EP0213846A2
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EP
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Waveform generation method
Assignee: Advanced Micro Devices Inc
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Filing: 1986-08-14
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Granted: —
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Expires: 2006-08-14
Abstract
Abstract A method for the generation of precise single- and dual-tone multiple-frequency signals using only digital signal processing techniques is disclosed. The frequency, amplitude and cadence of the tone(s) generated are programmable via a microprocessor. The tones generated are suitable for the dual-tone multiple-frequency (DTMF) used in communication networks as well as for tone message and tone ringer functions. The principle of operation is that a triangular wave is produced (820, 826) by the repetitive addition of a user-supplied "delta" value to an accumulator until an overflow condition occurs, and then the delta value is repetitively subtracted from the accumulator until an underflow condition occurs. Next, a trapezoidal wave is produced by multiplying (822, 828) the triangular waveform by 1.5 and truncating the resulting waveform at selectable positive and negative levels. The desired amplitude is then established by multiplication by a selectable attenuation (824, 830) value. A DTMF waveform is obtained by generating two waveforms as just described and then summing (832) the resulting waveforms, producing a waveform of a frequency with less than 1% deviation. An exemplary embodiment illustrates the waveform generation method of the present invention in the audio processor section of a digital subscriber controller.
Inventors
- 👤 Arthur Lange
- 👤 P. Venkitakrishnan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 22:30
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/45; H04Q1/457; H04Q1/4575
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
124 words
A method of generating a waveform having a nominal frequency F and an amplitude A, comprising the steps: a) repetitively adding a predetermined value, D, to itself at predetermined intervals, S, until said sum exceeds said value A; b) repetitively subtracting said predetermined value D from said value formed during step (a) at said predetermined intervals, S, until said difference is less than -A; c) returning to step (a); d) multiplying said waveform generated in steps (a), (b) and (c) by a predetermined value, M; e) truncating said waveform generated in step (d) at A whenever it exceeds said value A and at -A whenever it is less than -A; and f) multiplying said waveform generated in step (e) by a predetermined value, V.
Claim 2
Independent Claim
124 words
A method of generating a waveform having a nominal frequency F and an amplitude A, comprising the steps: a) repetitively adding a predetermined value, D, to itself at predetermined intervals, S, until said sum exceeds said value A; b) repetitively subtracting said predetermined value D from said value formed during step (a) at said predetermined intervals, S, until said difference is less than -A; c) returning to step (a); d) multiplying said waveform generated in steps (a), (b) and (c) by a predetermined value, M; e) truncating said waveform generated in step (d) at A whenever it exceeds said value A and at -A whenever it is less than -A; and f) multiplying said waveform generated in step (e) by a predetermined value, V.
Claim 3
Dependent Claim
83 words
A waveform generation method according to claim 1 employing a predetermined base frequency B, and wherein step (a) further calls for determining said values D and S from said frequency F by performing the steps: (a1) dividing B by F; (a2) rounding said quotient determined in step (a1) to the nearest even whole number said rounded quotient being S; (a3) dividing 2*A by S/2; and (a4) increasing said quotient determined in step (a3) to the next whole number, said increased quotient being D.
Claim 4
Dependent Claim
26 words
A waveform generation method according to claim 1 wherein said frequency F is chosen from a range between 300 cycles per second (Hz) and 2666 Hz.
Claim 5
Dependent Claim
15 words
A waveform generation method according to claim 1 wherein said predetermined value M is 1.5.
