JPS59204307A - Eliminating device of disturbing signal - Google Patents

Abstract

PURPOSE:To secure the ability to exclude an external disturbing signal without exerting any evil influence upon the original performance of an acoustic equipment, by forming part of a signal transmission line of a magnetic body. CONSTITUTION:The 1st and the 2nd conductive patterns 11 and 12 which transmit sound signals are fixed to an insulating substrate 10. Those 1st and the 2nd conductive patterns 11 and 12 are cut partially and their cut parts are connected electrically to a speaker terminal 15 directly or through lead wires 13 and 14. This terminal 15 is connected to a speaker or another acoustic equipment through a connection cord. Further, the lead wires 13 and 14 are inserted by a cylindrical magnetic body 16. Thus, the ability to exclude external disturbing signals is secured without exerting any evil influence upon the original performance of the acoustic equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an interference signal eliminating device for eliminating external interference signals flowing into input and output terminals of audio equipment, etc.

[Technical background of the invention, etc. Problem 1] External interference signals that flow into audio equipment include television signals, amateur radio, pagers, etc. that jump into radio receivers, and connection cords that connect each audio equipment. Various noise signals jump in, and these external interference signals flow into the power supply line, which has an adverse effect on other television receivers and the like by becoming interference signals. In order to eliminate this effect, it is said that it is better to attenuate the frequencies of 'I 50 kllz and -F for external interference signals flowing into the external connection terminal.

Specifically, in order to eliminate and cover up external interference signals, conventional methods have been used as shown in FIG. FIG. 1 shows an example of use in an amplifier.

In Figure 1, U, 1 is an input terminal, and this input terminal 1
After the audio signal applied to the amplifier 2'c is amplified,
It is led out to a speaker terminal 4 via a coil (Ll) and a resistor (R+) in parallel, and drives a speaker connected from this speaker terminal 4 to a speaker cord (not shown).

Note that one of the capacitors (C1) and (C2) is connected to both ends of the parallel-connected coil (Ll) and resistor (R1), respectively, and the other is grounded. This capacitor (C1) and (
C2) constitutes a low-pass circuit.

In the interference signal eliminating device configured as shown in FIG. 1, external interference signals with a frequency of 150 kHz or more flowing in from the speaker terminal 4 are eliminated by the low-pass circuit of capacitors (C1) and (C2). However, , when the load impedance of amplifier 2 is R, the external 150 kHz
7. In order to eliminate the interference above, the resonant frequency f becomes f=1-m-2π(CI+02)R.

Generally, the load impedance of amplifier 2 is small, and in order to find the resonant frequency f, capacitors (C1) and (C2) are used.
The value of is too small. For this reason, a large capacity capacitor ((CI), ((
This has the drawback that the frequency characteristics and distortion factor of the amplifier are degraded due to 2).

[Object of the Invention] The present invention eliminates the above-mentioned problems, and has a simple configuration that can ensure the ability to eliminate external interference signals without affecting the performance of the original audio equipment. The present invention provides an interference signal eliminating device that has the following features.

[Summary of the Invention] To achieve the above object, an insulating substrate, first and second conductive patterns for transmitting signals fixed to the insulating substrate, and one of the first and second conductive patterns are provided. It consists of lead wires inserted into the respective parts, and external connection terminals connected to the first and second conductive patterns, and each of the lead wires is inserted into a cylindrical magnetic body to eliminate external interference signals. J: Sea urchin.

[Embodiment 1 of the Invention] An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 2, reference numeral 10 denotes an insulating substrate, and 11.12 denotes first and second conductive patterns fixed to the insulating substrate 10 and transmitting audio signals. A portion of the conductive patterns 11.12 is divided, and the divided first and second conductive patterns 11.12 are separated.
The 12 parts are connected by soldering with lead wires 13 and 14, respectively. Then, it is electrically connected to the speaker terminal 15 directly or via the lead wire to the first and second conductive patterns 11.12 in the vicinity connected by the C lead wire 13.14. For connection from 15: Connect to a speaker or Haku's acoustic I prototype via J-C.

16 is a cylindrical magnetic body, and the lead wires 13 and 14 are inserted into this magnetic body 16.

Further, the material forming the magnetic body 16 is specifically, for example, ferrite.

