TW474085B - Impedance blocking filter circuit - Google Patents

Description

A7

474085 V. Description of the invention (1) The present invention is based on the application filed on η B, 1998 on January 19, 1998, and the title of the first arrow of the "impedance blocking filter circuit" is extended to a part of the serial number 09/195522. Application (CIP). [Background of the Invention] [Field of the Invention] The present invention is generally related to long-distance communication systems, and more particularly, telephone lines of public centers ((: · 0 ·), and telephones, such as telephones, which are located in the homes of users and users. In a long-distance communication system in which a telephone user or a customer's terminal device communicates with each other, 'the impedance blocking waver circuit is used to unrestrictively block telephone impedances higher than 20 kHz. [Explanation of Prior Art] Prior to the following US licensed patents Technology is the best example, and research on these patents is relevant to the subject matter of this application: 4,613,732 4,823,383 4,7 42,541 5,642, 4 16 4,743,999 5,802,170 U.S. Patent No. issued to Cardot et al. On April 18, 1989 No. 4,823,383 discloses a protection device for a terminal device located in a telephone user's house. The protection device includes a voltage surge protection circuit and / or a filter for protecting radio frequency and interference. This filter is interconnected by Series inductors LI, L2, L3, and L5 between terminals EΓ and S1 and series inductors 1, 1, L, 2, l4, and L'5 interconnected between terminals E2 and S2 The capacitor C5 is connected between the inductors L2 and L3 and the inductors Lf2 and L4. The surge protection circuit includes thermal resistance g TH1, -------------- install- ------- Order --------- line (please read the precautions on the back before filling this page) Economy; Ministry of Intellectual Property Bureau Consumption • Printed by Feiheshe This paper is applicable to China Standard (CNS) A4 specification (21 × 297 mm) 1 91620 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economy r 474085 A7 -------- 21_______ V. Description of the invention 6) TH2 and voltage limiter D1 -D3. U.S. Patent No. 5,802,170, issued to Smith et al. On September 1, 1998, discloses a user bridge module for connecting telephone company lines and telephone user lines within a telephone network interface device. In one embodiment, the 'custom bridge' module includes overcurrent protection and an RFI filter. The overcurrent protection is formed by resistors 22, 222 and inductors with a positive temperature coefficient. RFI filters are formed by inductors 224a-224c, 226a-226c and capacitors 23 6a-23 6c. Inductors and capacitors are used to form multi-pole low-pass filters. U.S. Patent No. 5,642,416, issued to Hill et al. On June 24, 1997, discloses an electromagnetic interference bypass filter that suppresses radio frequency noise induced on the end of a telephone line power supply and on a looped wire Current. The filter includes first and second inductors 51, 53 and first and second capacitors 41, 43. It is now known that many telephone users or customers often also have personal computers in their premises. Sometimes a '$ brain user receives an ADSL (Asymmetric Digital Subscriber Line) signal from the Internet via the Internet service provider (ISP) over the same telephone line. To increase the speed of downloading messages from the Internet, an ADSL network interface is usually purchased and installed between the incoming telephone line and the user's computer. However, because terminal devices of one or more telephone users, such as telephones, fax machines, and / or answering machines, are also connected to the same telephone line through indoor wiring, the terminal devices may cause ADSL interface problems, which may Severely limit or reduce data rates. Under certain circumstances, when a telephone device has occurred, -------- ^ --------- (Please read the precautions on the back before filling this page) This paper size applies 47 national standards (CNS) A4 specifications (210 X 297 meals) 2 91620 A7 B7 V. Description of the invention ^) Hang the handset holder, and, take the handset holder ", even if it is, Sometimes the telephone terminal is connected to the same frame, and resonance may occur and the impedance value can be reduced to less than μ ohms at a frequency of 500kHz south. To the guide = Regulation 2 can provide impedance blocking wave circuit, used to connect regular rotation Impedance of the telephone terminal device. The blocking filter circuit is a modular module. The impedance is the name of the maintenance department. ^ It is easily connected in series with the telephone that has 51 problems. The end device is connected in series. The beneficial circuit blocks any telephone impedance (eg, material, short circuit, capacitive inductance, resonance, or any combination of the above) that is not limited to 2_frequency. [Introduction to the Invention] The main purpose of this month is to provide impedance blocking遽 ^ wave circuit, can effectively and quickly eliminate Device-AD, interference. The object of the present invention is to provide an impedance blocking filter circuit for connecting to a telephone terminal device which causes irregular input impedance. Another object of the present invention is to provide an impedance blocking filter circuit, which can Use this impedance blocking filter and waver circuit in the long-distance communication system for communicating between the incoming telephone line and the user's terminal device to block the ADSL network interface unit and / or The impedance of the home network interface unit is higher than 20kHz ^ Another object of the present invention is to provide an impedance blocking filter circuit, which is modular in design so that it can be easily connected to the telephone terminal causing the problem. / The present invention Another object is to provide an impedance blocking filter circuit, which is

The paper size and national standard-specifications mo X 297 male fT

I I I --- (Please read the notes on the back before filling this page) Order · _ -4 ------

I 3 91620 474085 A7 ___B7 5. Description of the invention ‘) Consists of 6 inductors, 2 resistors, and a capacitor. According to a preferred embodiment of the present invention, there is provided an impedance blocking filter circuit, which can be used in a long-distance communication system for communicating between an incoming telephone line and a user's terminal device so that no Limitation of the impedance of the user terminal device from the ADSL network interface unit and / or the home network interface unit above 20 kHz. The filter circuit includes first, second and third inductors connected in series between a first input terminal and a first common point. One end of the first inductor is connected to the first input terminal and the other end thereof is connected to one end of the second inductor. The other end of the second inductor is connected to one end of the third inductor. The third sensor connects the other end to the first common point. One end of the first resistor is also connected to the first common point and the other end thereof is connected to the first output terminal. The wavelet circuit also includes fourth, fifth, and sixth inductors connected in series between the second input terminal and the second common point. One end of the fourth inductor is connected to the second input terminal and the other end thereof is connected to one end of the fifth inductor. The fifth inductor connects its other end to one of the sixth inductors. The sixth inductor connects the other end to the second common point. One end of the second resistor is connected to the second common point and the other end thereof is connected to the second output terminal. One end of the capacitor is connected to the first common point and the other end of the capacitor is connected to the second common point. The foregoing is particularly applicable to the disclosure patent application No. 09 / 195,522. The third embodiment of the impedance blocking filter circuit of the present invention, which is added by the application of a series of cases, is quite similar to the schematic diagram of FIG. 3, except that the filter circuit has been modified here. First and second paper sizes of this paper apply Chinese National Standard (CNS) A4 specifications (210 X 297 mm)