Claim 6
Independent Claim
252 words
A method of generating a dual-tone multi-frequency waveform having a first frequency F₁ and a first amplitude A₁ and a second frequency F₂ and a second amplitude A₂, comprising the steps: a) repetitively adding a predetermined value, D₁, to itself at predetermined intervals, S₁, until said sum exceeds said value A₁; b) repetitively subtracting said predetermined value D from said value formed during step (a) at said predetermined intervals, S₁, until said difference is less than -A₁; c) returning to step (a); d) multiplying said waveform generated in steps (a), (b) and (c) by a predetermined value, M₁; e) truncating said waveform generated in step (d) at A₁ whenever it exceeds said value A₁ and at -A₁ whenever it is less than -A₁; f) multiplying said waveform generated in step (e) by a predetermined value, V₁; g) repetitively adding a predetermined value, D₂, to itself at predetermined intervals, S₂, until said sum exceeds said value A₂; h) repetitively subtracting said predetermined value D₂ from said value formed during step (g) at said predetermined intervals, S₂, until said difference is less than -A₂; i) returning to step (g); j) multiplying said waveform generated in steps (g), (h) and (i) by a predetermined value, M₂; k) truncating said waveform generated in step (j) at A₂ whenever it exceeds said value A₂ and at -A₂ whenever it is less than -A₂; l) multiplying said waveform generated in step (k) by a predetermined value, V₂; and m) summing said waveforms generated at steps (f) and (l).
Claim 7
Independent Claim
252 words
A method of generating a dual-tone multi-frequency waveform having a first frequency F₁ and a first amplitude A₁ and a second frequency F₂ and a second amplitude A₂, comprising the steps: a) repetitively adding a predetermined value, D₁, to itself at predetermined intervals, S₁, until said sum exceeds said value A₁; b) repetitively subtracting said predetermined value D from said value formed during step (a) at said predetermined intervals, S₁, until said difference is less than -A₁; c) returning to step (a); d) multiplying said waveform generated in steps (a), (b) and (c) by a predetermined value, M₁; e) truncating said waveform generated in step (d) at A₁ whenever it exceeds said value A₁ and at -A₁ whenever it is less than -A₁; f) multiplying said waveform generated in step (e) by a predetermined value, V₁; g) repetitively adding a predetermined value, D₂, to itself at predetermined intervals, S₂, until said sum exceeds said value A₂; h) repetitively subtracting said predetermined value D₂ from said value formed during step (g) at said predetermined intervals, S₂, until said difference is less than -A₂; i) returning to step (g); j) multiplying said waveform generated in steps (g), (h) and (i) by a predetermined value, M₂; k) truncating said waveform generated in step (j) at A₂ whenever it exceeds said value A₂ and at -A₂ whenever it is less than -A₂; l) multiplying said waveform generated in step (k) by a predetermined value, V₂; and m) summing said waveforms generated at steps (f) and (l).
Claim 8
Dependent Claim
83 words
A waveform generation method according to claim 5 employing a predetermined base frequency B, and wherein step (a) further calls for determining said values D₁ and S₁ from said frequency F₁ by performing the steps: (a1) dividing B by F₁; (a2) rounding said quotient determined in step (a1) to the nearest even whole number said rounded quotient being S₁; (a3) dividing 2*A₁ by S₁/2; and (a4) increasing said quotient determined in step (a3) to the next whole number, said increased quotient being D₁.
Claim 9
Dependent Claim
83 words
A waveform generation method according to claim 5 employing a predetermined base frequency B, and wherein step (a) further calls for determining said values D₂ and S₂ from said frequency F₂ by performing the steps: (a1) dividing B by F₂; (a2) rounding said quotient determined in step (a1) to the nearest even whole number said rounded quotient being S₂; (a3) dividing 2*A₂ by S₂/2; and (a4) increasing said quotient determined in step (a3) to the next whole number, said increased quotient being D₂.
Claim 10
Dependent Claim
26 words
A waveform generation method according to claim 5 wherein said frequency F₁ is chosen from a range between 697 cycles per second (Hz) and 1633 Hz.
Claim 11
Dependent Claim
26 words
A waveform generation method according to claim 5 wherein said frequency F₂ is chosen from a range between 697 cycles per second (Hz) and 1633 Hz.
Claim 12
Dependent Claim
31 words
A waveform generation method according to claim 5 further including a method for generating tone message and tone ringer waveforms wherein one of said predetermined values V₁ and V₂ is zero.
Claim 13
Dependent Claim
17 words
A waveform generation method according to claim 5 wherein said predetermined values M₁ and M₂ are 1.5.
References Cited (Backward Citations)
No citation records indexed.
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