# US 10,083,000 B2 · Mitigating an induced electrical signal from an appliance in a powered-off state

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,083,000 B2
- Document ID: US10083000B2
- Status: Granted
- Kind: B2
- Application number: 15/482,143
- Filed: 2017-04-07
- Published: 2017-11-09
- Granted: 2018-09-25
- Earliest claimed: 2016-05-06
- Assignees: Cis Secure Computing, Inc.
- Applicants: CIS Secure Computing, Inc.
- Inventors: Daniel Gavin; Frederick E. Koenig
- Web page: https://patentgrep.com/patent/US10083000B2

## CPC

- G06F 3/165: {Management of the audio stream, e.g. setting of volume, audio stream path}
- G06F 21/602: {Providing cryptographic facilities or services}
- G06F 21/85: interconnection devices, e.g. bus-connected or in-line devices
- H04M 3/205: {Eavesdropping prevention - indication of insecurity of line or network}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)

## Abstract

An isolation unit may include input pins to receive an electrical signal induced by ambient sound waves incident on an appliance in a powered-off state, one or more first transformers, connected to the input pins, to electrically isolate the induced electrical, one or more second transformers, connected to the first transformers, to provide a common mode choke function on the induced electrical signal, one or more inductors, connected to the one or more second transformers, one or more resistors, connected to the one or more inductors, wherein the one or more inductors and the one or more resistors are configured to limit an amplitude of a current of the induced electrical signal, and output pins, connected to the one or more inductors, to receive a modified electrical signal from the one or more inductors to propagate the modified electrical signal to a downstream cable.

## Claims

### Claim 1

An isolation unit, comprising:
a signal modifier, configured to:
receive, at a plurality of first transformers, an induced electrical signal from an appliance, wherein the induced electrical signal is induced by ambient sound waves incident on the appliance;
modify, by the plurality of first transformers, the induced electrical signal by filtering one or more frequencies of the induced electrical signal to produce a modified electrical signal that may not be transformed into an intelligible audio signal; and
output the modified electrical signal.

### Claim 2 (depends on 1)

The isolation unit of claim 1, wherein the induced electrical signal is one of:
triboelectrically induced by the ambient sound waves incident on the appliance; and
piezoelectrically induced by the ambient sound waves incident on the appliance.

### Claim 3 (depends on 1)

The isolation unit of claim 1, wherein the induced electrical signal is induced by the ambient sound waves incident on the appliance when the appliance is in a powered-off state.

### Claim 4 (depends on 1)

The isolation unit of claim 1, wherein the plurality of first transformers are configured to electrically isolate the induced electrical signal.

### Claim 5 (depends on 4)

The isolation unit of claim 4, wherein the signal modifier further comprises:
one or more second transformers configured to:
receive the induced electrical signal from the plurality of first transformers; and
provide a common mode choke function on the induced electrical signal.

### Claim 6 (depends on 5)

The isolation unit of claim 5, wherein the one or more second transformers are configured to cancel one or more aspects of an amplitude of the induced electrical signal.

### Claim 7 (depends on 5)

The isolation unit of claim 5, wherein the signal modifier further comprises:
one or more inductors configured to limit an amplitude of a current of the induced electrical signal.

### Claim 8 (depends on 7)

The isolation unit of claim 7, wherein the signal modifier further comprises:
one or more resistors in communication with the one or more inductors,
wherein the one or more inductors and the one or more resistors are configured to limit the amplitude of the current of the induced electrical signal.

### Claim 9 (depends on 1)

The isolation unit of claim 1, wherein the plurality of first transformers are configured to attenuate the one or more frequencies of the induced electrical signal in range of from approximately 200 Hz to approximately 10,000 Hz.

### Claim 10 (depends on 1)

The isolation unit of claim 1, wherein the plurality of first transformers are configured to attenuate the one or more frequencies of the induced electrical signal in a range of from approximately 300 Hz to approximately 5,000Hz.

### Claim 11 (depends on 1)

The isolation unit of claim 1, wherein the signal modifier is further configured such that an amplitude of the modified electrical signal is substantially below −120dB.

### Claim 12

A method of modifying an induced electrical signal that is induced by ambient sound waves incident on an appliance, comprising:
receiving, at a plurality of first transformers of an isolation unit, the induced electrical signal from the appliance;
modifying, by the plurality of first transformers, the induced electrical signal by filtering one or more frequencies of the induced electrical signal to produce a modified electrical signal that may not be transformed into an intelligible audio signal; and
outputting the modified electrical signal.

### Claim 13 (depends on 12)

The method of claim 12, wherein the induced electrical signal is one of:
triboelectrically induced by the ambient sound waves incident on the appliance; and
piezoelectrically induced by the ambient sound waves incident on the appliance.

### Claim 14 (depends on 12)

The method of claim 12, wherein the induced electrical signal is induced by the ambient sound waves incident on the appliance when the appliance is in a powered-off state.

### Claim 15 (depends on 12)

The method of claim 12, wherein modifying, by the plurality of first transformers, the induced electrical signal by filtering one or more frequencies of the induced electrical signal to produce a modified electrical signal that may not be transformed into an intelligible audio signal comprises:
electrically isolating the induced electrical signal by one or more first transformers.

### Claim 16 (depends on 15)

The method of claim 15, wherein modifying, by the plurality of first transformers, the induced electrical signal by filtering one or more frequencies of the induced electrical signal to produce a modified electrical signal that may not be transformed into an intelligible audio signal comprises:
receiving, at one or more second transformers, the induced electrical signal from the plurality of first transformers, and providing a common mode choke function on the induced electrical signal.

### Claim 17 (depends on 16)

The method of claim 16, further comprising:
canceling, by the one or more second transformers, one or more aspects of an amplitude of the induced electrical signal.

### Claim 18 (depends on 12)

The method of claim 12, wherein filtering the one or more frequencies of the induced electrical signal comprises attenuating one or more frequencies of the induced electrical signal in range of from approximately 200 Hz to approximately 10,000 Hz.

### Claim 19 (depends on 12)

The method of claim 12, wherein filtering the one or more frequencies of the induced electrical signal comprises attenuating one or more frequencies of the induced electrical signal in range of from approximately 300 Hz to approximately 5,000 Hz.

### Claim 20 (depends on 12)

The method of claim 12, wherein an amplitude of the modified electrical signal is substantially below −120 dB.

### Claim 21 (depends on 12)

The method of claim 12, wherein modifying the induced electrical signal to produce a modified electrical signal that may not be transformed into an intelligible audio signal comprises:
limiting, by one or more inductors, an amplitude of a current of the induced electrical signal.

### Claim 22 (depends on 21)

The method of claim 21, wherein limiting, by the one or more inductors, the amplitude of the current of the induced electrical signal comprises:
limiting, by the one or more inductors and one or more resistors in communication with the one or more inductors, the amplitude of the current of the induced electrical signal.