-------- Order --------- (Please read the notes on the back before filling this page) Printed by the Ministry of Economic Affairs and Intellectual Property Bureau t Industrial Consumer Corporation 474085

V. Description of the invention (5) Economy • Ministry of Intellectual Property Bureau Employees' Spring Co., Ltd. Printed circuit (tank circuit) replaces the resistor and R2 and connects the reed switch ^ and capacitor ci in series. Therefore, this third embodiment is an improvement of the embodiment of FIG. 3 because it overcomes the problem of the additional shunt capacitance and can eliminate the deterioration of the telephone circuit loss. In addition, the fourth embodiment of the impedance blocking filter circuit of the present invention, which is applied by a partial serial application method, includes all the components of the third embodiment and further includes seventh and eighth inductors connected in series. L7, L8; a second capacitor C2 and a second reed switch K2 connected in series; and a ninth and tenth inductor [9, L10. In the fifth embodiment, the impedance blocking filter circuit provided is quite similar to the schematic diagram of FIG. 3, except that the filter circuit has been modified to remove the resistors R1 and R2 and the spring connected in series with the capacitor ci Switch K1. These four inductors £ 1-1 ^ 4 and reed switch ruler 1 are all placed in a multi-section coil former device so that the internal winding capacitance can be greatly reduced. In the sixth embodiment, the provided impedance blocking filter circuit includes all the components of the fifth embodiment and further includes seventh and eighth inductors L7 and L8 connected in series; a second capacitor C2 and a second capacitor connected in series The second reed switch K2, and the ninth and tenth inductors L9, L10 are also placed in a multi-segment coil bobbin device. [Brief description of the diagram] The above and other objects of the present invention and The advantages will become more apparent by reading the following detailed description and accompanying drawings. The same elements are indicated by the same reference numerals in all drawings, where: Figure 1 shows the central office and the user's telephone Terminal devices communicate with each other ^ -------- ^ --------- ^ (Please read the notes on the back before filling out this page) This paper size is applicable to China National Standard (CNS) A4 specifications ( (210 X 297 mm) 5 91620 474085 A7 printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. The description of the invention (6) of the long-distance communication system as a whole ^ σ million block diagram, this long-distance communication system uses the impedance of the present invention Blocking filter circuit; Figure 2 An exploded perspective view showing one of the modules placed in the impedance blocking filter circuit; FIG. 3 is a schematic circuit diagram showing an impedance blocking circuit, or a w-isolated wave circuit, which is based on the principle of the present invention. Figure 4 shows a schematic circuit diagram of a second embodiment of an impedance blocking filter circuit constructed in accordance with the principles of the present invention; Figure 5 shows the use of the impedance blocking wave filter circuit of Figure 3 for The relationship between the input impedance and frequency as a function of various telephones. Figure 6 is a schematic circuit diagram showing the current-limiting protection circuit that can be used in the wave circuit of Figure 3. Figure 7 is not available for Figure 3. Figure 8 is a schematic circuit diagram of a home network delimiting filter of a filtering circuit; Figure 8 is a schematic circuit diagram showing a third embodiment of an impedance blocking filter circuit according to the present invention; Figure 9 is a diagram showing an impedance blocking according to the present invention A schematic circuit diagram of a fourth embodiment of a filter circuit; FIG. 10 (a) shows a double-wound inductor assembly having one or two reed switches used in the filter circuits of FIGS. 8 and 9 Top plan view; Figure 10 (b) shows a side vertical cross-sectional view of the double-wound inductor device in Figure i0 (a); Figure 11 (a) shows in Figures 8 and 9 Filter circuit for optional use -------- ^ ------- (Please read the note on the back? Matters before filling out this page) This paper size applies to China National Standard (CNS) A4 specifications (21 〇X 297 public love) 6 91620 Printed by the Consumer Property Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 474085 5. Description of the invention (7 A plan view above the current sensing unit for placing an inductor and a reed switch; Section 11 (b) The diagram is a side vertical sectional view of the current sensing unit of FIG. 11 (a); FIG. 12 is a schematic circuit diagram showing the fifth embodiment of the impedance blocking filter circuit using the multi-segment coil bobbin device Figure 13 is a schematic circuit diagram showing a sixth embodiment of an impedance blocking filter circuit using a multi-segment coil bobbin device; Figure 14 (a) is a diagram showing how much is used in the filter circuits of Figures 12 and 13 Side view of section winding device; and 11 --- --------------------------------- order- - ----- Line (Please read the notes on the back before filling in this page). [Explanation of component symbols] 10 Communication system 12 Office center 14 User house 16 Twisted pair (telephone line) 18 Container 20 Telephone exchange center 22 Internet service provider (ISP) 24 Low-pass filter 26 Surge protector 28 , 43 Modem 30 > 41 High-pass filter This paper size applies Chinese National Standard (CNS) A4 (210 X 297 mm) 7 91620 474085 A7 B7 Resistors 224a to 224c, 226a to 226c, 51, 53 Inductors 236a to 236c, 41, 43 Capacitor I * ------------------- Order --------- Line Climbing (Please read the precautions on the back before filling in this Page) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs V. Invention Description (8) 32 34 36 38 40 42 44-46 > 48 > 50 52 54 56 58 59, 59a, 59b, 59c, 59d 60 62 80 66 H 76 '80' 86 '88 70' 72 '78' 90, 92 74 84 110 220-222 Network Interface Device (NID) / Surge Protection Unit Internal (Indoor) Wiring Socket and Plug Unit PC Phone Network Interface unit plug unit base cover circuit board screw wave waver circuit socket cable plug input end output end Protective circuit division filter housing This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 mm) 8 91620 Member of the Ministry of Economics and Intellectual Property Bureau X Printed by Consumer Affairs Agency 9 474085 .A7 ---- B7 ____ V. Description of the invention (9) [Description of the preferred embodiment] Reference is now made to these drawings in detail, wherein the first drawing shows the use of the telephone company's office center (CO) 12 and the user's house 14 via traditional as An overall block diagram of a long-distance communication system 10 interconnected with a transmission medium such as a twisted pair 16. The long-distance communication system 10 uses a plurality of impedance blocking filter circuits constructed in accordance with the principles of the present invention, wherein each impedance blocking chirped wave circuit is housed in a combined container 18. The office center 12 includes a telephone switching center 20 and an Internet service provider (ISP) 22. The telephone switching center 20 transmits a sound signal to the telephone line 16 via the low-pass filter 24 and the surge protector 26. The ISP 22 transmits an AD S L data signal to the modem 28, and this signal is then transmitted to the telephone line i6 through the high-pass filter 30 and the surge protector 26. It can be understood that the voice signal from the telephone switching center 20 and the