Driver circuit for tone generator

Claim 2

A driver circuit for a noise generator that is adapted to cause said noise generator to produce a chime type of audio output comprising: first oscillator means for producing a relatively high frequency signal having a decaying amplitude characteristic; second oscillator means for producing a relatively low frequency signal having a decaying amplitude characteristic; summing means for combining said high and low frequency signals; modulating means connected to said summing means for producing a pulse width modulated substantially square wave signal from said combined signal at a frequency related to the frequency of said high frequency signal and having a duty cycle that varies in accordance with the amplitude of said low frequency signal; and driver means connected to said noise generator for driving said noise generator in accordance with said modulated signal.

Claim 3

The driver circuit of claim 1 wherein said second oscillator means is adapted to produce a signal having a substantially sawtooth type waveform.

Claim 4

The driver circuit of claim 2 wherein said first oscillator means is adapted to produce a signal having a substantially sawtooth type waveform.

Claim 5

The driver circuit of claim 3 wherein said first and second oscillator means are adapted to produce substantially square wave signals at their conventional outputs and said substantially sawtooth type waveform signals at their conventional inputs, and further wherein said summing means is connected to the conventional inputs of said first and second oscillator means.

Claim 6

The driver circuit of claim 3 wherein said modulating means comprises a logic gate.

Claim 7

The driver circuit of claim 5 wherein said logic gate comprises an inverter.

Claim 8

The driver circuit of claim 1 wherein said driver means comprises a solid state switching element that is connected in series with said noise generator and is adapted to cycle from a conductive state to a nonconductive state in accordance with the duty cycle of said modulated signal.

Claim 9

A driver circuit for a noise generator that is adapted to cause said noise generator to produce a chime type audio output comprising: first oscillator means for producing a relatively high frequency signal having a substantially sawtooth type waveform; second oscillator means for producing a relatively low frequency signal having a substantially sawtooth type waveform; summing means connected to said first and second oscillator means for combining said high and low frequency signals; logic gate means connected to said summing means for producing a pulse width modulated substantially square wave signal from said combined signal at the frequency of said high frequency signal and having a duty cycle that varies in accordance with the amplitude of said low frequency signal; and driver circuit means connected in circuit with said noise generator for driving said noise generator in accordance with the varying duty cycle of said modulated signal.

Claim 10

A driver circuit for a noise generator that is adapted to cause said noise generator to produce a chime type audio output comprising: first oscillator means for producing a relatively high frequency signal having a substantially sawtooth type waveform; second oscillator means for producing a relatively low frequency signal having a substantially sawtooth type waveform; summing means connected to said first and second oscillator means for combining said high and low frequency signals; logic gate means connected to said summing means for producing a pulse width modulated substantially square wave signal from said combined signal at the frequency of said high frequency signal and having a duty cycle that varies in accordance with the amplitude of said low frequency signal; and driver circuit means connected in circuit with said noise generator for driving said noise generator in accordance with the varying duty cycle of said modulated signal.

Claim 11

The driver circuit of claim 1 wherein the frequency of said pulse width modulated signal is equal to the frequency of said high frequency signal.

Claim 12

A driver circuit for a tone generator that is adapted to cause said tone generator to produce a chime type audio output, including: first circuit means for producing a relatively high frequency signal having a decaying amplitude characteristic; second circuit means for causing said relatively high frequency signal to vary according to a relatively low frequency pattern having a decaying amplitude characteristic; and third circuit means for producing a pulse width modulated substantially square wave drive signal at a frequency related to said relatively high frequency signal and having a duty cycle that varies in accordance with the amplitude characteristic of said relatively low frequency pattern.

Claim 13

A driver circuit for a tone generator that is adapted to cause said tone generator to produce a chime type audio output, including: first circuit means for producing a relatively high frequency signal having a decaying amplitude characteristic; second circuit means for causing said relatively high frequency signal to vary according to a relatively low frequency pattern having a decaying amplitude characteristic; and third circuit means for producing a pulse width modulated substantially square wave drive signal at a frequency related to said relatively high frequency signal and having a duty cycle that varies in accordance with the amplitude characteristic of said relatively low frequency pattern.

Claim 14

The driver circuit of claim 10 wherein said pulse width modulated signal comprises a digital square wave signal having either a logic HI amplitude level or a logic LO amplitude level.

Claim 15

The driver circuit of claim 11 wherein said second circuit means includes an oscillator circuit for producing a signal at said relatively low frequency.

Claim 16

The driver circuit of claim 12 wherein said relatively low frequency signal produced by said oscillator circuit has a decaying amplitude characteristic.

Claim 17

The driver circuit of claim 13 wherein said second circuit means further includes means for combining said relatively low frequency signal and said relatively high frequency signal such that said relatively high frequency signal is effectively superimposed onto said relatively low frequency signal.

Claim 18

The driver circuit of claim 10 wherein said third circuit means includes a transistor having its collector and emitter terminals connected between said tone generator and ground potential.

Claim 19

The driver circuit of claim 15 wherein said third circuit means further includes logic gating means connected to the output of said second circuit means.

Claim 20

The driver circuit of claim 16 wherein the output of said logic gating means is connected to the base of said transistor.