Patent US3760198A successfully refreshed from Google Patents.
US3760198A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuitry for transmitting pulses with ground isolation but without pulse waveform distortion
Assignee: Yokogawa Electric Corp
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Filing: 1971-10-21
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Granted: 1973-09-18
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Expires: 1991-10-21
Abstract
Abstract A ground isolation circuit, capable of transferring signal pulses from a source device to a succeeding device operating at a different ground potential, is characterized by a distortion free transfer of the pulse waveform. Signal pulses at the source device are applied to the input winding of a pulse transformer to cause pulses to be induced across an isolated output winding of the transformer. The induced pulses, containing waveform sag distortion due to transformer inductance, are applied to an operational amplifier which includes a resistive-capative negative feedback circuit having its impedance parameters valued in relation to the impedance parameters of the pulse transformer to compensate by means of feedback for the pulse waveform sag introduced by the pulse transformer. The output of the operational amplifier is applied directly to the succeeding device or to a second isolation circuit adapted to eliminate distortion in pulses having a relatively long duration. In the second isolation circuit a pair of coincidence gates are each gated both by the output waveform of the operational amplifier and by an oscillator supplying opposite polarity clock pulses to the two gates, and thus the gate outputs are clock pulse trains of opposite polarity, occurring contemporaneously with the signal pulse. A second pulse transformer has its input winding connected to the gate outputs, to cause an alternating polarity waveform to be induced across an isolated output winding. This alternating waveform is rectified and applied to a switch to cause it to be ''''on'''' during the signal pulse. By selecting the clock pulse period to be short in relations to the signal pulse period, insignificant pulse waveform sag is introduced by the second pulse transformer, since each clock pulse restores the transformer output to its previous level, and the switch is accurately controlled.
Inventors
- 👤 H Mori
- 👤 Y Wakasa
- 👤 H Uchiike
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:04
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60; H03K17/601; H03K3/00; H03K3/02; H03K3/023; H03K3/0233; H03K3/02337
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
160 words
A ground isolation circuit for transferring signal pulses from a source device to a succeeding device with control of pulse waveform distortion, said circuit comprising: a pulse transformer having an input winding for receiving signal pulses from said source device and an output winding across which pulse waveforms are induced, the output winding being isolated from the input winding, the pulse transformer distorting the signal pulses by introducing waveform sag in the induced pulse waveforms, and compensating means connected to receive the distorted pulse waveforms induced in said output winding and arranged to supply its output waveform to said succeeding device, said compensating means including amplifier means with a capacitive negative feedback circuit, the feedback circuit having its impedance parameters valued in relation to the sag-introducing impedance parameters of said pulse transformer to selectively compensate by means of feedback for the pulse waveform sag introduced by said pulse transformer, thereby to provide a compensated output waveform with controlled waveform distortion.
Claim 2
Dependent Claim
160 words
A ground isolation circuit for transferring signal pulses from a source device to a succeeding device with control of pulse waveform distortion, said circuit comprising: a pulse transformer having an input winding for receiving signal pulses from said source device and an output winding across which pulse waveforms are induced, the output winding being isolated from the input winding, the pulse transformer distorting the signal pulses by introducing waveform sag in the induced pulse waveforms, and compensating means connected to receive the distorted pulse waveforms induced in said output winding and arranged to supply its output waveform to said succeeding device, said compensating means including amplifier means with a capacitive negative feedback circuit, the feedback circuit having its impedance parameters valued in relation to the sag-introducing impedance parameters of said pulse transformer to selectively compensate by means of feedback for the pulse waveform sag introduced by said pulse transformer, thereby to provide a compensated output waveform with controlled waveform distortion.
Claim 3
Dependent Claim
55 words
A ground isolation circuit for transferring signal pulses as claimed in claim 1 wherein said amplifier means is an operational amplifier and wherein said feedback circuit comprises a resistance and a capacitance in series having their impedance parameters matched with said transformer parameters to substantially fully compensate for pulse waveform sag introduced by said transformer.
Claim 4
Dependent Claim
70 words
A ground isolation circuit for transferring signal pulses as claimed in claim 1 wherein said amplifier means comprises an operational amplifier having its positive input terminal connected to the transformer output winding and its negative input terminal connected to the transformer output winding through a ground resistor R1, said feedback circuit including a series resistance R2 and capacitance C1 connected between the amplifier output terminal and its negative input terminal.