ADSL data signal from the isp22 may be transmitted to the telephone line 16 at the same time. Furthermore, the audio signal (talk) is located in a bandwidth of 300 to 3400 Hz, and the ADSL data signal is located in a bandwidth of 30 KHz to 2 MHz. The user's house 14 contains a network interface device (NID) / surge protection unit 32. Its input is connected to the incoming telephone line 16 and its output is connected to it via a demarcated RJ-il socket and plug unit 36. User's internal wiring or indoor wiring 34. As shown in the figure, the user's house 14 further includes a plurality of terminal devices, such as a plurality of telephones 40. Occasionally, computer users will borrow * receive data signals transmitted by the ISP 22 from the Internet and download the data to the personal computer 38. In order to effectively download data from the Internet, users can bet to buy this paper in accordance with the Chinese National Standard (CNS) A4 specification (210 X 297 / ^ 7 91620 ---------- 11-¾ ^ -------— Order --------- (Please read the notes on the back before filling this page) 474085 A7 V. Description of the invention (10) (Please read the notes on the back before filling (This page) and install the ADSL network interface unit 42, which is connected between the computer 38 and the RJ-11 socket and plug unit 44. The ADSL network interface unit 42 includes a high-pass filter 41 connected to the RJ-11 unit 44 And the internal modem 43 connected to the computer. The RJ-11 unit 44 is connected to the indoor wiring 34 to receive ADSL signals from the telephone line 16. However, it is worth noting that a plurality of telephones 40 are also passed through the RJ-11 unit 46, 48 and 50 are connected to the same indoor wiring 34. If there is no impedance blocking filter circuit in the present invention, the output impedance from each telephone 40 will be connected in parallel with the input impedance of the ADSL unit 42. The output impedance will be similar to “hanging up the handset from” to, and picking up the handset. Since the birth, there has been a big change, so that when the frequency is at 20JCHZ, it also resonates, or any of the above combinations. This unstable impedance will seriously affect the computer 38 via the ADSL network interface unit. The rate at which ADSL data signals are received at 42. Therefore, the main purpose of the impedance blocking filter circuit of the present invention is to print the impedance from the consumer property cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs from the terminal devices (telephones) of the ADSL unit 42 and the indoor wiring 34. Isolate so that the performance degradation of the ADSL unit 42 can be ruled out. Furthermore, the impedance blocking filter circuit can be used to weaken the ADSL data signal received by the telephone 40 in order to avoid non-linear conversion of the audio band. Furthermore, in order to improve The filter circuit is included in the combined container 18 as required by the user. ^ As best shown in Figure 2, one of the combined containers 18 includes a base 52 and a removable lid connected with a snap button. 54. 52 bases of each paper size are applicable to China National Standard (CNS) A4 specifications (210 X 297 public love) 10 91620 Employees of Intellectual Property Bureau, Ministry of Economic Affairs Printed by the Consumer Cooperative 474085 Five 'invention description (U; brush circuit board 56, which is fixed on the base 52 by screws 58 and electronic circuit components for filter circuits 59 are mounted on the circuit board 56. Combined container One end of 18 has an integrally formed socket 60 for connection to the telephone. This connection can be achieved by inserting an RJ-11 plug (not shown) from the telephone into the socket 60. The other end of the combined container ι8 has a combined type The container 18 extends to a short distance cable 62 of an RJ-11 plug 64, which plug 64 can be connected to indoor wiring. In particular, the plug 64 can be connected to the indoor wiring 34 by inserting the plug 64 into a wall socket (not shown) having an RJ-11 socket. In Fig. 3, a detailed circuit diagram of the impedance blocking filter circuit 59 of the present invention is shown here. This circuit 59 is connected in series between the house wiring 34 and the terminal device (telephone) in Fig. 1. The filter circuit 59 includes two input terminals, tip and ring 66, 68 which can be connected to the indoor wiring 34 via the RJ-11 plug 64, and can be connected to the telephone 40 via the socket 60. Two output terminals (tip and ring) 70, 72. The filter circuit 59 疋 is composed of an inductor L1_L6, a capacitor C1, and resistors R1 and R2. Inductors L5, L3, L1 and resistor R1 are connected in series between the first or pointed input terminal 66 and the first or pointed output terminal 70. Similarly, the inductors L6, L4, L2 and the resistor r2 are connected in series between the second or ring-shaped input terminal 68 and the second or ring-shaped output terminal 72. The inductors L5 and L6 are preferably formed by a ferrite salt toroid. The inductors L3 and L4 have the same inductance value 'and the inductors L1 and L2 also have the same inductance value. The inductor L1 and the first resistor Ri are connected together to the common point a and the capacitor. The paper size is applicable to the Chinese national standard (c ^ f specification (210 X 297 public love) ----- II 91620 ---- II-- ^ -------- (Please read the notes on the back before filling this page) 474085 • A7 B7 V. Description of the invention (12) (Please read the notes on the back before filling this page) One end of C1 The inductor L2 and the second resistor r2 are connected together to the common point B and the other end of the capacitor C1. The resistor sR1 and the resistor ruler 2 have the same value. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs as previously indicated The main purpose of the impedance blocking filter circuit 59 is to prevent the impedance from the telephone with a frequency higher than 30KHz from entering the indoor wiring 34, so that the harmful performance of the ADSL network interface unit 42 can be avoided (Figure 1). Especially 'ADSL data signals in the frequency range of 30KHz and 2MHz are mainly blocked by inductors L1 * L2. However,' Some telephones have encountered input capacitance less than 5nf but can cause resonance impedance in the ADSL band. In order to remove Not subject to For the effect, use capacitor C1 to reduce any resonance to an acceptable deadband, which is about 10KHZ frequency. In addition, capacitor i also provides additional attenuation for the ADSL signal so as to avoid pushing the phone impedance into the non-linear region and avoid The ADSL signal of the south frequency is converted into an audio signal that the user can hear or another adsl frequency ▼ and cause ADSL interference. Although there are other trace resonances in the telephone set within the frequency range of 20kΗζ to 60KHz, but borrow This undesired effect is greatly reduced by the resistors R1 and R2 that produce the de-Q effect. It is important to note that the inductors L1 and L2 are formed by separate inductors, so the problem of vertical impedance and the difference in blocking can be avoided Impedance. Because inductors L1 and L2 have their own frequency limits (eg, self-resonant frequency), inductors L3 and L4 are set so as to block the telephone impedance in the frequency band of i MHz to 20 MHz. When using a home telephone line network at the same time The inductors L3 and L4 are required for the road interface unit (Figure 1) and the ADSL network interface unit 42. They will be described later. Set the inductor ^ 5 China National Standard (CNS) A4 size (210 X 297 Kimiyoshi) 12 91620 L1, L2 L3, L4 L5, L6 Cl R1, R2 474085 A7

