CA2183385A1

CA2183385A1 - Reversed phase audio frequency dividing circuit

Info

Publication number: CA2183385A1
Application number: CA002183385A
Authority: CA
Inventors: Kuang Chih Hsu
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-08-28
Filing date: 1996-08-15
Publication date: 1997-03-01
Also published as: CN2234165Y; GB2309352B; GB2309352A; GB9601163D0; DK89496A

Abstract

A reversed phase audio frequency dividing circuit including a master circuit connected between the input terminal and sound coil of a speaker, and a sub-circuit connected in parallel to the master circuit, the master circuit having filter capacitor means for removing audio frequency of predetermined range, the sub-circuit having capacitor means for removing audio frequency of predetermined range, and a reversed phase coil connected with the sound coil of the speaker to a grounding terminal.

Description

21 ~3385 TITLE: A REVERSED PHASE AUDI0 rKEQ~J~;NcY DIVIDING CIRCUIT

This invention relates to a reversed phase audio frequency dividing circuit.
The use of a speaker can properly amplify a sound 5 source. A speaker generally has a plurality of resistive-capacitive filters for filtering audio frequency passing through, therefore unpleasant and noisy audio f requency can be removed . In order to improve sound quality, several audio response units are installed for 10 responding different audio frequency. When several audio response units are installed, suitable filter means must be used to remove unqualified audio frequency from passing through the respective audio response units. Figure lA
shows a regular audio filter designed for removing low 15 frequency, in which a plurality of capacitors C1, C2, C3 are respectively connected in series to the audio input terminal IN, and a plurality of resistors R1 are respectively connected in parallel to each capacitor.
Figure 2 shows the response curves of the audio frequency 20 before and after passing through the filters, in which the 21 ~33~5 response curve Aa is the original audio frequency response curve; the response curve Bb is the audio f requency response curve obtained from that filtered through Cl;
the response curve Cc is the audio frequency response S curve obtained f rom that f iltered through Cl and C2; the response curve Dd is that audio frequency response curve obtained f rom that f iltered through Cl, C2, and C3 .
Figure lB shows a regular audio filter designed for removing high frequency, in which a plurality of inductors 10 Ll, L2, L3 are respectively connected in series to the audio input terminal IN, and a plurality of capacitors Cl, C2, C3 are respectively connected in parallel to each inductor. From Figure 2, we can see that the gain of output power is greatly reduced when the sound source is 15 f iltered through several f ilters . Because the gain of output power will be greatly reduced if the sound source is f iltered through several f ilters, the original power of the sound source must be relatively increased so that the output power of the speaker can be increased. However, 20 because there is a limitation on the output power of 21 B33~5 regular audio equipment, it is difficult to compensate the loss of gain due to the operation of f ilters .
This invention is directed to a reversed phase audio frequency dividing circuit.
S According to the present invention, undesired high and low audio frequency is eliminated when positive phase audio freguency offsets negative phase audio frequency, therefore the sound guality of each sound discrimination speaker is improved.
Other objects of the invention will in part be obvious and in part hereinaf ter pointed out .
The invention accordingly consists of features of constructions and method, combination of elements, arrangement of parts and steps of the method which will be exemplified in the constructions and method hereinafter disclosed, the scope of the application of which will be indicated in the claims following.
FIG. lA is a circuit diagram of a low frequency f ilter circuit according to the prior art;
FIG. lB is a circuit diagram of a high frequency 21 ~33~5 filter circuit according to the prior art;
FIG. 2 is the response curves of the audio frequency before and after passing through the filters of the low frequency f ilter circuit of FIG. lA;
FIG. 3A is a circuit diagram of a low-pass f ilter according to the present invention;
FIG. 3B is an alternate form of the low-pass filter of FIG. 3A;
FIG. 4 is an audio frequency response curve obtained from the low-pass filter of FIG. 3i FIG. 5A is a circuit diagram of an intermediate-pass filter according to the present invention;
