公开(公告)号：US3566035A

公开(公告)日：1971-02-23

申请号：US3566035D

申请日：1969-07-17

Applicant: BELL TELEPHONE LABOR INC

Inventor： NOLL A MICHAEL ,  SCHROEDER MANFRED R

IPC: G10L25/90 ,  G10L1/04

CPC classification number: G10L25/90

Abstract: The periodicity or aperiodicity of a signal is determined, in a signal analyzer, from the so-called ''''cepstrum'''' of the signal; that is, from the Fourier transform of the logarithm of the power spectrum of the signal. The short-time cepstrum is obtained by passing the signal through a first spectrum analyzer followed by a logarithmic amplifier and a second spectrum analyzer. The cepstrum signal is characterized by a peak at a time proportional to the fundamental period during periodic portions of the signal, and by the absence of a peak during aperiodic portions of the signal.

公开(公告)号：US3493684A

公开(公告)日：1970-02-03

申请号：US3493684D

申请日：1966-06-15

Applicant: BELL TELEPHONE LABOR INC

Inventor： KELLY JAMES M ,  NOLL A MICHAEL ,  SCHROEDER MANFRED R

IPC: G10L19/02 ,  H04B1/66 ,  H04M1/00

CPC classification number: G10L19/02

公开(公告)号：US3183304A

公开(公告)日：1965-05-11

申请号：US17819062

申请日：1962-03-07

Applicant: BELL TELEPHONE LABOR INC

Inventor： SCHROEDER MANFRED R

IPC: H04M9/08 ,  H04R3/02

CPC classification number: H04M9/087 ,  H04R3/02

公开(公告)号：US3160711A

公开(公告)日：1964-12-08

申请号：US34560

申请日：1960-06-04

Applicant: BELL TELEPHONE LABOR INC

Inventor： SCHROEDER MANFRED R

IPC: H04B7/005 ,  H04J4/00

CPC classification number: H04J4/00 ,  H04B7/005

公开(公告)号：US3110771A

公开(公告)日：1963-11-12

申请号：US5927360

申请日：1960-09-29

Applicant: BELL TELEPHONE LABOR INC

Inventor： LOGAN JR BENJAMIN F ,  SCHROEDER MANFRED R

IPC: G10K15/10 ,  G10K15/12

CPC classification number: G10K15/10 ,  G10K15/12

公开(公告)号：US3566285A

公开(公告)日：1971-02-23

申请号：US3566285D

申请日：1968-07-26

Applicant: BELL TELEPHONE LABOR INC

Inventor： SCHROEDER MANFRED R

IPC: G10L11/00 ,  H04J3/16 ,  H03K5/08 ,  H03B3/02

CPC classification number: H04J3/1688 ,  G10L25/00

Abstract: BY REDUCING THE ENVELOPE OF A SIGNAL, SUCH AS A SPEECH SIGNAL, IN A NONLINEAR FASHION A MODIFIED SIGNAL IS PRODUCED WHICH, IN ADDITION TO BEING HIGHLY INTELLIGIBLE, EXHIBITS DESIRABLE PROPERTIES. PITCH SYNCHRONOUS GAPS, SMOOTHLY ESTABLISHED IN A REDUCED ENVELOPE SIGNAL IN PLACE OF INTERVALS OF LOW SIGNAL LEVELS, ARE EFFECTIVE IN ELIMINATING NOISE WHICH MASKS LOW LEVEL SIGNALS, REDUCING REVERBERATION, AND IN ADAPTING THE SIGNAL FOR MULTIPLEX TRANSMISSION. ENVELOPE REDUCTION IS EFFICIENTLY ACHIEVED BY CONTROLLABLY CENTER CLIPPING A SELECTED MOFULATION SIDEBAND OF A SIGNAL, FILTERING THE RESULTANT, AND RESTORING THE SIGNAL TO BASEBAND.

公开(公告)号：US3466547A

公开(公告)日：1969-09-09

申请号：US3466547D

申请日：1967-04-18

Applicant: BELL TELEPHONE LABOR INC

Inventor： FLANAGAN JAMES L ,  GOLDEN ROGER M ,  SCHROEDER MANFRED R

IPC: H04B7/015 ,  H04B1/10 ,  H04B1/62

CPC classification number: H04B7/015

公开(公告)号：US3405237A

公开(公告)日：1968-10-08

申请号：US46010165

申请日：1965-06-01

Applicant: BELL TELEPHONE LABOR INC

Inventor： DAVID JR EDWARD E ,  SCHROEDER MANFRED R ,  SONDHI MAN M

IPC: G10L25/90

CPC classification number: G10L25/90

公开(公告)号：US3346067A

公开(公告)日：1967-10-10

申请号：US53479066

申请日：1966-03-16

Applicant: BELL TELEPHONE LABOR INC

Inventor： SCHROEDER MANFRED R

IPC: G01N29/11

CPC classification number: G01N29/11

公开(公告)号：US3236949A

公开(公告)日：1966-02-22

申请号：US23853962

申请日：1962-11-19

Applicant: BELL TELEPHONE LABOR INC

Inventor： ATAL BISHNU S ,  SCHROEDER MANFRED R

IPC: H04R5/04 ,  H04S1/00

CPC classification number: H04R5/04 ,  H04S1/002