Patent
Hybrid companding delta modulation system
TLDR
In this article, a hybrid companding delta modulation system is proposed for coding a speech signal, which employs both syllabic and instantaneous companding schemes, and the system can be made as large as the range of the input signal level.Abstract:
A hybrid companding delta modulation system is an improvement of adaptive delta modulation and is particularly suitable for coding a speech signal. It employs both syllabic and instantaneous companding schemes. The syllabic compandor provides a long term step size of the quantizer which varies relatively slowly by estimating either the envelope of slope or amplitude variation of the input signal. On the other hand, the instantaneous compandor adjusts the step size instantaneously according to a predetermined control logic in response to variations of the input signal. With the hybrid companding delta modulation system the dynamic range of the system can be made as large as the range of the input signal level. The signal-to-quantization noise ratio is improved over presently known adaptive delta modulation systems. Finally, the effect of channel errors is minimized.read more
Citations
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References
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Patent
Feedback residue compression for digital speech systems
TL;DR: In this paper, a digital speech compression system using a predictive feedback loop is described, which consists of a first adder into which the digital signal is fed followed by a quantizer and a compression logic.
Patent
Digital encoder/decoder
TL;DR: An average peak slope companded delta codec for converting an analog signal to a corresponding digital signal and vice versa includes a comparator which receives an analog and a variable reconstruction signal and converts the analog signal into a digital data bit stream as discussed by the authors.
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Adaptive delta-modulation system
TL;DR: In this paper, a delta-modulated output signal is fed through a shift register, to the individual stages of which the inputs of a coincidence gate are connected, and the output signal of the coincidence gate is transmitted through a narrowband filter tuned to a frequency f equal to the symbol transmission rate of the data-waveform modulated input signal v, which is utilized to control quantization step size.
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Adaptive code modulation improvement in digital code modulators
TL;DR: In this article, the average rate of change in the input signal over an immediately preceding short time interval is derived from the signal generated locally in the decoder, and this quantity is fed back to adapt the magnitude of a reference input.
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Digital companded delta modulator
TL;DR: In this article, a digital companded delta modulator comprising a comparator having a first input connected to receive an input analog signal, a second input obtained from an integrator located in the conventional feedback loop of the delta modulators, and a binary up and down counter is connected to the pulse generating means through a control circuit which makes the decision as to whether an up count a down count or no count at all is required.