Signal sensing circuit

Claim 2

A signal sensing assembly for sensing audio signals and supplying power to a device in response thereto, said assembly comprising; input means (22) for supplying an audio signal, coupling means (C1) for eliminating dc components from the audio signal; input filter and amplifier means (32) for receiving said audio signal from said coupling means (C1) and amplifying said audio signal while attenuating frequency components above a first predetermined frequency producing a filtered signal, rectifier means (34) for receiving and rectifying said filtered signal to produce a level signal, comparator means (38) for receiving said level signal and comparing said level signal to a predetermined magnitude to produce a trigger signal, timer means (44) for receiving said trigger signal and producing a control signal for a predetermined time in response to said trigger signal, said timer means comprising a (44) retriggerable monostable (46) for producing said control signal for said predetermined time and for restarting said predetermined time in response to a subsequent reception of said trigger signal, and control means (48) for receiving said control signal to supply power to the device (14).

Claim 3

An assembly as set forth in claim 1 further characterized by including amplifier means (30) for amplifying said audio signal to produce said level signal.

Claim 4

A signal sensing assembly for sensing audio signals and supplying power to a device in response thereto, said assembly comprising: input means (22) for supplying an audio signal; first coupling means (C1) for eliminating dc components from the audio signal; input filter and amplifier means (30, 32) for receiving said audio signal from said first coupling means (C1) and for amplifying said audio signal while attenuating frequency components above a first predetermined frequency producing a filtered signal; rectifier means (34) for receiving and rectifying said audio signal and producing a rectified signal; low pass means (36) for receiving said rectified signal and producing a level signal upon receiving said rectified signal for a minimum duration; comparator means (38) for receiving said level signal and comparing said level signal to a predetermined magnitude to produce a trigger signal; timer means (44) for receiving said trigger signal and producing a control signal within a specified time from receiving said trigger signal and producing said control signal for a predetermined time in response to said trigger signal, said predetermined time being independent of said specified time and for resetting said predetermined time upon subsequent reception of said trigger signal; and control means (48) for receiving said control signal to supply power to the device (14).

Claim 5

A signal sensing assembly for sensing audio signals and supplying power to a device in response thereto, said assembly comprising: input means (22) for supplying an audio signal; first coupling means (C1) for eliminating dc components from the audio signal; input filter and amplifier means (30, 32) for receiving said audio signal from said first coupling means (C1) and for amplifying said audio signal while attenuating frequency components above a first predetermined frequency producing a filtered signal; rectifier means (34) for receiving and rectifying said audio signal and producing a rectified signal; low pass means (36) for receiving said rectified signal and producing a level signal upon receiving said rectified signal for a minimum duration; comparator means (38) for receiving said level signal and comparing said level signal to a predetermined magnitude to produce a trigger signal; timer means (44) for receiving said trigger signal and producing a control signal within a specified time from receiving said trigger signal and producing said control signal for a predetermined time in response to said trigger signal, said predetermined time being independent of said specified time and for resetting said predetermined time upon subsequent reception of said trigger signal; and control means (48) for receiving said control signal to supply power to the device (14).

Claim 6

An assembly as set forth in claim 3 further characterized by said timer means (44) including a retriggerable monostable (46) for producing said control signal for said predetermined time and for resetting said predetermined time in response to a subsequent reception of said trigger signal.

Claim 7

A signal sensing assembly for sensing audio signals and supplying power to a device in response thereto, said assembly comprising; input means (22) comprising first and second inputs for supplying an audio signal, summing means (24) for receiving said first (18) and second (20) inputs and summing said inputs (18, 20) to produce a combined audio signal (32); first coupling means (C1) for eliminating dc components from the combined audio signal; input filter and amplifier means (30, 32) for receiving said combined audio signal and filtering out frequency components above a first predetermined frequency to produce a filtered audio signal, second coupling means (C2) for eliminating dc components from the filtered audio signal; rectifier means (34) for receiving and half wave rectifying said amplified signal to produce a rectified signal, low pass means (36) for receiving said rectified signal from said rectifier means (34) and for producing a level signal upon receiving said rectified signal for a minimum duration; comparator means (38) for receiving said level signal and comprising said level signal to a predetermined magnitude to produce a trigger signal, timer means (44) for receiving said trigger signal and producing in response to said trigger signal and for an initial period a control signal having a predetermined duration and for restarting said predetermined duration upon subsequent reception of said trigger signal during said initial period, said timer means (44) including a retriggerable monostable (46) for producing said control signal for said predetermined duration and for restarting said predetermined duration in response to a subsequent reception of said trigger signal; and control means (48) for receiving said control signal to cause a power supply means to supply power for powering the device (14).