5. Description of the invention (13) and L6 in order to block the telephone impedance in the frequency band of 20MHz to 500MHZ, this will prevent any problems caused by TV / FM interference. For the purpose of complete disclosure rather than limitation of the above filter circuit, the following representative values and component labels are proposed. The values and components used in the filter circuit are designed and tested, and therefore provide high quality performance. ____Type or value

10mH 220FH

Ferrous salt toroidal coil, 75FH 20 nf 22 S. By using the above values, you can draw impedance blocking filters for various phone device impedances (eg, open circuit, short circuit, capacitance, inductance, resonance, or any combination of the above) The input impedance of the amplifier circuit 59 as a function of the sum frequency is shown in FIG. From the various curves shown here, it can be seen that for any telephone impedance connected across its output 70 '72, its round impedance across the input 66' 68 of the impedance blocking waver circuit 59 at high frequencies It is equal to or greater than 2K ohms at 40KHz. / The impedance blocking filter circuit 59 in FIG. 3 is basically a second-order pain relief device, and it has been found that when up to 8 or more wave circuits are installed in the long-distance communication system in FIG. 1, the audio band will be appropriately transmitted. Decrease. In order to provide higher attenuation / decrement at frequencies higher than 20 KHz, a schematic circuit diagram of a third-order impedance blocking filter circuit 59a according to the second embodiment of the present invention is shown in FIG. The third-order filter circuit in Figure 4 is essentially the same as in Figure 3-III I ------- I ---- (Please read the precautions on the back before filling this page) Staff of the Intellectual Property Bureau of the Ministry of Economic Affairs Consumption cooperation Du printed This paper applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 13 91620 Α7 V. Description of the invention (w) (Please read the precautions on the back before filling this page) The filter circuit is the same, except that more inductors are added. And inductor L8. The inductor L7 is connected between the common point A and the first resistor 玟 1 ·, and the inductor L8 is connected between the common point B and the second resistor ^ The sensors L7 and L8 have the same value. Based on tests performed on the 4th order third-order waveband circuit, it was found that it provides a higher amount of attenuation at frequencies above 20KHz. However, it was found that the number of third-order wave waver circuits that can be connected to the long-range communication system of FIG. 1 is limited to three or four. This is because the L1, L2, U, and inductor values in Figure 4 (grades of about 5-l0mH) are smaller than those in Figure 3, and the capacitor value of C3 in Figure * (about 33-47nf) (Level) is greater than that in Figure 3, and the additional capacitive load caused by each additional filter circuit will adversely affect the audio band characteristics. Therefore, it was found that the operation between audio performance and ADSL performance is optimal when only three or four filter circuits 59a are installed. Although the filter circuit in Figure 3 can fully perform the function of a wave filter, according to the test conducted by the Intellectual Property Bureau of the Ministry of Economic Affairs and the Employees' Cooperative Cooperative, according to further tests, it is found that when the ringtone signal is at its peak, if the telephone becomes "pick up the handset, A transient problem will occur. Therefore, the transient condition of "picking up the handset holder" will cause it to generate a current spike signal higher than 600 mA. Therefore, this high current will tend to saturate the inductor and thus immediately reduce the input impedance of the filter circuit and therefore adversely affect the data on the ADSL signal transmitted to the interface unit 42. In order to overcome this current transient problem, the present invention develops a fast current limit protection circuit 74, which is used to protect the transient state of the handset when the handset is lifted.丨 I $ 6 _ in the diagram, the current limit protection current shown in this circuit diagram 91620 This paper size is applicable to China National Standard (CNS) A4 specification (21Q x 297 public love 474085