Claim 5
Dependent Claim
55 words
A ground isolation circuit for transferring signal pulses as claimed in claim 3 wherein the impedance parameters of said transformer define a time constant T1, and wherein the parameters of said compensation circuit are related thereto by the expression T1 C1(R1 + R2), whereby the waveform sag introduced by said transformer is substantially fully compensated.
Claim 6
Dependent Claim
57 words
A ground isolation circuit for transferring signal pulses as claimed in claim 3 wherein the impedance parameters of said transformer define a time constant T1, and wherein the parameters of impedance of said compensating means are related thereto by the expression T1 > C1 (R1 + R2), whereby the waveform sag introduced by said transformer is overcompensated.
Claim 7
Dependent Claim
30 words
A ground isolation circuit as claimed in claim 1 wherein said capacitive feedback circuit comprises impedances which are adjustable in value to adjust the compensation afforded by said compensating means.
Claim 8
Dependent Claim
37 words
A ground isolation circuit for transferring signal pulses as claimed in claim 6 wherein said feedback circuits include an adjustable resistance in parallel with a capacitance, thereby to permit the effective value of capacitance to be adjusted.
Claim 9
Dependent Claim
293 words
A ground isolation circuit for transferring signal pulses from a source device to a succeeding device with control of pulse waveform distortion, said circuit comprising: a pulse transformer having an input winding for receiving signal pulses from said source device and an output winding across which pulse waveforms are inducEd, the output winding being isolated from the input winding, compensating means connected to receive the pulse waveforms induced in said output winding and arranged to supply its output waveform to said succeeding device, said compensating means including amplifier means with a capacitive negative feedback circuit, the feedback circuit having its impedance parameters valued in relation to the impedance parameters of said pulse transformer to selectively compensate by means of feedback for pulse waveform sag introduced by said pulse transformer, thereby to provide a compensated output waveform with controlled waveform distortion, and an isolating circuit connected between the output of said compensating means and said succeeding device, said isolating circuit comprising: coincidence gate means gated through one input by the output waveform of said compensating means, oscillator means supplying a clock pulse to the other input of said gate means, a pulse transformer having its input winding connected to the output of said gate means, whereby said input winding receives an alternating signal for the duration of each of said signal pulses, said transformer having an isolated output winding across which a corresponding alternating waveform is induced, and switching means maintained in a preselected state by said induced alternating waveform, the output of said switching means being applied to said succeeding device, whereby said induced alternating waveform is substantially uniform in magnitude for the duration of each of said signal pulses to reliably control said switching means to provide a substantially distortionless output waveform.
Claim 10
Dependent Claim
293 words
A ground isolation circuit for transferring signal pulses from a source device to a succeeding device with control of pulse waveform distortion, said circuit comprising: a pulse transformer having an input winding for receiving signal pulses from said source device and an output winding across which pulse waveforms are inducEd, the output winding being isolated from the input winding, compensating means connected to receive the pulse waveforms induced in said output winding and arranged to supply its output waveform to said succeeding device, said compensating means including amplifier means with a capacitive negative feedback circuit, the feedback circuit having its impedance parameters valued in relation to the impedance parameters of said pulse transformer to selectively compensate by means of feedback for pulse waveform sag introduced by said pulse transformer, thereby to provide a compensated output waveform with controlled waveform distortion, and an isolating circuit connected between the output of said compensating means and said succeeding device, said isolating circuit comprising: coincidence gate means gated through one input by the output waveform of said compensating means, oscillator means supplying a clock pulse to the other input of said gate means, a pulse transformer having its input winding connected to the output of said gate means, whereby said input winding receives an alternating signal for the duration of each of said signal pulses, said transformer having an isolated output winding across which a corresponding alternating waveform is induced, and switching means maintained in a preselected state by said induced alternating waveform, the output of said switching means being applied to said succeeding device, whereby said induced alternating waveform is substantially uniform in magnitude for the duration of each of said signal pulses to reliably control said switching means to provide a substantially distortionless output waveform.
