阅读说明：本技术 一种同轴开关模块及其构成的同轴扫描开关 (Coaxial switch module and coaxial scanning switch formed by same ) 是由 钱璐帅 富雅琼 于 2020-07-10 设计创作，主要内容包括：本发明涉及一种同轴开关模块及其构成的同轴扫描开关,包括柔性电路板、金属屏蔽盒、继电器阵列、继电器驱动器、固定座、同轴端子阵列、绝缘片；柔性电路板一端安装在金属屏蔽盒内部,另一端延伸至金属屏蔽盒外部；继电器阵列和继电器驱动器安装在金属屏蔽盒内部的柔性电路板上；同轴端子阵列包括一个公共同轴端子和多个通道同轴端子,所有同轴端子均穿过绝缘片后安装在金属屏蔽盒的外表面；公共同轴端子与多个通道同轴端子之间通过继电器阵列实现导通和断开；通过本发明可以解决精密交流信号、射频信号计量检定自动通道切换的问题,提高了相关计量检定业务的精度和效率。(The invention relates to a coaxial switch module and a coaxial scanning switch formed by the same, comprising a flexible circuit board, a metal shielding box, a relay array, a relay driver, a fixed seat, a coaxial terminal array and an insulating sheet; one end of the flexible circuit board is arranged inside the metal shielding box, and the other end of the flexible circuit board extends to the outside of the metal shielding box; the relay array and the relay driver are arranged on a flexible circuit board inside the metal shielding box; the coaxial terminal array comprises a common coaxial terminal and a plurality of channel coaxial terminals, and all the coaxial terminals penetrate through the insulating sheet and then are installed on the outer surface of the metal shielding box; the common coaxial terminal and the plurality of channel coaxial terminals are connected and disconnected through the relay array; the invention can solve the problem of automatic channel switching of metrological verification of precise alternating current signals and radio frequency signals, and improves the precision and efficiency of related metrological verification services.)

1. A coaxial switch module, characterized by: the relay driver comprises a flexible circuit board, a metal shielding box, a relay array, a relay driver, a fixed seat, a coaxial terminal array and an insulating sheet;

one end of the flexible circuit board is mounted inside the metal shielding box, and the other end of the flexible circuit board extends to the outside of the metal shielding box;

the relay array comprises a plurality of relays, the relays are installed inside the metal shielding box through the fixing seats, and signal pins of the relays are welded on the flexible circuit board inside the metal shielding box;

the relay driver is mounted on the flexible circuit board inside the metal shielding box;

the coaxial terminal array comprises a common coaxial terminal and a plurality of channel coaxial terminals; the common coaxial terminal and the plurality of channel coaxial terminals are installed on the outer surface of the metal shielding box after penetrating through the insulation sheet; the signal pins of the common coaxial terminal and the channel coaxial terminal penetrate through the metal shielding box and then are welded on the flexible circuit board in the metal shielding box; and the common coaxial terminal and the plurality of channel coaxial terminals are switched on and off through the relay array.

2. A coaxial switch module according to claim 1, wherein: the relay is a magnetic latching relay and is provided with a closing control coil, an opening control coil, a first switch and a second switch which act synchronously; the relay is of a normally open type, a normally closed type or a switching type.

3. A coaxial switch module according to claim 2, wherein: the movable contacts of all the relay first switches in the relay array are electrically connected with the core wire of the common coaxial terminal after being connected in parallel through the flexible circuit board, and the movable contacts of all the relay second switches in the relay array are electrically connected with the shielding wire of the common coaxial terminal after being connected in parallel through the flexible circuit board; and the static contact of the first switch of each relay of the relay array and the static contact of the second switch are correspondingly connected with the core wire and the shielding wire of each channel coaxial terminal, and metal wires which are parallel to the metal wires and connected with the same coaxial terminal shielding wire are arranged on two sides of all the metal wires connected with the core wires of the coaxial terminals on the flexible circuit board.

4. A coaxial switch module according to claim 1, wherein: the relay driver is a Darlington tube, a triode, a field effect tube or a special chip for relay driving.

5. A coaxial switch module according to claim 1, wherein: the metal shielding box comprises a bottom box and a cover plate, wherein a linear groove is formed in the bottom box, a linear protrusion is arranged on the cover plate, and the linear protrusion of the cover plate is matched with the linear groove in the bottom box.

