Joseph H Rothweiler

US Patent:

50125184, Apr 30, 1991

Filed:

Aug 16, 1990

Appl. No.:

7/570126

Inventors:

Yu J. Liu - Wharton NJ
Joseph Rothweiler - Cranford NJ

Assignee:

ITT Corporation - New York NY

International Classification:

G10L 500

US Classification:

381 42

Abstract:

A speech coder employs vector quantization of LPC parameters, interpolation, and trellis coding for improved speech coding at low bit rates (400 bps). The speech coder has an LPC analysis module for converting input speech to LPC parameters, an LSP conversion module for converting LPC parameters into line spectrum frequencies (LSP) data, and a vector quantization and interpolation (VQ/I) module for encoding the LSP data into vector indexes for transmission by applying LPC spectral amplitude as weighting coefficients to the LSP data. The VQ/I module outputs one vector index for every two LPC frames in order to reduce the transmission bit rate, and the omitted frames are interpolated on the receiving end. A decoder correspondingly decodes incoming indexes to LPC parameters and synthesizes them into output speech. Trellis coders with an adaptive tracking function encode the pitch and gain parameters of the LPC frames.

US Patent:

56490518, Jul 15, 1997

Filed:

Jun 1, 1995

Appl. No.:

8/486130

Inventors:

Joseph Harvey Rothweiler - Ellicott City MD
John Charles Carmody - Ellicott City MD
Srinivas Nandkumar - Columbia MD

International Classification:

G10L 900

US Classification:

395 231

Abstract:

A speech signal has its characteristics extracted and encoded (16), transmitted over a limited-data-rate path (18) and is decoded (20) and synthesized (22) at the receiving end. The characteristics include line spectral frequencies (LSF), pitch and jitter. The LSF are extracted by autoregression, and split-vector quantized (SVQ) in a single frame, and, in parallel, in blocks of two, three and four frames. The SVQ codes have equal length and are evaluated for distortion in conjunction with a threshold. The threshold is varied in such a manner as tend to select for transmission those codewords which maintain a constant data rate into a transmit buffer. A single-bit jitter bit, and encoded pitch value, are product coded with the selected LSF codeword, and all are transmitted over the data path (18) to the receiver. The receiver decodes the characteristics, and controls a pitch generated (1226) in response to the pitch value and a random pitch jitter in response to the jitter bit. Two sets of line spectrum filters receive random noise and the pitch signal, respectively.

US Patent:

56689250, Sep 16, 1997

Filed:

Jun 1, 1995

Appl. No.:

8/482322

Inventors:

Joseph Harvey Rothweiler - Ellicott City MD
John Charles Carmody - Ellicott City MD
Srinivas Nandkumar - Columbia MD

Assignee:

Martin Marietta Corporation - Bethesda MD

International Classification:

G10L 900

US Classification:

704220

Abstract:

A speech signal has its characteristics extracted and encoded (16), transmitted over a limited-data-rate path (18) and is decoded (20) and synthesized (22) at the receiving end. The characteristics include line spectral frequencies (LSF), pitch and jitter. The LSF are extracted by autoregression, and splitvector quantized (SVQ) in a single frame, and, in parallel, in blocks of two, three and four frames. The SVQ codes have equal length and are evaluated for distortion in conjunction with a threshold. The threshold is varied in such a manner as tend to select for transmission those codewords which maintain a constant data rate into a transmit buffer. A single-bit jitter bit, and encoded pitch value, are product coded with the selected LSF codeword, and all are transmitted over the data path (18) to the receiver. The receiver decodes the characteristics, and controls a pitch generated (1226) in response to the pitch value and a random pitch jitter in response to the jitter bit. Two sets of line spectrum filters receive random noise and the pitch signal, respectively.

US Patent:

46912924, Sep 1, 1987

Filed:

Apr 13, 1983

Appl. No.:

6/484526

Inventors:

Joseph H. Rothweiler - Bloomfield NJ

Assignee:

RCA Corporation - Princeton NJ

International Classification:

G06F 738

US Classification:

364724

Abstract:

A digital filter system in which the frequency spectrum of an input signal is divided into M consecutive subbands. Each subband is generated by multiplying the impulse reponse of a low pass filter by a sinusoid (sine or cosine) whose frequency is equal to the center frequency of its respective subband. The sinusoids of adjacent bands are phase shifted by 90. degree. relative to each other to establish a condition enabling aliasing components to be cancelled when the subbands are recombined.

US Patent:

49759566, Dec 4, 1990

Filed:

Jul 26, 1989

Appl. No.:

7/385644

Inventors:

Yu J. Liu - Wharton NJ
Joseph Rothweiler - Cranford NJ

Assignee:

ITT Corporation - New York NY

International Classification:

G10L 500

US Classification:

381 36

Abstract:

A speech coder employs vector quantization of LPC parameters, interpolation, and trellis coding for improved speech coding at low bit rates (400 bps). The speech coder has an LPC analysis module for converting input speech to LPC parameters, an LSP conversion module for converting LPC parameters into line spectrum frequencies (LSP) data, and a vector quantization and interpolation (VQ/I) module for encoding the LSP data into vector indexes for transmission by applying LPC spectral amplitude as weighting coefficients to the LSP data. The VQ/I module outputs one vector index for every two LPC frames in order to reduce the transmission bit rate, and the omitted frames are interpolated on the receiving end. A decoder correspondingly decodes incoming indexes to LPC parameters and synthesizes them into output speech. Trellis coders with an adaptive tracking function encode the pitch and gain parameters of the LPC frames.