Tone generation method and apparatus using stored reference calibration coefficients
AssigneeBell Telephone Laboratories, Incorporated
InventorPaul A. Mercer
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Abstract
A tone generator operates in a multiplicative (19) manner with respect to a reference signal (20) for providing a selectable sequence of tones. A digital calibration coefficient is constructed for at least one tone for modifying (22) the reference signal to a value that produces a predetermined output amplitude for the tone. The coefficient is stored (16) for subsequent recall each time the predetermined output amplitude for the tone is required.
Claims18
A tone signal generator including a source (16) of selectable sets of digital coefficient signals defining a predetermined analog signal waveform, and means (19) for multiplying said coefficient signals by a reference signal for producing an analog tone signal which is recurrent at a predetermined rate, the generator comprising
- means (53, 13) for feeding back the output of said generator to control the magnitude of said reference signal for establishing a predetermined generator output tone amplitude.
An analog signal tone generator including a source (12) of at least one set of digital coefficient signals defining an analog waveform of predetermined configuration, and means (19), having an analog reference signal input and responsive to said coefficient signals, for producing said analog signal tone, the generator comprising
- means (53), responsive to said analog signal tone, for generating a digital error signal indicating a difference in magnitude between said tone and a predetermined reference, and
- means (13, 22), responsive to said digital error signal, for modifying said analog reference signal to reduce the magnitude of said difference.
A method for generating at least one tone having a predetermined output amplitude, the method using a multiplication process with respect to a reference signal and comprising the steps of
- operating the process to produce tone output of uncalibrated amplitude,
- constructing in response to said tone output a calibrating signal having a value which, when applied to modify said reference signal, causes said uncalibrated amplitude tone output to assume said predetermined output amplitude for such tone, and
- modifying said reference signal in response to said calibrating signal.
Dependencies are inferred from the claim text.