6. A coaxial switch module according to claim 1 or 5, characterized in that: the inside baffle that is provided with of metal shielding box, the baffle will metal shielding box cuts apart into two regions, the relay array with the relay driver is installed respectively in two regions.

7. A coaxial switch module according to claim 1, wherein: the relay array is composed of N relays, the channel coaxial terminals are composed of N coaxial terminals, and the number of N is larger than or equal to 2.

8. A coaxial scanning switch, characterized by: the coaxial switch module comprises a coaxial cable, a signal transfer circuit board, a main controller, a fixed bracket and a plurality of coaxial switch modules according to any one of claims 1-7;

the plurality of coaxial switch modules are installed in the fixed support, and a common coaxial terminal of any one coaxial switch module is connected with any channel coaxial terminal of another coaxial switch module through the coaxial cable;

the signal switching circuit board is respectively connected with one end of a flexible circuit board, extending to the outside of the metal shielding box, of the coaxial switch modules, and is used for receiving control signals and distributing the control signals to each flexible circuit board interface according to a fixed sequence so as to control corresponding actions of the relay array corresponding to the coaxial switch modules;

the main controller is connected with the signal switching circuit board and then installed on the fixed support, and the main controller is used for providing control signals and controlling corresponding actions of the relays of the coaxial switch modules.

9. A coaxial scanning switch according to claim 8, wherein: a plurality of coaxial scanning switches are cascaded together to form a two-wire system single-channel multi-channel or four-wire system single-channel multi-channel coaxial scanning switch.

10. A coaxial scanning switch according to claim 8, wherein: the main control unit further comprises an automatic detection module and a human-computer interaction interface, the automatic detection module is used for detecting and judging the number and the position of the coaxial switch modules connected on the signal transfer circuit board, the human-computer interaction interface is used for converting man-made control intentions into electric signals, and the electric signals are translated by the main control unit to generate control signals and are transmitted to the signal transfer circuit board to control the action of the relay array of the corresponding coaxial switch modules.

Technical Field

The invention relates to the field of measurement and test, in particular to a coaxial switch module and a coaxial scanning switch formed by the same.

Background

With the continuous development and application of measurement technology, communication technology and computer technology, metering detection has gradually realized automatic measurement. The scanning switch is an instrument for constructing an electrical and thermal automatic metrological verification system, plays an important role in automatic measurement, and can enable one group of output (or input) signal channels to be switched among different groups of input (or output) signal channels under the control of operation panel input or program instructions.

At present, the existing commercial scan switch is generally developed aiming at the requirement of direct current measurement testing, and mainly adopts a relay or a multi-path waveband switch to realize the electrical switching between different input channels and a common output channel. Because the internal lead wire and the external lead wire of the scanning switch are in a non-shielding state and are easily subjected to electromagnetic interference between the inside and the outside of the scanning switch and other parts, the scanning switch is not suitable for measuring precise alternating current signals, especially high-frequency radio-frequency signals. At present, the measurement of precise alternating current signals is generally realized in a mode of manually switching coaxial cables, and an automatic test system cannot be constructed, so that the improvement of the metering test efficiency is limited.

In summary, it is necessary to provide a new scheme, which can solve the problem of automatic channel switching in high-precision ac signal metrological verification, avoid electromagnetic interference caused by external factors, and improve the efficiency of related metrological verification services.

Disclosure of Invention

Aiming at the problems, the invention provides a coaxial switch module and a coaxial scanning switch formed by the same, wherein a metal shielding box and a coaxial cable are adopted to shield a precise alternating current signal in a full path in a transmission process, and a precise alternating current signal verification channel can be automatically switched; the electromagnetic interference between the internal part and other external parts is avoided, and the detection precision of the precise alternating current signal and the efficiency of the metrological verification service are improved.