Claim 11
Dependent Claim
44 words
A ground isolation circuit for transferring signal pulses as claimed in claim 8 wherein said compensating means has its impedance parameters valued in relation to the impedance parameters of its pulse transformer so as to overcompensate for the sag introduced by its pulse transformer.
Claim 12
Dependent Claim
76 words
A ground isolation circuit for transferring pulses as claimed in claim 8 wherein said coincidence gate means comprises a pair of coincidence gates each receiving at one input the output waveform of said compensating means, said oscillator means comprising means for providing synchronous clock pulses of opposite polarity applied respectively to the remaining inputs of said pair of coincidence gates, said pulse transformer input winding being connected between the outputs of said pair of coincidence gates.
Claim 13
Dependent Claim
43 words
A ground isolation circuit for transferring pulses as claimed in claim 8 wherein said switching means comprises means for rectifying the induced alternating waveform at the output winding of the pulse transformer and for switching an output state according to said rectified waveform.
Claim 14
Dependent Claim
40 words
A ground isolation circuit for transferring pulses as claimed in claim 11 wherein said rectifying and state-switching means comprises diodes arranged to provide full wave rectification of said induced alternating signal, and a switching element responsive to said rectified signal.
Claim 15
Dependent Claim
50 words
A ground isolation circuit as claimed in claim 11 wherein said rectifying and state-switching means comprises a pair of parallel transistors arranged to conduct during alternate half cycles of said induced alternating waveform, the transistor outputs being superimposed to provide an output waveform to be supplied to said succeeding device.
Claim 16
Dependent Claim
20 words
A ground isolation circuit as claimed in claim 8 further comprising inverter means in advance of said coincidence gate means.
Claim 17
Dependent Claim
170 words
An isolating circuit for transferring signal pulses from a source device to a succeeding device with control of pulse waveform distortion, comprising: coincidence gate means comprising a pair of coincidence gates each receiving at one input the signal pulse waveform, oscillator means comprising means for supplying synchronous clock pulses of opposite polarity respectively to another input of each of said gates, a pulse transformer having its input windiNg connected between the outputs of said pair of coincidence gates, whereby said input winding receives superimposed alternating signals of opposite polarity for the duration of each of said signal pulses, said transformer having an isolated output winding across which a corresponding alternating waveform is induced, and switching means maintained in a preselected state by said induced alternating waveform, the output of said switching means being applied to said succeeding device, whereby said induced alternating waveform is substantially uniform in magnitude for the duration of each of said signal pulses to reliably control said switching means to provide a substantially distortionless output waveform.
Claim 18
Dependent Claim
170 words
An isolating circuit for transferring signal pulses from a source device to a succeeding device with control of pulse waveform distortion, comprising: coincidence gate means comprising a pair of coincidence gates each receiving at one input the signal pulse waveform, oscillator means comprising means for supplying synchronous clock pulses of opposite polarity respectively to another input of each of said gates, a pulse transformer having its input windiNg connected between the outputs of said pair of coincidence gates, whereby said input winding receives superimposed alternating signals of opposite polarity for the duration of each of said signal pulses, said transformer having an isolated output winding across which a corresponding alternating waveform is induced, and switching means maintained in a preselected state by said induced alternating waveform, the output of said switching means being applied to said succeeding device, whereby said induced alternating waveform is substantially uniform in magnitude for the duration of each of said signal pulses to reliably control said switching means to provide a substantially distortionless output waveform.
Claim 19
Dependent Claim
42 words
An isolating circuit for transferring pulses as claimed in claim 15 wherein said switching means comprises means for rectifying the induced alternating waveform at the output winding of the pulse transformer and for switching an output state according to said rectified waveform.
Claim 20
Dependent Claim
39 words
An isolating circuit for transferring pulses as claimed in claim 16 wherein said rectifying and state-switching means comprises diodes arranged to provide full wave rectification of said induced alternating signal, and a switching element responsive to said rectified signal.
Claim 21
Dependent Claim
49 words
An isolating circuit as claimed in claim 16 wherein said rectifying and state-switching means comprises a pair of parallel transistors arranged to conduct during alternate half cycles of said induced alternating waveform, the transistor outputs being superimposed to provide an output waveform to be supplied to said succeeding device.
Claim 22
Dependent Claim
19 words
An isolating circuit as claimed in claim 15 further comprising inverter means in advance of said coincidence gate means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |