CN100442059C - Apparatus and method for isolating input channels in electronic testing instrument - Google Patents
Apparatus and method for isolating input channels in electronic testing instrument Download PDFInfo
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- CN100442059C CN100442059C CNB2004100951681A CN200410095168A CN100442059C CN 100442059 C CN100442059 C CN 100442059C CN B2004100951681 A CNB2004100951681 A CN B2004100951681A CN 200410095168 A CN200410095168 A CN 200410095168A CN 100442059 C CN100442059 C CN 100442059C
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Abstract
The present invention relates to an apparatus and a method for isolating input channels in an electronic testing instrument for an electric isolating instrument, wherein frequency mix is carried out on signals to be electrically isolated through a multiplier and carrier signals for generating modulated carrier signals. The modulated carrier signals pass through an isolation barrier; then, the modulated carrier signals are demodulated and filtered for extracting original input signals.
Description
Technical field:
Present invention relates in general to signal analysis device, especially relate to a kind of equipment that is used to provide the electricity isolation, for example, the electricity between signal of testing (SUT) and the electronic test equipment is isolated.
Background technology:
Signal acquisition apparatus or test and measuring equipment be digital storage oscilloscope (DSOs) and similar devices for example, receives one or more signals of testing (SUT) by one or more input channels separately.Input channel electrically isolated from one and with the isolated chassis ground of test and measuring equipment be very important.For the signal of the frequency with the bandwidth from DC to the measuring equipment, such isolation is essential.Such isolation allows a plurality of signals of testing are offered measuring equipment, and by identical measuring equipment a plurality of signals of testing is analyzed, and can system/signal of testing not impacted.
A kind of for a person skilled in the art known partition method that is applied in the broadband system is so-called " binary channels scheme ", and wherein, input signal is divided into two signals; That is, a low-frequency input signal and a high-frequency input signal.Photo-coupler is used for low frequency signal (for example signal under 1MHz), and wide-band transformer is used to high-frequency signal.Regrettably, the linearization of photo-coupler implements both difficult and expensive, and the wide-band linearity transformer is also very expensive.In addition, the low side high-frequency signal composition of the isolation of the measured signal that very difficult assurance draws can mate fully fully, makes their recombinants to be suitable for by test and further " smoothly " signal handled of measuring equipment with generation.
Summary of the invention:
Proposed these and other deficiencies of the prior art in the present invention, the equipment among the present invention adopts the mode of avoiding " binary channels scheme " and its intrinsic difficulty that broadband signal is isolated.Comprise electric isolated device (isolator) in one embodiment, wherein, signal and carrier signal mixing that multiplier will be isolated by electricity, to produce modulated carrier signal, this modulated carrier signal is separated mediation filtering then, thereby is extracted original input signal through isolation barrier.
In one embodiment, the present invention is suitable for a kind of equipment, and this equipment comprises modulator, is used for input signal is modulated to carrier signal, thereby produces modulated carrier signal, and this modulated carrier signal has the first associated ground connection benchmark; Xegregating unit is used to handle this modulation signal to produce corresponding modulation signal, and this modulation signal has the second associated ground connection benchmark; Detuner, thus be used for corresponding modulation signal of demodulation and corresponding carrier signal generation demodulated signal; And wave filter, be used for recovering respective input signals from demodulated signal.
Description of drawings
Instruction of the present invention can be understood easily by the detailed description of doing below in conjunction with accompanying drawing, wherein
Fig. 1 has described the high-level block diagram of signal isolation system according to an embodiment of the invention;
Fig. 2 has described the process flow diagram of method according to an embodiment of the invention;
Fig. 3-6 usefulness chart has been described several oscillograms of the present invention that help to understand.
For the ease of understanding, adopt identical Reference numeral to indicate the common identical parts that adopt in the accompanying drawing.
Embodiment
The present invention at first is described in the scope of test and measuring equipment, for example digital storage oscilloscope, analog oscilloscope and similar equipment.Yet the those skilled in the art can be appreciated that in any environment that the present invention can be applied to advantageously to expect that the electricity of quite wide bandwidth signal isolates.