V. Description of the invention (15) Economy. The staff of the Intellectual Property Bureau of the Ministry of Economic Affairs and Consumer Electronics Co., Ltd. printed the road 74. It is composed of modeless N-channel field effect transistors (fet) qi, Q2; resistors Rla, R2a, and variable It is composed of resistors RV1 and RV2. The terminal of the FET qj is connected to the first input terminal 76, the source is connected to one end of the resistor Rla, and the gate is connected to the other end of the resistor Rla. The common point C of the free terminal of the transistor and the resistor Rlai is connected to the first output terminal 78. Similarly, the drain of the FET Q2 is connected to the second input terminal 80, the source is connected to one end of the resistor R2a, and its gate is connected to the other end of the resistor R2a. The common point D of the gate of the transistor Q2 and the resistor R2a is connected to the second output terminal 82. One end of the variable resistor rvI is connected to the drain of the transistor Q1, and the other end is connected to the common point C. One end of the variable resistor RV2 is connected to the drain of the transistor Q2 and the other end is connected to the common point D. In use ', the current limit protection circuit 74 replaces the resistors R1 and R2 in the third figure. The first and second input terminals%, 80 of the protection circuit 74 can be connected to the common points A and bi in FIG. 3 and their first and second input terminals 78, 82 are connected to the pointed shape of FIG. 3 ( tip) and ring outputs 70, 72. Transistors Qi and Q2 are available from Supertex with a similar transistor with part number DN2530N3. The variable resistor is similar to the ZNR type manufactured and sold by Panasonic. The resistors Rla and R2a have the same resistance value, and this resistance value is about 5-20 ohms with the critical values of the transistors Q1 and Q2. It is worth noting that the transistors Q1 and Q2 have a large tolerance on the current limit and the resistors R1a and R2a allow the required current limit value to be adjusted. On the other hand, the values of the resistors R1a and R2a may be 0 ohms or all of them may be removed. / ------------- Installation -------- Order --------- Line (Please read the precautions on the back before filling this page) Applicable to China National Standard (CNS) A4 specification (210 X 297 public love) 15 91620 474085 Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs 91620 A7 B7 V. Description of the invention (16) In the normal operation of hanging the handset, the Crystals Q1 and Q2 are still conductive and have a resistance value of about 10 ohms. When the telephone enters a high ringing voltage because the handset is picked up, the gate-to-source voltage of the forward conducting FET will become a negative voltage due to the resistors Rla and R2a. Therefore, the resistance of the transistors qi and Q2 will become very high, so the current peak value can be limited to about 70-100mA. Transistor qi is used to limit the current flowing in the first direction, and transistor Q2 is used to limit the current flowing in the opposite direction. Furthermore, the variable resistors RV1 and RV2 have a function of a transient current protection device for suppressing transient damage or destruction of the FETs Q1 and Q2 caused by lightning or a short circuit of the power supply. In the past decade, given the increasing use of home computers and the need to access data from the Internet, many users may have multiple PCs at home. As shown in Figure 1, the user's home or small company usually has its second computer 38a connected to the same indoor wiring 34 as well. As shown in the figure, in order to enable high-speed data conversion in a multi-pC environment, it needs a home telephone line network interface unit 42a when the frequency band is higher than 5MHz so as to be able to connect to these multiple computers 38, 38a, or a data rate higher than i〇mb / s other devices. Although the impedance blocking filter circuit of the present invention sufficiently filters and blocks the impedance of the telephone set from the home network signal band in the range of 5-10 MHz, it can be noted that the home network signal from the telephone company still passes the NID / surge protector. The unit 32 is connected to indoor wiring. In order to solve this problem, the present invention develops a home network division filter 84, as shown in the dashed line in FIG. 1, which is connected between the connection 16 from the telephone company and the connection 34 in the customer's house via the division unit "6". Dividing points (NID / surge protector unit 32). The paper size of the home network division filter is applicable to the Chinese National Standard (CNS) A4 specification ⑵G x 297 male J -------- degree 16 (Please read the precautions on the back before filling this page) 1 ______ -—474085 · Α7 ---— B7 Printed by the Economic and Intellectual Property Bureau Staff Consumer Cooperatives V. Description of Invention (17) The schematic circuit diagram is shown in Figure 7. The division filter 84 includes two input terminals (pointer and ring) 86, 88 and two output terminals (pointer and ring) 90, 92 ', wherein the input terminal can pass through the NID / surge protector unit 32 The outlet side of the internal division unit 36 is connected to the telephone line, and the output end is connected to the user's house wiring through the plug side of the division unit 36. The division filter is composed of six inductors L9-L14 and two capacitors C2 and C3. In use, the splitter is permeable to ADSL data signals with a frequency between 30KΗζ and 2 MHz, but it can cause attenuation of ADSL data signals with a frequency greater than 5 MHz by more than 40dB. The division filter will also provide inductive input impedance for the frequency band greater than 5 MIiz, so it can avoid downloading the signal of the home network line on the telephone line and increase the security of the data. From the foregoing detailed description, it can thus be seen that the present invention provides an impedance blocking filter circuit. The impedance blocking filter circuit can be used in a long-distance communication system for connecting a telephone line and a user's terminal device to each other. Limit the impedance above 20kHz from the ADSL network interface unit and / or the home network interface unit on the user terminal device to a limited extent. This impedance blocking filter circuit is composed of six inductors, two resistors, and a capacitor. Although the second-order impedance blocking filter 59 in FIG. 3 and the third-order impedance blocking filter 59a in FIG. 4 can be used to sufficiently block the telephone impedance higher than 20kH2: without limitation, the present invention knows its impedance based on additional tests. Encountered the following shortcomings: (1) the problem of additional capacitors in parallel and (2) the number of such filter circuits connected in parallel to the long-distance communication system in Figure 1 gradually increased the loop attenuation on the telephone. (Please read the precautions on the back before filling in this page) Pack 1 ^ *. -Line. I u _ This paper size is applicable to the national standard (CNS) A4 size ⑵0 x 297 public love) 17 91620 Α7 V. Description of the invention The problem of parallel capacitors is caused by the increased capacitance of all the waver circuits connected to the telephones that are connected to the receivers and receivers. The problem of loop attenuation is actually due to the impedance of the impedance blocking waver circuit connected to the telephone that will pick up the handset, the series inductance will cause resonance in the h KHz frequency range with the total capacitance available, this total capacitance is equal to the line The sum of the capacitance plus the valley of the filter circuit. In addition, as the total capacitance value increases, the frequency will be lower, and the vibration frequency, which will cause phase shifts, will make the telephone's mixing circuit unbalanced. Therefore, it is possible to increase the level of the telephone set when the handset is lifted. In order to overcome this problem, the second embodiment of the present invention is shown in FIG. 8 = the third embodiment of the impedance blocker circuit 59b. The third embodiment includes all circuit elements used in the filter circuit of FIG. 3, except for the resistors R1 and R2, and it also includes a reed switch K1 and is composed of a first and second circuit tci and TC2. Circuit loss protection circuit. In particular, the reed switch K1 connected in series with the capacitor C1 is connected between the common points A and B. Furthermore, the first circuit TC1 is connected in parallel at the common point A and the output. The first winding inductor W1, the capacitor C3, and the resistor R3 between the tip terminals 70. Similarly, the second circuit TC2 is connected in parallel between the common point B and the output ring terminal u The second wire-wound inductor W2, the capacitor C4, and the resistor R4. In addition, a metal-oxygen variable resistor D1 connected in series with the capacitor C1 and connected in parallel with the tile switch K1 may be selected here. Variable resistor D1 is used to protect capacitor C1 as a telephone It can be prevented from being damaged due to transient conditions when the handset is hung. 