The invention provides a coaxial switch module, which comprises a flexible circuit board, a metal shielding box, a relay array, a relay driver, a fixed seat, a coaxial terminal array and an insulating sheet, wherein the flexible circuit board is arranged on the flexible circuit board;

one end of the flexible circuit board is mounted inside the metal shielding box, and the other end of the flexible circuit board extends to the outside of the metal shielding box;

the relay array comprises a plurality of relays, the relays are installed inside the metal shielding box through the fixing seats, and signal pins of the relays are welded on the flexible circuit board inside the metal shielding box;

the relay driver is mounted on the flexible circuit board inside the metal shielding box;

the coaxial terminal array comprises a common coaxial terminal and a plurality of channel coaxial terminals; the common coaxial terminal and the plurality of channel coaxial terminals are installed on the outer surface of the metal shielding box after penetrating through the insulation sheet; the signal pins of the common coaxial terminal and the channel coaxial terminal penetrate through the metal shielding box and then are welded on the flexible circuit board in the metal shielding box; and the common coaxial terminal and the plurality of channel coaxial terminals are switched on and off through the relay array.

Preferably, the relay is a magnetic latching relay, and is provided with a closing control coil, an opening control coil, a first switch and a second switch which act synchronously; the relay is of a normally open type, a normally closed type or a switching type.

Preferably, the movable contacts of all the first relay switches in the relay array are electrically connected with the core wire of the common coaxial terminal after being connected in parallel through the flexible circuit board, and the movable contacts of all the second relay switches in the relay array are electrically connected with the shielding wire of the common coaxial terminal after being connected in parallel through the flexible circuit board; and the static contact of the first switch of each relay of the relay array and the static contact of the second switch are correspondingly connected with the core wire and the shielding wire of each channel coaxial terminal, and metal wires which are parallel to the metal wires and connected with the same coaxial terminal shielding wire are arranged on two sides of all the metal wires connected with the core wires of the coaxial terminals on the flexible circuit board.

Preferably, the relay driver is a Darlington tube, a triode, a field effect tube or a special chip for relay driving.

Preferably, the metal shielding box comprises a bottom box and a cover plate, wherein a linear groove is formed in the bottom box, a linear protrusion is formed in the cover plate, and the linear protrusion of the cover plate is matched with the linear groove in the bottom box.

Preferably, a partition board is arranged inside the metal shielding box, the metal shielding box is divided into two regions by the partition board, and the relay array and the relay driver are respectively installed in the two regions.

Preferably, the relay array is composed of N relays, the plurality of channel coaxial terminals are composed of N coaxial terminals, and the number of N is greater than or equal to 2.

The invention also provides a coaxial scanning switch, which comprises a coaxial cable, a signal transfer circuit board, a main controller, a fixed support and a plurality of coaxial switch modules;

the plurality of coaxial switch modules are installed in the fixed support, and a common coaxial terminal of any one coaxial switch module is connected with any channel coaxial terminal of another coaxial switch module through the coaxial cable;

the signal switching circuit board is connected with one end of a flexible circuit board, extending to the outside of the metal shielding box, of the coaxial switch modules, and is used for receiving control signals and distributing the control signals to the interfaces of the flexible circuit board according to a fixed sequence so as to control corresponding actions of the relay array corresponding to the coaxial switch modules;

the main controller is connected with the signal switching circuit board and then installed on the fixed support, and the main controller is used for providing control signals and controlling corresponding actions of the relays of the coaxial switch modules.

Preferably, a plurality of coaxial scanning switches are cascaded together, and a two-wire one-way multichannel or four-wire one-way multichannel coaxial scanning switch can be formed.

Preferably, the main control unit further comprises an automatic detection module and a human-computer interaction interface, wherein the automatic detection module is used for detecting and judging the number and the position of the coaxial switch modules connected to the signal transfer circuit board, the human-computer interaction interface is used for converting man-made control will into electric signals, and the electric signals are translated by the main control unit to generate control signals and transmit the control signals to the signal transfer circuit board to control the action of the relay array of the corresponding coaxial switch modules.

The invention has the beneficial effects that:

1. the invention adopts the scheme of the metal shielding box and the coaxial cable to shield the precise alternating current signal in a full path from the input end to the output end, thereby avoiding the electromagnetic interference between the inside and other external parts and improving the precision of the metering and verification of the precise alternating current signal and the radio frequency signal.

2. The invention realizes automatic switching from different input (output) ends to different output (input) ends by controlling the action of the relay array, and improves the metering verification efficiency of precise alternating current signals and radio frequency signals.

