily installed separately. It is said to have an unbelievable composition.

On the other hand, in a stationary receiver, a bar antenna coil is mounted on the back side of the receiver body so as to face in the direction that provides the best reception sensitivity.

However, receivers are generally installed indoors with low electric field strength, such as reinforced concrete or mortar, and in order to obtain sufficient reception sensitivity, the bar antenna coil 1 must be placed at an appropriate position in the conventional receiver described above. However, since the receiver cannot be installed anywhere in the area, the entire receiver must be installed near a window, or an outdoor antenna must be connected.

In this case, it is possible to install the variable capacitors Cv1 and CV2 in the receiver body and install the bar antenna coil 1 away from the receiver body, but if you do this, the terminal ■ of the bar antenna coil 1 and the ground During this period, stray capacitance increases, Q decreases, and reception sensitivity decreases, making it impractical.

The present invention eliminates the above-mentioned drawbacks, and one embodiment thereof will be described with reference to FIGS.

FIG. 2 shows a circuit diagram of a main part of an embodiment of a receiver incorporating a variable capacitance diode-equipped antenna according to the present invention.

In the figure, reference numeral 3 denotes a bar antenna body, which is composed of a bar antenna coil 4, a variable capacitance diode (hereinafter referred to as a varactor diode) Dl connected in parallel with the bar antenna coil 4, a resistor R1, and a capacitor C1.

Reference numeral 5 designates the receiver main body, which includes a local oscillation stage consisting of a local oscillation coil 6 and a varactor diode D2, a resistor R2, a capacitor C2, etc. connected in parallel with the local oscillation coil 6, and a bar antenna main body 3 and lead wires t1 to t1. Connected at t3.

Reference numeral 1 denotes a varactor diode control voltage application terminal, which is provided in the receiver body 5 and is connected to the varactor diode D2 via a resistor R2, as well as to the varactor diode D1 via a lead wire t2 and a resistor R1. has been done.

In addition to the circuit shown in FIG. 1, the receiver main body 5 is provided with various circuit elements such as a transistor in the high frequency amplification stage, each element in the mixing stage, and a transistor in the local oscillation stage. Since it is not directly related to the gist and the operation is well known,
The circuit diagram is omitted.

The bar anchor main body 3 is, for example, as shown in FIG.
A resin case 3a containing a bar antenna coil, a varactor diode, a resistor, and a capacitor (not shown) may be supported by a support portion 3b to which a suction cup 3b' is attached, or as shown in FIG. As shown, a case 3a containing a bar antenna coil, a varactor diode, etc. is supported by a support portion 3c to which a stand 3c' is attached.

The bar antenna main body 3 and the lead wires t1 to t3 are normally fixed to the back side of the receiver main body 5 with appropriate members in a removable manner, as shown in FIGS. 5A and 5B, depending on the place of use. By appropriately stretching the lead wires t1 to t3, the bar antenna main body 3 can be installed at an appropriate location away from the receiver main body by means of a suction cup, a stand, or the like.

Next, the operation of the receiver configured above will be explained.

In FIG. 2, when the voltage applied to the varactor diode control voltage application terminal 7 is adjusted appropriately when selecting a channel, the varactor diode D1. Both D2 have their capacitances changed by changing the bias voltage in the reverse direction.

As a result, the resonant frequencies of the resonant circuit including the bar antenna coil 4 and the resonant circuit including the local oscillation coil 6 change simultaneously, and the capacitances of the variable capacitors CV and Cv2 shown in FIG. At the same time, the frequency of the resonant circuit including the bar antenna coil 4 is changed to perform tuning, and at the same time, the same wave number of the resonant circuit including the local oscillation coil 6 is changed. It is varied and local tuning is performed.

At this time, since the bar antenna coil 4 and the varactor diode D1 are integrally configured as a resonant circuit, in the conventional example shown in FIG. The impedance is lower than that connected by wire.

Thereby, the existence of stray capacitance between the bar antenna main body 3 and the ground can be substantially ignored, and therefore the stray capacitance caused by the connection of the one-node lines t1 to t3 can be ignored.

Therefore, even if the bar antenna main body 3 and the receiver main body 5 are installed separately, the Q will not decrease.For this reason, when the receiver main body 5 is installed indoors with low electric field strength,
In order to obtain the best reception sensitivity, it is sufficient to stretch the lead wires t1 to t3 and install the bar antenna main body 3 in an appropriate place such as near a window, away from the receiver main body 5. There is no need to install the entire receiver near a window or to install a special outdoor antenna.

Note that the resistors R1, R2 and capacitors C1, C2 provided in the bar antenna main body 3 and the receiver main body 5 are designed to prevent the RF acid component from being supplied to the varactor diode control voltage application terminal T side. , but not necessarily.

Further, for example, a potentiometer or the like may be connected to the varactor diode control voltage application terminal 7, and the frequency may be displayed using a numerical value corresponding to the magnitude of the control voltage.

As mentioned above, the receiver having the variable capacitance diode antenna according to the present invention includes a receiver main body including a local oscillation coil, a first variable capacitance diode connected to the local oscillation coil and to which a control voltage is applied, and a bar. It has an antenna coil and a second variable capacitance diode connected to the antenna coil, is detachably fixed to the receiver body, and is provided with one unit so that it can be installed at a location away from the receiver body. Connect the bar antenna body, the receiver body, and the bar antenna body.
It consists of a lead wire that supplies the control voltage to the second variable capacitance diode of the bar antenna body and the reception signal of the bar antenna body to the receiver body, so the bar antenna body can be removed from the receiver body as necessary. The bar antenna main body can be installed at a desired location depending on the strength of the electric field, such as by being installed or attached thereto, and the resonance caused by the bar antenna coil and the second variable capacitance diode. Since the circuit is integrally constructed, the impedance of the bar antenna body can be made smaller than that of conventional ones, and as a result, the existence of stray capacitance between the bar antenna body and the ground can be virtually ignored, and the bar When the antenna body and the receiver body are connected by a lead wire, the stray capacitance caused by the lead wire can be ignored, and therefore, even if the bar antenna body and the receiver body are installed separately, the Q will not decrease. For this reason, if the receiver is installed indoors with low electric field strength, in order to obtain the best reception sensitivity, it is necessary to stretch the lead wire and separate the bar antenna from the receiver to a suitable location such as near a window. It has the advantage of not having to install the entire receiver next to a window or installing a special outdoor antenna like conventional receivers.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of the main parts of an example of a conventional receiver, Figure 2 is a circuit diagram of the main parts of an embodiment of the receiver of the present invention, and Figures 3 and 4 are used in the receiver of the present invention. FIG. 5A is a schematic perspective view of each embodiment of the bar antenna main body. B is a schematic perspective view of the receiver of the present invention. 3... Bar antenna body, 3b... Suction cup, 3c'... Placement stand, 4... Bar antenna coil, 5... Receiving Machine body, 6...
...Local oscillation coil, 1...Varactor diode control voltage application terminal, Dl, D2...Varactor diode, t1-t3...Lead wire.

Claims (1)

[Scope of utility model registration request] A bar receiver body having a curved section oscillation coil and a first variable capacitance diode connected to the coil and to which a control voltage is applied; and a bar antenna coil and a second variable capacitance diode connected to the coil. a bar antenna body which is removably fixed to the receiver body and is provided with a base so that it can be installed at a location apart from the receiver body; the receiver body and the burner antenna body; an antenna with a variable capacitance diode, which is connected to a lead wire to supply the control voltage to the second variable capacitance diode of the burner antenna main body, and to supply a received signal of the burner antenna main body to the receiver main body. Receiving machine.