In Fig. 3, a3 is shown (numeral 17 is an input terminal, the audio signal applied to this input terminal 17 is amplified by an amplifier 18, and is passed through a parallel circuit 19 of a coil (Ll) and a resistor (R+) to -C Connected to the first conductive pattern 11 shown in FIG. It is connected to the conductive pattern 12.

FIG. 4 is an equivalent circuit of the circuits shown in FIGS. 2 and 3, ignoring the characteristic impedance and mutual inductance of the signal transmission line, that is, the first and second conductive patterns 11 and 12, and excluding external interference. We are thinking in a state where no signal voltage is received, a so-called balanced mode. In the figure, VS is the balanced mode power supply voltage, and (RL) is the load.

Assuming that an unbalanced shade disturbance signal voltage is applied from an external source in the state shown in the equivalent circuit of FIG. 4 above,
As shown in FIG. 5, it becomes a network consisting of a balanced mode power supply voltage Vs and an unbalanced mode power supply voltage Vc. Note that (Rc+) and (RC2) are the impedances of the signal transmission line in the balanced mode direction, and (RL) is the load.

By the way, the equivalent circuit when the balanced mode power supply voltage VS in FIG. 5 is lowered is shown in FIG.
Find the voltage VN induced in , and assuming that an inductor' (magnetic material 16) with self inductance [l and [2] mutual inductance M is inserted in the A transmission line, the following equation holds true.

Rinawara, Vc =j ωL, +-1+ +j ω'M-I 2
+I I RL... (1) Vc = jωL 2#T 2 +j ωM-I 1 +
RC212・・・・・・(2) From formulas (1) and (2), [,=Vc nikomijunyuu top ・・・(3), j
By substituting equation (3) into equation (1) with θn 1- 2 + Rcz Lr=12=M=1, j ωl-・(Rc 2 +RL )t Rc 2 ・
RL (4) Since VN=II・RL, (jω+RC2,/L). However, 11 and I2 are the first and second n
This is the current flowing through the signal transmission line of rfH pattern 11.12.

This result is shown in FIG. 7. In other words, the inductor inserted in the signal transmission line is L>R
If the value has a relationship of C2/ω, then V N /
It can be seen that V c becomes 0, and the disturbance signal voltage induced in the unbalanced mode is no longer induced in the load.

Therefore, even if there is an external interference signal, by inserting an inductor into the signal transmission line, the interference signal to other electronic devices can be eliminated without flowing into the power supply line.

By the way, as a result of experiments, it is effective to attach the magnetic body 16 as close to the external connection terminal as possible. In addition, in the embodiment, consideration was given to eliminating external interference signals to the speaker terminal of the amplifier.
The present invention is not limited to this, and a similar configuration 4 can be applied to a player 17 connected to an amplifier, a tuner, and even an external input terminal for a tape deck, thereby making it possible to eliminate external interference signals.

It can also be applied to various outlet terminals of players, tuners, tape decks, etc.

[Effects of the Invention] As described above, according to the interference signal eliminating device of the present invention, by inserting a part of the signal transmission line into something made of a magnetic material, the voltage generated by J is reduced in the interference signal. Since this cancels out the interference, it is possible to eliminate the inflow of external interference signals into the power supply line, thereby eliminating interference with other electronic stimulators.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a conventional amplifier, Fig. 2 is a partially cutaway diagram showing an embodiment of the present invention, Fig. 3 is a circuit diagram of an amplifier connected to Fig. 2, and Fig. 4. is C in the equilibrium mode of Figure 3.
-J equivalent circuit diagram, Figure 5 is an equivalent circuit diagram with unbalanced mode added to Figure 3, Figure 6 is an equivalent circuit diagram with only unbalanced mode, Figure 7 is unbalanced mode voltage. FIG. 2 is a characteristic diagram showing the relationship between J and the voltage induced in the load. 10・・・・・・・・・Insulating substrate 1'1.12・
...First and second conductive patterns 13.14...Lead wires 15...Speaker terminals 16...
・・・・・・・・・Patent attorney for magnetic materials Sasa Suyama −

Claims (1)

[Claims] An insulating substrate, first and second conductive patterns for transmitting signals attached to the insulating substrate, and leads inserted into parts of the first and second conductive patterns, respectively. and an external connection terminal connected to the first and second conductive patterns, and each lead wire is inserted into a cylindrical magnetic body to eliminate external interference signals. Interfering signal elimination device.