Decreasing time duration of recorded speech
AssigneeInternational Business Machines Corporation
InventorsCharles R. Bringol, Gary F. Snyder
Life of this patent
Estimating the term…
Abstract
Disclosed is apparatus for and a method of decreasing the time duration of playback of recorded speech without distortion. Speech recorded at a normal rate is played back at a higher rate using two variable length buffers in alternating fashion to receive sampled speech segments. Threshold analysis logic circuitry is provided to continually compare the output voltage levels of both buffers and to switch the output between the buffers to a using device when the voltage level of both buffers is approximately zero and of an equal amplitude. In this way output to the using device consists of segments from both buffers joined with a minimum of generated noise and no associated dead zone without regard to any predetermined segment length.
Claims9
In a system for time compression of prerecorded speech signals which are played back at a rate greater than that at which they were recorded and in which the input speech is loaded alternately into first and second buffers and output from the buffers is alternatively applied to a using device, said system including
- means for loading one of said buffers while the other is providing an output to said using device, the improvement comprising:
- means for changing the source of output applied to said using device from said first buffer to said second buffer when the output level of both of said buffers falls within a predetermined range.
Apparatus for time compressing speech signals which includes an input terminal for receiving the speech signals, an analog to digital converter connected to the input terminal, first and second dynamic storage means connected to the analog to digital converter, means for reading the signals into either the first or second storage means at a first rate, means for reading out from either the first or second storage means at a second rate, first and second digital to analog converters connected to the outputs of the first and second storage means, means for comparing the outputs of the first and second digital to analog converters, the improvement comprising:
- means responsive to said means for comparing for alternating reading in and reading out when the output of said digital to analog converters is within a certain predetermined range, whereby segments of speech signals from said first and second dynamic storage means are joined with a minimum of generated noise.
A method of joining time compressed recorded speech signals in a substantially noise free manner comprising the steps of:
- sampling speech signals;
- storing said sampled signals at a first rate in one of a pair of storage elements;
- reading out said sampled speech signals at a second rate from the other of the pair of storage elements;
- continually comparing output voltages from each storage element;
- switching input and output clocks applied to the storage elements when the voltage levels from each storage device are substantially equal and within a predetermined range of a zero crossing;
- and switching from one to the other of the storage elements as the source of output applied to a using device.
Dependencies are inferred from the claim text.