'Paper size applies to China National Standard (CNS) A4 specification (210 X 297 public) 91620 (Please read the precautions on the back before filling this page) -------- Order --------- line j Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 18 474085 A7 V. Description of the invention (19) In use 'When the telephone becomes, take In the "receiver stand", the flowing sink current will be generated in the first and second winding inductors W1 and W2 (please read the DC 磁场) magnetic field first. This material is only connected to "lifting the handset holder, and the reed switch κι of the telephone circuit 59b can be actuated or turned off by the Dc magnetic field station, gwj field magnetic field. Therefore, it can be removed from" The additional shunt capacitance of all filter circuits connected to the doorphone. Furthermore, the first winding inductor wi and the capacitor C3 of the -th-tunnel circuit TC1 cause resonance to occur at a frequency higher than 2 KHz. First Tun Circuit T. Impedances above the resonance frequency will appear as capacitive reactance, which will obviously offset the inductive reactance of the filter circuit 59b. The resistors decide to set the Q value or slope of the resonance so as to meet the best effect of the impedance of the inductor circuit. In this way, in Lei Yebiao, "If you pick up the handset, you can significantly reduce the return loss," so you can increase the sidephone level of the phone. Similarly, the second circuit of the second circuit TC2 The wound inductor W2, capacitor ^, and resistor are operated in the same manner as the first wound inductors, capacitor C3, and resistor R3 of the -tunnel circuit TC1. Economy, Ministry of Intellectual Property Printed by the employee / facilitator in Figure 9, which shows a fourth embodiment of the impedance blocking waver circuit 59c of the present invention. The fourth embodiment includes all circuit elements of the filter circuit 59b of Figure An inductor is added to the inductor ^ 8. The inductor L7 is connected between the common point A and the first-tunnel circuit τα, and the inductor L8 is connected between the common point B and the second-tunnel circuit tc2. The waver circuit 59c explained so far is obviously a third-order waver = circuit, which provides better termination band performance than the second-order waver circuit 59b in Fig. 8. This paper standard applies to the Chinese National Standard (CNS) A4 specifications (210 X 297 public love —) 19 91620 ^ ί ^ U 0 〇 ^ ί ^ U 0 〇 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 ------ B7 _ (20)-〃 Still refer to Figure 9 and add the second sauce piece switch K2 and Capacitors W and 2 are used to convert the first-order filter circuit into a fourth-order filter circuit. This stem and sigma are used to perform a full-rate better operation on the ADSL modem. In particular, a reed switch connected in series with the capacitor C2 Are connected together between the common points C and D. In addition, a metal-oxygen variable resistor D2 connected in series with the capacitor and connected in parallel with the reed switch K2 is optionally provided. Similarly, the variable resistor D2 It is used to protect the capacitor C2 from being damaged by the transient state when the telephone is in the state of "hanging up the handset holder". Furthermore, an inductor L9 and an inductor L10 are successively added to form a fifth-order filter circuit. In particular, Lei Xian cried + our inductor Is L9 is connected between the inductor L7 at the common point c and the first circuit TC1. The inductor li0 is connected to the inductor L8 at the common point D And the second circuit TC2. In addition to this, the fuse F1 can be selectively The inductors L5, L3, LI, L7, L9 and the first circuit TC1 are connected in series, and are arranged between the input sharp end 66 and the wheel out sharp end 70. For example, the fuse ρ can be electrically connected to Turn in between the pointed end 68 and inductor B. Generally, fuse F1 is actually located adjacent to the inductor or resistor in order to sense the highest temperature in the filter circuit. Fuse F 丨 provides safety measures and should The fuse F1 will open when the temperature sensed in the filter exceeds a certain trip temperature. The fuse is used as a safety protection device to protect the filter circuit from overheating and sparks due to power across the telephone line. In Fig. 10 (a), a top view of a double-wound inductor device T1 used in the filter circuits of Figs. 8 and 9 is shown here. Figure 10 (b) is a side vertical cross-sectional view showing a double-wound inductor device. As shown in the figure, the electric I, ------------------- order --------- line · (Please read the precautions on the back before filling in this (Page) This paper size is in accordance with China National Standard (CNS) A4 (210 X 297 mm) 20 91620 474085 V. Description of the invention (21) (Please read the precautions on the back before filling this page) Sensor device τι includes The cylindrical housing 110 includes a first winding inductor W1 of the first circuit TC1, a second winding inductor W2 of the second circuit TC2, a reed switch K1, and a reed switch K2. . // 一 In Fig. 11 (a), here is a plan view above the current sensing unit CS used in the filter circuits of Figs. 8 and 9. Figure u (b) is a lateral vertical cross-sectional view of the current sensing unit CS. The current sensing unit CS has the shape of a cylindrical case 112 and includes an inductor 1 and a reed switch K. It is obvious to a person skilled in the art that two such electric flu detection units CS can be used instead of the double-wound inductor device τι to perform the same operation. Because the reed switches KI, K2 (K) are used for the windings W1, W2, or inductor L, a reed switch that can be actuated with a loop current threshold of approximately i4-20mA can be selected. If the critical value of the loop current is lower than i4mA, the reed switch may click during the ringing time of 1 REN telephone and the service life of the reed switch may be shortened accordingly. On the other hand, if the critical value of the loop current is higher than 20mA, the loop current may not be sufficient to actuate in the worst case (for example, the longest cable). … Economics • Ministry • Intellectual Property Bureau Employees-Fees • Printed by the agency In Figure 12, the figure shows the fifth embodiment of the impedance blocking waver circuit 59d of the present invention. The fifth embodiment is obviously the same as the first embodiment of the second-order filter circuit in FIG. 3, except that the resistors R1 and R2 are removed and a reed switch connected in series with the capacitor C1 located between the common points A and B is added. Furthermore, the four single inductors LI, L2, L3, and L4 in FIG. 3 are replaced by a multi-segment coil former device T2. It is worth noting that the coil bobbin structure T2 includes a tip winding TW (corresponding to the inductor L1 and L2) connected between the inductor L5 and the common point A, and connected to the inductor L6 and the common. This paper size is applicable to the country of China Standard (CNS) A4 specification (210 X 297 mm) 21 91620 474085 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 V. Description of the invention (22) The loop coil RW between points B (corresponds to the inductor 13, l4). Furthermore, the coil frame structure T2 is provided with reed switches κΐ and K2. The sharp (ring) winding TW (RW) combines the inductor L1 (L2) for the ADSL band (30KHz to 60MHz) and the inductor L3 (L4) for the mid-band (1MHz to 20MHz). Single coil. It has been found that the filter circuit 59d is economical to manufacture and assemble, but the problem of the additional parallel capacitance of the filter circuit of the telephone connected to, hanging on the handset holder, and the like cannot be avoided. Alternatively, a circuit loss protection circuit composed of the first and second circuit TC1 and TC2 may be connected between the common points A and B and the output terminals 70 and 72. In Fig. 13, a sixth embodiment of the impedance blocking filter circuit 59e of the present invention is shown. The sixth embodiment includes all the circuit elements of the filter circuit 59d in FIG. 12 and additionally adds an inductor L7 and an inductor L8. The inductor L7 is connected between the common point eight and the output sharp end, and the inductor L8 is connected between the common point B and the output sharp end 72. The filter circuit described so far is a third-order filter circuit for generating an optimal stop band. ~ Still referring to the 13th, in addition, a second reed switch κ2 and a second capacitor C2 are also added to convert the third-order chirper circuit into a fourth-order chirper circuit. This fourth-order chirper circuit is used in a full-rate ADSL modem. You can get better operation. In particular, the first switch K2 connected in series with the second capacitor 0 is connected between the nodes 0 and D together. Note that the second reed switch K2 is also incorporated in the coil bobbin structure T2.爯 ^ ^ ~ Dan Dan Ran, add inductor L9 to inductor and node E, and add inductor L1 0 to Lei Xian s β 2 ~, iron state L8 and node f, so that The fourth-order filter is crying, and the wire is a ^ L__ The palace / wish / leather circuit is converted into a fifth-order filter. The paper size uses the Chinese National Standard (CNS) A4 specification (210 X 297 male eding 22 91620 (Please read first Note on the back then fill out this page} Order ---------- Line | 474085

