公开(公告)号：CA1120619A

公开(公告)日：1982-03-23

申请号：CA335493

申请日：1979-09-12

Applicant: IBM

Inventor： SCHINDLER HANS R ,  VETTIGER PETER

IPC: G10L11/00 ,  H04B1/66 ,  H04J6/02

Abstract: METHOD AND APPARATUS FOR THE TRANSMISSION OF SPEECH SIGNALS of the Invention For the multiplex transmission of coded speech signals in periodic frames, single segments (blocks of coded samples) are selectively suppressed for redundancy reduction, and are replaced on the receiver side by optimally correlated subsections of equal length from previously transmitted segments. On the transmitter side, a multiplicity of compare operations are made for each speech signal, between the respective newest coded segment and a step wise shifted subsection window of previous segments, to determine the best correlated subsection, i.e. the one which is most suitable as replacement and the respective relative offset and correlation. From a group of speech signals, the one signal, or several signals, having the best correlation is selected for suppression of a segment before transmission. Instead of each missing segment an indication of the corresponding optimum offset is transmitted in the frame header. In the receiver for each speech signal a few previous segments are kept in storage from which then, with the aid of the received offset indication the optimally suited subsection can be selected and used as replacement. SZ9-78-002

公开(公告)号：CA996276A

公开(公告)日：1976-08-31

申请号：CA143608

申请日：1972-06-01

Applicant: IBM

Inventor： FREI ARMIN H ,  SCHINDLER HANS R ,  VETTIGER PETER

IPC: H04N7/32 ,  H04N19/124 ,  H04N19/50

Abstract: Method and device for coding and decoding video signals employing two different modes: Delta Coding for regions of minor amplitude changes, and DPCM Coding for edges which exhibit large amplitude changes. Switching between modes is effected by the bit stream carrying the video information, with a minimum of extra marker bits. Further improvement is achieved by using a higher scanning frequency for delta coding and transferring a reduced number of bits extracted by majority selection.

公开(公告)号：FR2356325A1

公开(公告)日：1978-01-20

申请号：FR7716040

申请日：1977-05-17

Applicant: IBM

Inventor： SCHINDLER HANS R ,  VETTIGER PETER

IPC: H04M3/02 ,  H04M3/22 ,  H04M19/02 ,  H04M3/00

Abstract: In an extension line circuit, an off-hook condition is detected during ringing by superimposing in each ringing cycle the values of the line current existing at two sampling instants exactly one-half cycle apart, and testing whether the sum (or mean value) exceeds a given threshold. When DC current starts flowing due to the set going off-hook, the mean value of the two values will pass a threshold.

公开(公告)号：FR2343378A1

公开(公告)日：1977-09-30

申请号：FR7702068

申请日：1977-01-18

Applicant: IBM

Inventor： SCHINDLER HANS R ,  VETTIGER PETER

IPC: H04B3/03 ,  H04B1/58 ,  H04M19/00 ,  H04M1/76

Abstract: This invention comprises a telephone hybrid circuit having two opto-coupler arrangements for transferring voice signals from the two-wire line to a port of the switching system on one hand and from a port of the switching system to the two-wire line on the other hand. In addition, a pair of feeder circuits in the form of current sources comprising active elements are provided for feeding a constant positive direct current to one wire of the two-wire line and a negative direct current of equal magnitude to the other wire of the two-wire line. Each of the current sources includes control circuitry for maintaining a constant ratio between the current furnished by the current source and a control current common to both current sources. A control current path is connected to the output of one of the opto-coupler arrangements for generating a common control current in response to a dc signal and a superimposed voice signal received from a port of the switching system. The other opto-coupler arrangement couples the signals from the two-wire line to a port of the switching system.

公开(公告)号：CA1073569A

公开(公告)日：1980-03-11

申请号：CA281417

申请日：1977-06-27

Applicant: IBM

Inventor： SCHINDLER HANS R ,  VETTIGER PETER

IPC: H04M3/02 ,  H04M3/22 ,  H04M19/02 ,  H04M1/72

Abstract: A METHOD AND APPARATUS FOR MONITORING THE ON/OFF-HOOK STATUS OF A TELEPHONE SET In an extension line circuit, an off-hook condition is detected during ringing by superimposing in each ringing cycle the values of the line current existing at two sampling instants exactly one-half cycle apart, and testing whether the sum (or mean value) exceeds a given threshold. When DC current starts flowing due to the set going offhook, the mean value of the two values will pass a threshold. Sample pulses can be derived in common for all line circuits from positive-going zero crossings of the ringing supply signal. The circuit acts as a notch filter centered exactly at the actual frequency of the ringing signal.

公开(公告)号：CA960316A

公开(公告)日：1974-12-31

申请号：CA142670

申请日：1972-05-19

Applicant: IBM

Inventor： SCHINDLER HANS R ,  VETTIGER PETER

IPC: H03K3/64