David L Sanders

US Patent:

44853580, Nov 27, 1984

Filed:

Sep 28, 1981

Appl. No.:

6/306507

Inventors:

Carl F. Andren - Indiatlantic FL
William H. Mosley - St. Petersburg FL
David E. Sanders - Kenneth City FL

Assignee:

E-Systems, Inc. - Dallas TX

International Classification:

H03C 300

US Classification:

332 23R

Abstract:

A method and apparatus for phase modulating a carrier signal to convey an information signal (12) such that the carrier signal has a constant amplitude envelope. A Hilbert transform signal (14) of the information signal (12) is produced. The signals (12, 14) are sampled to produce signals (16, 18), which represent cartesian coordinate values. The cartesian coordinate values are then converted into equivalent polar vectors (20-36) which have both an amplitude (R) and an angle (. theta. ). The polar vector quantity (R,. theta. ) is converted into two unity amplitude vectors (A, B). The unity amplitude vectors (A, B) are offset from the polar vector quantity by an angle the cosine of which is proportional to the amplitude of the polar vector (R). The carrier signal is sequentially phase modulated by each of the angles of the unity amplitude vectors (A, B) for each sample period of the information signal. This modulation procedure maintains a constant amplitude envelope for the carrier signal and makes possible simultaneous demodulation of a plurality of carrier signals in a single demodulation channel.

US Patent:

45090173, Apr 2, 1985

Filed:

Feb 15, 1984

Appl. No.:

6/580426

Inventors:

Carl F. Andren - Indiatlantic FL
William H. Mosley - St. Petersburg FL
David E. Sanders - Kenneth City FL

Assignee:

E-Systems, Inc. - Dallas TX

International Classification:

H03D 300
H04L 2722

US Classification:

329105

Abstract:

A method and apparatus for phase modulating a carrier signal to convey an information signal (12) such that the carrier signal has a constant amplitude envelope. A Hilbert transform signal (14) of the information signal (12) is produced. The signals (12, 14) are sampled to produce signals (16, 18), which represent cartesian coordinate values. The cartesian coordinate values are then converted into equivalent polar vectors (20-36) which have both an amplitude (R) and an angle (. theta. ). The polar vector quantity (R,. theta. ) is converted into two unity amplitude vectors (A, B). The unity amplitude vectors (A, B) are offset from the polar vector quantity by an angle the cosine of which is proportional to the amplitude of the polar vector (R). The carrier signal is sequentially phase modulated phase angles of the unity amplitude vectors (A, B) for each sample period of the information signal. This modulation procedure maintains a constant amplitude envelope for the carrier signal and makes possible simultaneous demodulation of a plurality of carrier signals in a single demodulation channel.

US Patent:

43807372, Apr 19, 1983

Filed:

Nov 12, 1980

Appl. No.:

6/206073

Inventors:

David E. Sanders - Kenneth City FL

Assignee:

E-Systems, Inc. - Dallas TX

International Classification:

H03G 320

US Classification:

330134

Abstract:

A fast slew rate automatic gain control circuit (10) includes a variable gain amplifier (14) which is responsive to a gain control signal and an amplitude detector (18) which produces an amplitude signal corresponding to the amplitude of the received signal transmitted through amplifier (14). The amplitude signal is provided to the input node of a loop filter (24) and to the inputs of threshold detectors (30, 32). Positive and negative slew threshold circuits (34, 38) provide threshold signals respectively for the threshold detector circuits (30, 32). When the amplitude signal is within the range of the threshold signals the loop filter produces the gain control as the function of the amplitude signal. When the amplitude signal is less than the positive slew threshold signal the threshold detector (32) produces a drive signal which is provided to the loop filter (24) and causes the generation of the gain control signal to have an accelerated positive slew rate which increases the gain. When the amplitude signal exceeds the negative slew threshold signal the threshold detector (30) produces a drive signal which is supplied to the loop filter (24).