Fig. 1 describes the high-level block diagram of signal isolation system according to an embodiment of the invention.Especially, the system 100 among Fig. 1 comprises first impact damper 105, the first active (active) frequency mixer, 110, the first isolators, 120, the second isolators, 130, the second active mixer 140, the second impact dampers 145, oscillator 150 and wave filters 160.It should be noted that first impact damper 105, first active mixer 110 and second active mixer 140, second impact damper 145, oscillator 150 and wave filter 160 electricity are mutually isolated.
Differential input signal is cushioned by first impact damper 105, and is coupled to first active mixer 110.The operation of first active mixer 110 is multiplied each other with the differential input signal that will be cushioned and first carrier signal CARRIER or modulate, with generation modulated signal MOD.This modulated signal MOD is sent to the importation of second isolator 130.Last second active mixer 140 that is coupled to by isolation signals that produces from the efferent branch of second isolator 130.
Second active mixer 140 receives the second carrier signal CARRIER`, this signal identical with the first carrier signal CARRIER that is provided to first active mixer 110 in fact (although isolating with it).The work of second active mixer 140 has been isolated with demodulation and the differential input signal modulate also produces demodulation differential signal DEMOD thus.
Demodulation differential signal DEMOD is coupled to wave filter 160 via second impact damper 145.Wave filter 160 work to be carrying out smothing filtering to demodulated differential signal DEMOD, and produces a differential output signal thus, and it has the characteristics of signals similar substantially with the characteristics of signals of differential input signal.
In one embodiment of the invention, each impact damper 105,145 comprises modules A D8131 impact damper and modules A D8343 active mixer, and these modules all are to be made by the analog machine company limited of the Nuo Wude that is positioned at the Massachusetts.First isolator 120 and second isolator 130 can comprise each pulse transformer as modules A 6801 transformers packaging together, are provided by the pulse engineering company limited in the Santiago that is positioned at California.First isolator 120 and second isolator 130 can also include linear photo-coupler, and low-power consumption radio frequency (RF) emittor/receiver is to (just antenna and corresponding circuit), fiber plant and similar devices.It should be noted that the frequency that needs to isolate is very high comparatively speaking, therefore, the optical isolation devices that resembles the linear optocoupler of working range below DC is unnecessary, even this kind equipment can use within the scope of the invention.Wave filter 160 can comprise Bessel filter, Gaussian filter, elliptic filter and other similar wave filter.
In one embodiment, oscillator 150 comprises an oscillator that produces the 242.42MHz of square wave, and wave filter comprises the 5 rank low pass Bessel filters of a 200MHz, and first isolator 120 and second isolator 130 comprise pulse transformer.In this embodiment, the work of first active mixer 110 with by with ± 1 and differential input signal multiply each other differential input signal modulated (just carrier signal being carried out convolution operation).Utilize this mode, the signal MOD that first active mixer 110 produces includes the differential input signal that is multiplied each other by square wave by for example conversion operations.In this embodiment, the signal of having been isolated and having modulated that obtains by convolution by second isolator with synchronous demodulation of second active mixer 140 work.
Fig. 2 has described the process flow diagram of method according to an embodiment of the invention.When being modulated to input signal on the carrier signal, the method 200 of Fig. 2 enters into step 210 when modulator (for example, first active mixer 110).With reference to square frame 215, carrier signal can comprise a sine wave, square wave, sawtooth wave or other waveform.
In step 220, adopt xegregating unit (for example, second isolator 130) will be coupled to detuner (for example, second active mixer 140) through the signal of ovennodulation.With reference to square frame 225, xegregating unit can comprise a transformer, photo-coupler, or other xegregating unit.Xegregating unit is to be used to guarantee the ground connection benchmark relevant with input signal can float with respect to the ground connection benchmark relevant with subsequently output signal (float).
In step 230, adopt a corresponding carrier signal that the isolation signals that receives from xegregating unit is carried out demodulation.With reference to square frame 235, according to the modulation scheme type that first active mixer uses, the detuner (that is, second active mixer 140) that is used to carry out this task can comprise balanced mixer, non-balanced frequency mixers, demoder or other equipment that is fit to.
In step 240, filtering or smoothing solution tonal signal are to recover input signal.With reference to square frame 245, the filtering of use or smooth function may comprise the Bezier filter function, gaussian filtering function, oval filter function or other suitable filter function.
Fig. 3 has described several waveforms of the present invention that help to understand with chart, especially, Fig. 3 A has described when using sinusoidal carrier signal and frequency input signal to be lower than frequency of carrier signal, the waveform of the modulated signal MOD that is produced by first active mixer 110 (as balanced mixer) shows the output signal MOD that is produced by first active mixer 110.Fig. 3 B has described a waveform, is used for the signal DEMOD of diagram by the demodulation of second active mixer 140 (carrying out work as balanced mixer) generation.Fig. 3 C has described the differential output signal that wave filter 160 produces.For reference purpose, Fig. 3 A, 3B, each among the 3C all shows input signal and the actual signal on this aspect of describing.
Fig. 4 has described several waveforms of the present invention that help to understand with chart.Especially, Fig. 4 A has described the waveform faster than the signal MOD of the modulation under half the situation in carrier signal cycle in rise time of user's wave carrier signal signal and input signal.The restituted signal DEMOD that Fig. 4 B has described being produced by second active mixer carries out graphic waveform.It should be noted that this restituted signal comprises original input signal in fact, and the short-time pulse waveform that this original input signal has several high speeds disturbs 410,420, this short-time pulse waveform disturbs 410,420th, joins in the input signal in modulated process.It should be noted that owing to used the square wave carrier signal, this short-time pulse waveform disturbs 410,420 to compare with carrier signal with input signal and to have very high frequency.Owing to this reason, simplified the realization of wave filter 160.Fig. 4 C has described an output signal that is produced by wave filter 160.For the purpose of reference, Fig. 4 A, 4B, each among the 4C all shows an input signal and the actual signal on this aspect of describing.
With reference to figure 4A, should be noted that input signal has an initial rising edge, it occurs in the center section of square wave carrier signal rather than at the transition portion of square-wave signal.Notice that it is very important that square-wave frequency modulation can be caught all basically phase place/temporal informations fully.Opposite, because sinusoidal wave edge has the bound comparatively speaking rise time, adopt sinusoidal carrier signal acquisition phase/temporal information accurately.The accompanying drawing of describing shows the advantage of square wave carrier signal with respect to sinusoidal wave carrier signal.Except the realization of having simplified wave filter 160, modulating/demodulating can also adopt the multiplication techniques (adopting sinusoidal wave carrier wave) of a switch technology rather than balance to carry out.
Fig. 5 adopts chart to describe several waveforms of the present invention that help to understand.Especially, Fig. 5 A has described the waveform that is slower than the modulation signal MOD under half the situation in carrier signal cycle in the rise time of user's wave carrier signal signal and input signal.Fig. 5 B has described the waveform of diagram by the restituted signal DEMOD of second active mixer, 140 generations.It should be noted that restituted signal has consisted essentially of original input signal, the short-time pulse waveform that this original input signal has several high speeds disturbs 510, and this short-time pulse waveform disturbs 510 to join input signal in modulated process.It should be noted that owing to used the square wave carrier signal, this short-time pulse waveform disturbs 510 to compare with carrier signal with input and to have very high frequency, thereby has simplified the realization of wave filter 160.Fig. 5 C has described the output signal that is produced by wave filter 160.For the purpose of reference, Fig. 5 A, 5B, each among the 5C all shows an input signal and the actual signal on this aspect of describing.
Fig. 6 has described several waveforms of the present invention that help to understand with chart.Especially, Fig. 6 A has described at user's wave carrier signal signal and input signal and has had waveform than the modulation signal MOD under the situation of carrier signal higher frequency.Fig. 6 B describes a waveform, and this waveform shows the restituted signal DEMOD that is produced by second active mixer 140.It should be noted that this restituted signal includes original input signal in fact, the short-time pulse waveform that this original input signal has several high speeds disturbs 610, and they join input signal in modulated process.Fig. 6 C has been provided by the output signal that is provided by wave filter 160.For reference purpose, Fig. 6 A, 6B, each among the 6C all shows an input signal and the actual signal on this aspect of describing.
Though aforesaid content has only related to the preferred embodiment that the present invention mentions, under the situation that does not break away from base region of the present invention, also can obtain other and more embodiment of the present invention, this base region is limited by claim subsequently.