5. Description of the Invention (23) Circuit. / 经济 '部 智 • 慧 房产 局 消 # Printed by Cooperative Society 23 In Figure 14 (a), the coil bobbin with multiple sections S1-S4 used in the filter circuit of Figures 12 and 13 is shown here Side view of structure T2. Fig. 14 (b) is a schematic diagram showing the coil bobbin structure T2 of Fig. 14 (a). The coil bobbin structure T2 includes a first narrow section wound with an inductor L3.

Sl 'is wound with the first wide section S2 of the inductor L1, the second narrow section S3 with the inductor L4, and the second wide section S4 with the inductor L2. The sensors L1 and L3 are combined on the same coil and indicated by the pointed winding TW in Fig. 14 (b). Similarly, the inductors L2 and L4 are combined on the same coil and indicated by the pointed winding RW in Fig. 14 (b). In the present invention, the coil bobbin structure T2 is specifically designed to include a narrow section S1 (S3). Because the winding capacitance here is small, a coil with a higher frequency is wound (for example, inductors L3, L4) so that Get the maximum effective frequency range. Furthermore, by dividing the coil bobbin structure T2 into a plurality of sections, the starting point of the pointed (ring) winding TW (RW) at pin 1 (pin 5) can be kept away from pin 4 (pin 8) The end of the sharp (ring) winding. Therefore, the capacitance between windings can be reduced, and the effective frequency range of the coil can be increased. The first reed switch K1 with pins 2 and 7 is placed in the center of the coil bobbin structure T2 so that it can be actuated by the coils TW, RW. Further, a second reed switch K2 having pins 3 and 6 may be formed at the center of the coil bobbin structure T2 so as to be actuated by the same coils TW, RW. / Although the present invention illustrated and described herein has been considered as the best embodiment to the present, those skilled in the art can understand various modifications and amendments, and can Its component replacement is ______70 without deviating from the paper standard. Applicable to China National Standard (CNS) A4 specification (210 X 297 public love) 91620 ^ -------- ^ -------- -Line (Please read the Zhuyin on the back? Matters before filling out this page) 474085 A7

The true scope of the invention. In addition, many modifications can be made to the principle of the invention in order to apply it to special shapes or materials without departing from its central scope. Therefore, 'is not intended to limit the present invention to the specific embodiments disclosed herein as the best mode for carrying out the present invention, but to include the present invention within all the embodiments satisfying the scope of the attached patents. -1 ^ ------------------- Order --------- line (Please read the precautions on the back before filling this page) Intellectual Property of the Ministry of Economic Affairs The paper size printed by the Bureau's Consumer Cooperatives applies the Chinese National Standard (CNS) A4 (210 X 297 mm) 24 91620

Claims (1)