Claim 8

A signal sensing assembly for sensing audio signals and supplying power to a device in response thereto, said assembly comprising; input means (22) comprising first and second inputs for supplying an audio signal, summing means (24) for receiving said first (18) and second (20) inputs and summing said inputs (18, 20) to produce a combined audio signal (32); first coupling means (C1) for eliminating dc components from the combined audio signal; input filter and amplifier means (30, 32) for receiving said combined audio signal and filtering out frequency components above a first predetermined frequency to produce a filtered audio signal, second coupling means (C2) for eliminating dc components from the filtered audio signal; rectifier means (34) for receiving and half wave rectifying said amplified signal to produce a rectified signal, low pass means (36) for receiving said rectified signal from said rectifier means (34) and for producing a level signal upon receiving said rectified signal for a minimum duration; comparator means (38) for receiving said level signal and comprising said level signal to a predetermined magnitude to produce a trigger signal, timer means (44) for receiving said trigger signal and producing in response to said trigger signal and for an initial period a control signal having a predetermined duration and for restarting said predetermined duration upon subsequent reception of said trigger signal during said initial period, said timer means (44) including a retriggerable monostable (46) for producing said control signal for said predetermined duration and for restarting said predetermined duration in response to a subsequent reception of said trigger signal; and control means (48) for receiving said control signal to cause a power supply means to supply power for powering the device (14).

Claim 9

An assembly as set forth in claim 5 further characterized by said input comprising a first single ended input (-8) from a first channel and a second single ended input (20) from a second channel.

Claim 10

An assembly as set forth in claim 6 further characterized by including audio transducer means (16) for receiving an audio signal and producing audible signals.

Claim 11

An assembly as set forth in claim 6 further including in combination said device, said device comprising first channel amplifier means (14) for receiving and amplifying said audio signal on said first single ended input (18) in response to power supplied from said control means.

Claim 12

An assembly as set forth in claim 8 further characterized by said control means (48) including switch means for receiving said control signal and connecting said power supply means to the device during said predetermined time and disconnecting said power supply means in the absence of said control signal.

Claim 13

An assembly as set forth in claim 9 further characterized by said summing means (24) comprising resistive means on each of said inputs and connected at a common point producing said audio signal.

Claim 14

An assembly as set forth in claim 10 further characterized by said first coupling means comprising a capacitor for coupling ac components.

Claim 15

An assembly as set forth in claim 11 further characterized by said input filter and amplifier means (32) comprising an operational amplifier having feedback comprising a resistor and a capacitor in parallel to slew rate limit said amplifier.

Claim 16

An assembly as set forth in claim 12 further characterized by said second coupling means (C2) comprising a capacitor.

Claim 17

An assembly as set forth in claim 13 further characterized by said rectifier means (34) comprising a diode.

Claim 18

An assembly as set forth in claim 14 further characterized by said low pass means (36) comprising a resistor (R12) and capacitor (C6).

Claim 19

An assembly as set forth in claim 15 further characterized by said comparator means (38) comprising an operational amplifier having a first input connected to said low pass filter means (36) and a second input connected a resistive divider for establishing the predetermined magnitude.

Claim 20

An assembly as set forth in claim 6 further characterized by said power supply means comprising a battery.

Claim 23

A method as set forth in claim 18 further including producing a control signal within a specified time of receiving the level signal, the specified time being independent of the predetermined time.