公开(公告)号：GB1093102A

公开(公告)日：1967-11-29

申请号：GB1316665

申请日：1965-03-29

Applicant: IBM

Inventor： BANDAT KURT ,  LAMPARTER HELMUT ,  PAULUS ERWIN ,  ROTHAUSER ERNST ,  SPRUTH WILHELM

IPC: G10L25/90

Abstract: 1,093,102. Vocoder excitation function generator; pulse modulation systems. INTERNATIONAL BUSINESS MACHINES CORPORATION. March 29, 1965 [April 6, 1964], No. 13166/65. Headings H4L and H4R. In a vocoder the excitation function, which is a series of pulses corresponding to unidirectional zero crossings of the fundamental frequency of the speech, is treated to reduce the effect of noise on the speech by deriving from the pulse train the mean value of the pulse spacing over a predetermined time interval and transmitting a pulse at this pulse spacing. The process is repeated for successive time intervals, each time interval commencing at a time after the commencement of the preceding time interval which is equal to the pulse spacing derived during the preceding time interval. The mean pulse spacing may be obtained by weighting each pulse spacing in the incoming signal in accordance with the time of occurrence of the pulse after the commencement of the interval, adding the weighted pulse spacings, and dividing the sum by a suitable factor. The Figure shows an excitation function generator for a vocoder in which the incoming speech is applied via a non-linear circuit NLG and a filter BP to a zero crossing detector ND and a pulse shaper IF to produce a pulse at every zero crossing in one direction of the fundamental frequency of the speech. The speech is also applied to a voiced-unvoiced detector D the output of which operates gates T1 and T2 so that during unvoiced sounds, when the excitation pulses are randomly spaced, the excitation pulses are fed direct to the output ANK 1 while during voiced sounds the pulses are fed to the units 1 to IV in order to derive the mean pulse spacings in accordance with the invention. The unit I comprises a device which measures the spacing between each pair of excitation pulses and stores these measured pulse spacings. The unit II then sums these pulse spacings over a measured interval, weighted in accordance with the time of occurrence after the start of the time interval if required, and divides them by the number of pulses, or some function thereof, to obtain the mean pulse spacing which is used in unit IV to generate the output excitation function pulse train. It is stated that the arrangement introduces some degradation into speech signals but may be advantageous under noisy conditions.

公开(公告)号：GB1124171A

公开(公告)日：1968-08-21

申请号：GB25566

申请日：1966-01-04

Applicant: IBM

Inventor： PAULUS ERWIN

IPC: H03M1/44 ,  H03M1/00

Abstract: 1,124,171. Analogue to digital converters. INTERNATIONAL BUSINESS MACHINES CORP. 4 Jan., 1966 [20 Jan., 1965], No. 255/66. Heading G4H. An analog-to-digital converter comprises a number of series connected stages each associated with a digit of a binary number, each stage comprising an amplifier, a switch being arranged either to connect the amplifier to the next stage or to connect a by-pass circuit to the next stage, the amplification of each stage being twice the amplification factor, measured in decibels of the next. The converter comprises three stages having amplifiers V1, V2, V3 the outputs being applied to threshold circuits for comparison with a reference signal R. If this is exceeded the corresponding switches S1 1 , S3 1 operates and by-passes the amplifier. The switches also give digital output signals. The series connection causes the gains to be multiplied and since the amplification factors measured in dbs are related in the proportion 1, 2, 4 the binary number represented by the digital output is the logarithm of the input analogue signal. The threshold devices may be Schmitt triggers, and the switches may be replaced by a gating circuit (Fig. 4, not shown)

公开(公告)号：GB1120706A

公开(公告)日：1968-07-24

申请号：GB1655266

申请日：1966-04-15

Applicant: IBM

Inventor： ROTHAUSER ERNST ,  PAULUS ERWIN ,  EUFELHART NORBERT

IPC: H04B1/66

Abstract: 1,120,706. Vocoder. INTERNATIONAL BUSINESS MACHINES CORP. 15 April, 1966 [26 April, 1965], No. 16552/66. Heading H4R. A channel vocoder which includes a number of band-pass filters to derive signals defining the spectrum of a speech signal has an integrator arranged on the output of each band-pass filter with the integration time of each integrator controlled in accordance with the pitch frequency of the input speech signal. The arrangement eliminates pitch frequency dependence of the various analysis channel outputs. Fig. 2 shows a system in which the speech spectrum is analysed by band-pass filters BP 1 to BP n whose outputs are rectified and integrated in circuits I 1 to I n to provide signals defining the speech spectrum. The integrators are sampled and reset by pulses on line K o , the pulses being derived from the speech pitch pulses during voiced sounds and from a constant repetition rate pulse generator IG during unvoiced sounds, switching being under the control of a voiced-unvoiced discriminator D1. In a vocoder where the excitation function is derived as a pulse train, both during voiced and unvoiced sounds, the pulses being randomly spaced within limits during unvoiced sounds, the excitation function pulses may be used to sample and discharge the integrator both during voiced and unvoiced sounds, Fig. 3 (not shown). Where the spectrum signals are to be transmitted in digital form an arrangement such as is shown in Fig. 5 may be used where the integrator has a threshold discriminator D 1 to D 1 connected to reset the integrator when the integrator output reaches a predetermined value. Each resetting produces a pulse on line e and these pulses are counted by the respective counter BZ 1 to BZ n . Each excitation function pulse is applied to store the counter count and to reset the counter to zero. If the spectrum signals are to be quantized, e.g., to eight levels, the integrator and level discriminator may be arranged so that it produces a maximum of 8 pulses on line e for the maximum signal level during the longest expected excitation function period. By using a three-stage binary counter for each counter BZ 1 to BZ n a binary signal is obtained directly from the state of the binary counters. Excitation function pulses may be derived as shown from the speech signal during both voiced and unvoiced sounds, or the resetting pulses may be derived from an idependent generator during unvoiced sounds as in Fig. 2 (or Fig. 4, not shown). Transistor integrator circuits are described, Figs. 6 and 7 (not shown).

公开(公告)号：CA786484A

公开(公告)日：1968-05-28

申请号：CA786484D

Applicant: IBM

Inventor： PAULUS ERWIN ,  ENZERSDORF MARIA

公开(公告)号：CA773268A

公开(公告)日：1967-12-05

申请号：CA773268D

Applicant: IBM

Inventor： BANDAT KURT ,  ROTHAUSER ERNST ,  PAULUS ERWIN

公开(公告)号：FR1424639A

公开(公告)日：1966-01-14

申请号：FR3424

申请日：1965-01-27

Applicant: IBM

Inventor： ROTHAUSER ERNST ,  PAULUS ERWIN

IPC: H03K7/02