FIG. 5B shows an alternate form of the intermediate-pass f ilter of FIG. 5A; and FIG. 6 is an audio frequency response curve obtained from the intermediate-pass f ilter of FIG. 5 .
For purpose to promoting an understanding of the principles Qf the invention, reference will now be made to the embodiment illustrated in the drawings. Specific 20 language will be used to describe same. It will, 21 833~5 s nevertheless, be understood that no limitation of the scope of the invention is thereby intended, such alternations and further modif ications in the illustrated device, and such further applications of the principles of 5 the invention as illustrated herein being contemplated as would normally occur to one skilled in the art to which the invention relates.
Ref erring to FIG . 3A and 4, sound source input terminal is connected to the master sound coil Lm of the 10 speaker by a main circuit. A sub-circuit is connected in parallel to the main circuit. The sub-circuit comprises a high-pass capacitor Cx at the front end, which permits limited intermediate and high frequency to pass, and an auxiliary sound coil Lx of reversed phase relative to the 15 master sound coil Lm at the rear end. The output terminal of the auxiliary sound coil Lx and the output terminal of the master sound coil Lm are connected in series to grounding terminal. Because the auxiliary sound coil Lx provides an intermediate/high frequency sound signal of ZO reversed phase, it offsets int~ te/high frequency sound waves fro~ the main circuit. Therefore, the area defined by B, C, and D in FIG. 4 offsets the relative upper triangular area above A and C, and the audio frequency wavelength curve can extend to D. This S arrangement completely eliminates high frequency sound effect. This low-pass filter further comprises a variable resistor Rl for regulating the volume of the output signal of the sub-circuit . The low-pass f ilter can be arranged in another form as shown in FIG. 3B.
Referring to FIG. 5A and 6, the design of the intermediate-pass filter is similar to that of the aforesaid low-pass filter. The main circuit is connected between the sound source input terminal IN and the master sound coil LM. A capacitor Cl is installed in the main 15 circuit of the intermediate-pass f ilter to remove low frequency from inputted sound source. A high-pass capacitor Cx is connected in parallel to the input end of the main circuit for letting high frequency pass. An auxiliary sound coil Lx of reversed phase and a variable 20 resistor Rl are connected in series to the master sound coil LM. Therefore, high frequency and low sound frequency are removed from the sound source when the sound source passes through the intermediate pass f ilter, and only the intermediate frequency sound are is left (see 5 Figure 6 ) . Furthermore, the intermediate-pass f ilter can be arranged in another form as shown in Figure 5B.
Referring to FIGS. 4 and 6 again, the design of the reversed phase audio frequency dividing circuit causes little loss of the gain. Therefore, sound effect output 10 can be greatly increased, and sound quality can be greatly improved. Because the f ilter uses only an auxiliary sound coil of reversed phase to match with different capacitors C1, Cx, the structure is simple, and the installation is easy .
The invention is naturally not limited in any sense to the particular features specified in the forgoing or to the details of the particular embodiment which has been chosen in order to illustrate the invention.
Consideration can be given to all kinds of variants of the 20 particular embodiment which has been described by way of 21 833~5 example and of its constituent elements without thereby departing from the scope of the invention. This invention accordingly includes all the means constituting technical equivalents of the means described as well as their S combinations.

Claims

1. A reversed phase audio frequency dividing circuit comprising a master circuit connected between the input terminal and sound coil of a speaker, and a sub-circuit connected in parallel to said master circuit, said master circuit comprising filter capacitor means for removing audio frequency of predetermined range, said sub-circuit comprising capacitor means for removing audio frequency of predetermined range, and a reversed phase coil connected with the sound coil of said speaker to a grounding terminal.

2. The reversed phase audio frequency dividing circuit as claimed in Claim 1 wherein the sound coil of said speaker has an intermediate section connected to a grounding terminal.

3. The reversed phase audio frequency dividing circuit as claimed in Claim 1 wherein said sub-circuit further comprises a variable resistor for regulating the volume of the audio frequency passing through.