Drawings

Fig. 1 is a schematic diagram of the overall structure of a coaxial switch module;

fig. 2 is an exploded view of a coaxial switch module configuration;

FIG. 3 is a schematic view of the internal structure of the metal shielding case;

FIG. 4 is a schematic diagram of the position of the coaxial terminal array, the relay array and the relay driver installed on the flexible circuit board;

FIG. 5 is a schematic diagram of an overall structure of a coaxial scanning switch;

FIG. 6 is a schematic diagram of a specific connection mode between the main controller and the signal adapter circuit board;

fig. 7 is a schematic structural diagram of a coaxial scanning switch formed by fifteen coaxial switch modules according to an embodiment;

fig. 8 is a schematic structural diagram of a specific embodiment of a two-wire single-channel multi-channel coaxial scanning switch;

in the figure: 1: a coaxial switch module; 2: a signal transfer circuit board; 3: a main controller; 4: fixing a bracket; 11: an array of coaxial terminals; 12: an insulating sheet; 13: a relay array; 14: a relay driver; 15: a flexible circuit board; 16: a fixed seat; 17: a metal shield case; 18: a first coaxial switch module; 19: a second coaxial switch module; 20: a fifteenth coaxial switch module; 21: a human-computer interaction interface; 111: a first channel coaxial terminal; 112: a common coaxial terminal; 113: a second channel coaxial terminal; 171: a bottom case; 172: a cover plate; 1711: a linear groove; 1721: linear protrusions;

Detailed Description

The present invention will be described in detail with reference to the specific embodiments shown in the drawings, which are not intended to limit the present invention, and structural, methodological, or functional changes made by those skilled in the art according to the specific embodiments are included in the scope of the present invention.

As shown in fig. 1 and 2, a coaxial switch module includes a flexible circuit board 15, a metal shielding box 17, a relay array 13, a relay driver 14, a fixing base 16, a coaxial terminal array 11, and an insulating sheet 12;

one end of the flexible circuit board 15 is installed inside the metal shielding box 17, and the other end extends to the outside of the metal shielding box 17;

as shown in fig. 3 and 4, the relay array 13 includes a plurality of relays, the plurality of relays are mounted inside a metal shielding box 17 through a fixing base 16, and signal pins of the plurality of relays are soldered on a flexible circuit board 15 inside the metal shielding box 17;

in a preferred embodiment, the relays in the relay array 13 are magnetic latching relays, each of which has a close control coil, an open control coil, and a first switch and a second switch that act synchronously, and the relays may be of a normally open type, a normally closed type, or a switching type;

in order to provide more choices for users, the core wire and the shield wire of the coaxial terminal can be respectively connected with the signal pin of the relay; the movable contact of the relay first switch in the relay array 13 is electrically connected with the core wire of the common coaxial terminal after being connected in parallel through the flexible circuit board 15, and the movable contact of the relay second switch in the relay array 13 is electrically connected with the shielding wire of the common coaxial terminal after being connected in parallel through the flexible circuit board 15; the static contact of the first switch of each relay of the relay array and the static contact of the second switch are correspondingly connected with the core wire and the shielding wire of each channel coaxial terminal, and on the flexible circuit board 15, both sides of all metal conducting wires connected with the core wires of the coaxial terminals are provided with conducting wires which are parallel to the metal conducting wires and connected with the shielding wire of the same coaxial terminal.

As shown in fig. 4, the relay driver 14 is mounted on the flexible circuit board 15 inside the metal shield case 17; in a preferred embodiment, the relay driver 14 is a darlington transistor, a triode, a field effect transistor, or a chip dedicated to relay driving.

As shown in fig. 2, the coaxial terminal array 11 includes one common coaxial terminal and a plurality of via coaxial terminals; the common coaxial terminal and the plurality of channel coaxial terminals are installed on the outer surface of the metal shielding box 17 after penetrating through the insulation sheet 12; the signal pins of the common coaxial terminal and the multiple channel coaxial terminals pass through the metal shielding box 17 and then are welded on the flexible circuit board 15 in the metal shielding box 17; the common coaxial terminal and the plurality of channel coaxial terminals are turned on and off by the relay array 13.

In order to make the coaxial switch modules closely connected when they are placed side by side, there is a preferred scheme that the metal shielding box 17 includes a bottom box 171 and a cover plate 172, a linear groove 1711 is provided on the bottom box 171, a linear protrusion 1721 is provided on the cover plate 172, and the linear protrusion 1721 of the cover plate is installed after matching with the linear groove 1711 on the bottom box.

