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Pulse Excited Two Way Channel Vocoder

IP.com Disclosure Number: IPCOM000092685D
Original Publication Date: 1967-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Rothauser, EH: AUTHOR [+2]

Abstract

The drawing shows the system during speech transmission from A to 13. In this operational mode the filter set located in A is used for speech analysis. The output of each filter is connected to a device which yields an output related to the energy level of the input speech signal within the pass band of the filter. Normally the device comprises a rectifier and a low pass.

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Pulse Excited Two Way Channel Vocoder

The drawing shows the system during speech transmission from A to 13. In this operational mode the filter set located in A is used for speech analysis. The output of each filter is connected to a device which yields an output related to the energy level of the input speech signal within the pass band of the filter. Normally the device comprises a rectifier and a low pass.

In each spectrum channel the output of this device is used to modulate the excitation pulses provided by the excitation channel located in A. In the drawing the modulators are represented as switches. The modulated excitation pulses are transmitted and are used immediately to excite the band pass filters of the set located in B by the pulse excitation principle.

The direction of transmission is automatically changed when the input speech signal in A assumes the zero level for a period exceeding the specified one and the input speech signal in B assumes a level other than zero. By this signal in A, a break indicator excites a relay and the filters are connected to the incoming excitation pulses and are thus used for synthesis of the speech output signal in
A.

As long as there are incoming excitation pulses in any of the spectrum channels, the direction of transmission cannot be changed as the level on the input of the break indicator is switched to zero by a relay. The switch is reset after a certain time passes without excitation pulses entering. The system...