Sixth, the scope of patent application 1 ·-An impedance blocking waver circuit can be used in long-distance communication systems connected to each other between electrical equipment and devices. Symmetric number ^ more stripless (ADSL) network single-discovery / e-e line impedance 7L and / or the impedance of the network interface unit, the aforementioned filter circuit includes: v kIiz a series connection in The first, second and third inductors between the-input terminal and the-common point; the-terminal of the aforementioned-inductor is connected to the aforementioned T-th and: the other terminal thereof is connected to the aforementioned second The “inductor” of the “inductor” = I will be connected to the other end of the inductor to one of the aforementioned inductors 1 ^ ^ μ μ first to the aforementioned first common point; the other end is connected in series The fourth, fifth, and sixth inductors between the second input terminal and the second common point; and a front: a fourth inductor: one terminal is connected to the aforementioned second input_7 terminal to The fifth inductor described in one end of the fifth inductor connects the other end thereof. Connected to one of the aforementioned inductors, the sixth inductor of +, +, and the other inductors are connected to the other-terminal of the second common point described above; one terminal and the second terminal are connected in accordance with direct current (DC) The loop current is equal to the first end of the first switch which is electrically connected to the aforementioned second end. The first terminal is connected to the aforementioned first common point and connected to the front W scale. Applicable to China x 297. Change the capacitor of the first end and the second end of the device. The above switch is "quotation" __έΐ 4740S5 6. Scope of patent application The aforementioned seventh inductor. 5. If the ninth inductor and the tenth wide wave filter circuit of item 4 of the scope of patent application, it further includes a ninth inductor at the aforementioned-node so that its-terminal and the second terminal are connected to the aforementioned / The seventh inductor and its first end are connected at the aforementioned second node: the tenth inductor enables its second end to be connected to the aforementioned eighth inductor 6. If a patent is applied The younger brother of the stalk is a circuit. The 波 -switching device two-wave device circuit described above, in which the front switching device includes the second two: the switch of the Jingjing sheet and the aforementioned second 7 ·, the first vibration circuit described in the patent application for the impedance blocking item 6. The aforementioned & circuit in which the aforementioned first-winding second resonant gate-wire of the second resonant circuit described in the first-winding Eryao line 1 of the other circuit, the other first-type crystal switch, and the aforementioned -κ The chip-open relationship is configured in a double-wound inductor structure. • Impedance blocking wave filter circuit of the 6th item of the scope of interest, the "first-winding and the aforementioned first winding of the first resonant circuit of the" Empirical Resonance Circuit "printed by the Intellectual Property Bureau Staff Consumer Cooperatives II: Configuration There is a current-sensing unit, and the aforementioned second-spectrum vibration current-sensing unit. "The switch is equipped with the 9th, such as the patent application scope of the first impedance blocking waver circuit, and also includes the capacitor Metal-oxygen variable resistors connected in series and connected in parallel with the first switching device. 10.- An impedance blocking filter circuit can be used to enter the long-distance communication system between the telephone line and the user terminal device, so that the paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 27 91620 ^ (ciUQ ^ VI. Patent application scope to block the impedance of the user terminal device called the network unit and / or the home asymmetric digital subscriber line impedance. Above 20kH are connected in series at the first-wheel input end: there are _:-, second and third inductors;-use the -end connection of the first -inductor known between the points and connect the other 1 To the first input end of the aforementioned fan, one of the first step of the first step ... one of the% sensors is connected to the other end of the first step, and the third inductor is connected to the other end. -:! Three to the first common point of the other, the connection is connected in series between the second input terminal and the fourth ..., and the sixth inductor, and the fourth inductor described by the first month j between the points One end is connected to the aforementioned second = and: its other end is connected to the aforementioned fifth inductor. :: The fifth inductor mentioned above is connected to the other end of the front inductor j: Zhongyi Gushanyiyiyi ~, 翊, 翊, the sixth inductor described above is connected to the other end A second common point; a first switching device having a first end and a second end and electrically connecting the first end described above to the aforementioned second end in response to a direct current (DC) loop current; 4. The first end of the first common point and a capacitor connected to the second end of the first end of the switching device, the second end of the switching device is connected to the second common point; and the coil device. 'At least includes windings for reducing the capacitance between windings. Order 91620 6. The scope of the patent application includes a wide section of the aforementioned second electrical appliance, winding, winding of the aforementioned third inductance section, and winding of the aforementioned The useful frequency range of the second narrow region of the sixth inductor is the second wide region of ^ $, so the central area of a switching device can be added. 〇Contains connection at the aforementioned common point; ^ ^ 隔 遽The device circuit also includes a correction circuit device for reducing the apparent return loss caused when the user terminal mutates ^ 4 rounds. Impedance block 12. The impedance block of the correction circuit μΛ as described in the aforementioned patent application range. The waver circuit, which is composed of a route, is connected in parallel between the first common point of the aforementioned first-first oscillator wire and the aforementioned first and second inductors, and the first inductor The first winding is composed of the aforementioned second mis-vibration circuit /: the first-spectrum vibration resistor, and the second mound is connected in parallel with the second and third n / lj, The second winding inductor between the output terminals, Yiyi " Li Zhendian Hong Cry, Yi, and a second resonant resistor. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 13. If the impedance blocking filter circuit of the 12th scope of the patent application is applied, it also includes a seventh inductor and an eighth inductor, of which the first series of the seventh inductor is connected To the first common point of the front ϋ # and the second terminal is connected to the aforementioned first oscillator circuits and the first terminal of the eighth inductor is connected to the aforementioned second common point and the second terminal is connected to the aforementioned The second wrong way. 14 · If you apply for the patent, the impedance blocking filter circuit of item 13 includes 29 Τ620 " 'The patent application scope includes a second switching device and a second suppression device with a first creep and a plug mountain', of which the second Switching device J; and the second terminal and the second terminal described above as the w-th capacitor is connected to the first node because the __ terminal is electrically connected to the second m (DC) loop current. The punishment "makes its second terminal connected to the eighth inductor described in the second above and the fourth-terminal of the second switching device to the seventh inductor. "Connected at the second Lang point 1 5. If the scope of the patent application has the ninth ... and the second + two wave-isolator circuit, more package-end ... sensors, of which the ninth inductor makes the first-known in other words The first node is connected to the eighth, the second terminal is connected to the aforementioned seventh inductor, and the first terminal of the seventh inductor is connected to the aforementioned first heart: the road, and the tenth inductor is crying. The eighth electricity of the beloved Lord :: and its second end is connected to the aforementioned second resonance circuit. = Please refer to the impedance range of the 15th item of the patent. The first switching device in H includes the first- The cymbal switch and the aforementioned second switching device includes a second cymbal switch. ] This brother] For example, if you apply for the impedance blocking waver circuit of item 16 of the patent scope, the aforementioned first winding of the aforementioned first spectrum vibration circuit, and the aforementioned second winding of the aforementioned first vibration-enhancing circuit. The wires, the aforementioned first reed switch, and the aforementioned second reed are arranged in a double-wound inductor structure. 18. The impedance-blocking chirper circuit according to item 16 of the scope of patent application, wherein the aforementioned first winding of the aforementioned -spectrum oscillator circuit and the aforementioned -reed switch are provided with a first current sensing unit, the aforementioned The aforementioned second winding of the second resonance circuit and the aforementioned second reed opening are equipped with 474085 A8 B8 C8 D8. 6. The second current sensing unit in the scope of patent application. 19 · The impedance blocking filter circuit according to item 10 of the patent application scope further includes a metal-oxygen variable resistor connected in series with the aforementioned capacitor and connected in parallel with the aforementioned first switching device. 2 0. The impedance blocking filter circuit according to item 10 of the patent application scope further includes a series connection with the aforementioned first, second and third inductors. Fuse 0 ------------ ----- (Please read the precautions on the back before filling this page) Order: • Line 'Printed by the Intellectual Property Bureau Staff Consumer Cooperatives of the Ministry of Economic Affairs This paper is printed in accordance with China National Standard (CNS) A4 (210 X 297) %) 31 91620