To avoid interference of the switched precision ac and rf signals by heat and electromagnetic disturbances generated by the relay driver 14 during operation. Preferably, as shown in fig. 3 and 4, a partition is provided inside the metal shield case 17, and the partition divides the metal shield case 17 into two regions in which the relay array 13 and the relay driver 14 are installed, respectively.

The relay array 13 is composed of N relays, the plurality of channel coaxial terminals are composed of N coaxial terminals, and the number of N is more than or equal to 2;

the relay array 13 has at least two relays, and the coaxial terminal array 11 has a common coaxial terminal and at least two channel coaxial terminals, so that a coaxial switch module with a plurality of input ports connected to one output port can be formed, and multi-path precise alternating current signals can be switched to the same output port for output. At any moment, at most one relay is in a closed state, the other relays are in an open state, and at the moment, the core wire and the shielding wire of the channel coaxial terminal connected with the closed relay are respectively connected with the core wire and the shielding wire of the common coaxial terminal. In summary, by closing different relays, the electrical connection between the coaxial terminals of different channels and the common coaxial terminal can be realized, and at the same time, a good signal shielding effect can be maintained.

As shown in fig. 5, a coaxial scanning switch includes a coaxial cable, a signal adapting circuit board 2, a main controller, a fixing bracket 4, and a plurality of coaxial switch modules 1 as described above; note that the coaxial cable and the main controller are omitted in fig. 5.

A plurality of coaxial switch modules 1 are arranged in a fixed bracket 4, and a common coaxial terminal of one coaxial switch module 1 is connected with any channel coaxial terminal of another coaxial switch module 1 through a coaxial cable;

the signal switching circuit board 2 is respectively connected with one end of the flexible circuit board, extending to the outside of the metal shielding box, of the coaxial switch modules 1, and is used for receiving control signals and distributing the control signals to each flexible circuit board interface according to a fixed sequence so as to control the relay of the corresponding coaxial switch module 1 to act;

in a specific embodiment, the signal transfer circuit board 2 includes a control signal input port, a control signal output port, and a plurality of flexible circuit board interfaces, and the control signal input from the control signal input port is distributed to each flexible circuit board interface according to a fixed sequence, so as to control the action of the relay array of the corresponding coaxial switch module; the control signal input from the control signal input port is completely copied to the control signal output port.

It should be noted that, a plurality of signal adapting circuit boards 2 may be connected in series, for example, the control signal output port of the first signal adapting board is correspondingly connected with the control signal input port of the second signal adapting circuit board; the control signal synchronization of the first signal switching circuit board and the second signal switching circuit board can be realized, so that when a plurality of coaxial scanning switches are cascaded, the control signal simultaneously controls the plurality of coaxial scanning switches which are cascaded together, corresponding coaxial switch modules in the coaxial scanning switches synchronously act, and the required switching of one or more pairs of coaxial channels can be realized.

The main controller is connected with the signal transfer circuit board 2 and then installed on the fixed support 4, and the main controller is used for providing control signals and controlling corresponding actions of the relays of the coaxial switch modules.

In a preferred embodiment, as shown in fig. 6, the main controller 3 is connected to the signal relay circuit board 2 and then mounted on the signal relay circuit board 2. It should be noted that the specific connection form between the main controller 3 and the signal relay circuit board 2 and the specific installation position of the main controller 3 are not limited to those shown in fig. 6.

The main controller 3 further comprises an automatic detection module and a human-computer interaction interface 21, wherein the automatic detection module is used for detecting and judging the number and the positions of the coaxial switch modules connected to the signal transfer circuit board 2, and the human-computer interaction interface 21 is connected with the main controller 3 through a connecting wire; the relay is used for converting man-made control will into electric signals, the electric signals are translated through the main controller 3 to generate control signals, the control signals are transmitted to the signal transfer circuit board 2, and actions of the relay of the corresponding coaxial switch module are controlled.

The main controller 3 further comprises a control signal output port, the control signal output port is correspondingly connected with a control signal input port of the signal transfer circuit board 2, the human-computer interaction interface 21 is used for converting human control will into electric signals, the electric signals are translated by the main controller to generate control signals, the control signals are transmitted to the control signal input port of the signal transfer circuit board 2 through the control signal output port, the control signals input from the control signal input port are distributed to all flexible circuit board interfaces according to a fixed sequence, and then actions of the relay array corresponding to the coaxial switch module are controlled.