Claims (10)
1, a kind of device comprises:
Modulator is used for input signal is modulated to carrier signal, and produces modulated carrier signal, and the described modulator and the first ground connection benchmark are coupled;
Detuner, be used to receive the representative of described modulated carrier signal and the representative of described carrier signal, thereby the described representative of demodulation modulated carrier signal is to produce the signal of demodulation, and the described detuner and the second ground connection benchmark are coupled, the mutual electrical isolation of the described first and second ground connection benchmark;
Isolator is used for receiving described modulated carrier signal from described modulator, produces the described representative of modulated carrier signal, and the described representative of modulated carrier signal is sent to described detuner, keeps the described isolation of the described first and second ground connection benchmark simultaneously; With
Wave filter is used for recovering respective input signals from described restituted signal.
2, equipment as claimed in claim 1, wherein said modulator comprises converter, this converter operation is multiplied each other input signal and ± 1 in response to carrier signal.
3, equipment as claimed in claim 1, wherein said modulator and demodulator includes balanced mixer.
4, equipment as claimed in claim 1, wherein said isolator comprises transformer.
5, equipment as claimed in claim 4, wherein said isolator comprise pulse transformer and described carrier signal comprises square wave, and the twice of the frequency of the described input signal of frequency ratio of described square wave is taller.
6, equipment as claimed in claim 1 further comprises:
Oscillator is used to produce described carrier signal, and one of described oscillator and described first and second ground connection benchmark are coupled, and the output terminal of described oscillator directly is coupled with one of described modulator and described detuner; With
Second isolator receives described carrier signal and the representative of described carrier signal is sent to another one in described modulator and the described detuner, the described isolation that keeps the first and second ground connection benchmark simultaneously.
7, equipment as claimed in claim 6, wherein:
Described first and second isolators comprise transformer.
8, equipment as claimed in claim 7, wherein:
The described representative of described carrier signal and described carrier signal comprises each square-wave signal with common preset frequency.
9, equipment as claimed in claim 8, wherein said preset frequency is lower than the frequency of input signal.
10, equipment as claimed in claim 1, wherein said wave filter comprise at least a in Bessel filter, Gaussian filter and the elliptic filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100951681A CN100442059C (en) | 2004-05-21 | 2004-05-21 | Apparatus and method for isolating input channels in electronic testing instrument |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2004100951681A CN100442059C (en) | 2004-05-21 | 2004-05-21 | Apparatus and method for isolating input channels in electronic testing instrument |
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| CN1700021A CN1700021A (en) | 2005-11-23 |
| CN100442059C true CN100442059C (en) | 2008-12-10 |
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| US8199149B2 (en) * | 2007-12-13 | 2012-06-12 | Tektronix, Inc. | Automatic generation of frequency domain mask |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4130743A (en) * | 1976-08-24 | 1978-12-19 | Compagnie Industrielle Des Telecommunications Cit-Alcatel | Terminal equipment for a multiplex carrier current telephone system |
| US5371760A (en) * | 1993-04-28 | 1994-12-06 | Telesis Technologies Laboratory | Method and apparatus for measuring the impulse response of a radio channel |
| CN1131481A (en) * | 1994-08-01 | 1996-09-18 | 摩托罗拉公司 | Line interface apparatus and method for isolating data terminal equipment from the line |
| CN1119011C (en) * | 1998-04-17 | 2003-08-20 | 汤姆森多媒体公司 | Modem containing device for detecting telephone line busy state |
-
2004
- 2004-05-21 CN CNB2004100951681A patent/CN100442059C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4130743A (en) * | 1976-08-24 | 1978-12-19 | Compagnie Industrielle Des Telecommunications Cit-Alcatel | Terminal equipment for a multiplex carrier current telephone system |
| US5371760A (en) * | 1993-04-28 | 1994-12-06 | Telesis Technologies Laboratory | Method and apparatus for measuring the impulse response of a radio channel |
| CN1131481A (en) * | 1994-08-01 | 1996-09-18 | 摩托罗拉公司 | Line interface apparatus and method for isolating data terminal equipment from the line |
| CN1119011C (en) * | 1998-04-17 | 2003-08-20 | 汤姆森多媒体公司 | Modem containing device for detecting telephone line busy state |
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Granted publication date: 20081210 Termination date: 20140521 |