The embodiment of the present invention will be described by taking a coaxial scanning switch composed of fifteen coaxial mold opening blocks as an example:

as shown in fig. 7, the coaxial switch module includes a common coaxial terminal 112, a first channel coaxial terminal 111, a second channel coaxial terminal 113, a relay No. one and a relay No. two; the first relay and the second relay respectively comprise a first switch and a second switch;

the movable contacts of the first switches of the first relay and the second relay are connected in parallel through the flexible circuit board and then are connected with the core wire of the common coaxial terminal 112; the movable contacts of the first relay and the second relay second switch are connected in parallel through the flexible circuit board and then are connected with the shielding wire of the common coaxial terminal 112; the stationary contact of the first switch of the first relay is connected with the core wire of the first channel coaxial terminal 111 through the flexible circuit board; the stationary contact of the second switch of the first relay is connected with the shielding wire of the first channel coaxial terminal 111 through the flexible circuit board; the stationary contact of the first switch of the second relay is connected with the core wire of the second channel coaxial terminal 113 through the flexible circuit board; the stationary contacts of the second switch of the second relay are connected to each other through the flexible circuit board and the shield wire of the second channel coaxial terminal 113.

When the coaxial switch module is used, the first relay is closed, and the first channel coaxial terminal 111 and the common coaxial terminal 112 are connected with each other; if the relay No. two is closed, the second channel coaxial terminal 113 and the common coaxial terminal 112 are connected to each other; if neither relay I nor relay II is closed, no channel coaxial terminal and common coaxial terminal are connected with each other. It should be noted that the relay # one and the relay # two are not allowed to be connected at the same time.

Fifteen coaxial switch modules are tightly connected together and are arranged in a fixed support 4, the tail part of a flexible circuit board is arranged on an interface of a signal transfer circuit board 2, and a coaxial scanning switch is formed by matching with a main controller (the main controller is omitted in figure 7); wherein, the coaxial switch module close to the fixed bracket 4 is a first coaxial switch module 18, the coaxial switch module close to the first coaxial switch module 18 is a second coaxial switch module 19, and so on, and the last coaxial switch module is a fifteenth coaxial switch module 20; the first channel coaxial terminal 111 in the first coaxial switch module 18 is connected to the common coaxial terminal 112 in the second coaxial switch module 19 by a coaxial cable, and the first channel coaxial terminal 111 in the second coaxial switch module 19 is connected to the common coaxial terminal 112 in the third coaxial switch module by a coaxial cable (the coaxial cable is omitted in fig. 7); and so on to complete the connection of all the coaxial switch modules;

the common coaxial terminal of the first coaxial switch module is a common output end of the scanning switch, and the channel coaxial terminals of all the other coaxial switch modules and the first coaxial switch module which are not connected with the coaxial cable are channel input ends of the coaxial scanning switch.

Taking the example that the input end of the channel in the fifth coaxial switch module is connected to the common output end as an example, it is only necessary to close the relay No. 1 in the first to fourth coaxial switch modules and close the relay No. 2 in the fifth coaxial switch module.

As shown in fig. 8, a plurality of coaxial scanning switches are cascaded together to form a two-wire single-channel multi-channel or four-wire single-channel multi-channel coaxial scanning switch; two coaxial scanning switches are cascaded together to form a two-wire system single-channel multi-channel coaxial scanning switch as an example for description; note that the coaxial cable is omitted in fig. 8.

The two coaxial scanning switches are cascaded together, and a control signal output port of the first signal transfer circuit board is correspondingly connected with a control signal input port of the second signal transfer circuit board. Thus, the control signal provided by the main controller can be transmitted to the first signal transfer circuit board and the second signal transfer circuit board simultaneously; at this time, the first and second coaxial scanning switches will act synchronously, so that the required two-wire system single-channel multi-channel signal can be automatically switched.

The invention adopts the scheme of the metal shielding box and the coaxial cable to shield the precise alternating current signals from the input end to the output end in a full path, avoids the electromagnetic interference between the inside and other external components, improves the precision of the metering verification of the precise alternating current signals and the radio frequency signals, realizes the automatic switching of different input (output) ends to the output (input) ends by controlling the action of the relay array, and improves the efficiency of the metering verification of the precise alternating current signals and the radio frequency signals.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.