Francis H Hilbert

US Patent:

43777287, Mar 22, 1983

Filed:

Mar 4, 1981

Appl. No.:

6/240445

Inventors:

Francis H. Hilbert - Addison IL

Assignee:

Motorola Inc. - Schaumburg IL

International Classification:

H04H 500
H03D 318

US Classification:

179 1GS

Abstract:

The circuit determines whether an incoming frequency is within the normal "lock-in" range of a phase locked loop VCO or not, and whether it is higher or lower than the VCO frequency. If not within normal range, the beats are rectified and gated to provide a DC control voltage of the proper value and polarity for locking the oscillator on the incoming frequency. Rectification may be half or full wave as needed, and the circuit may include filter bandwidth control as well. This circuit is suitable for signals of any waveform, quadrature signals, and AM stereophonic signals.

US Patent:

41646231, Aug 14, 1979

Filed:

Nov 17, 1977

Appl. No.:

5/852272

Inventors:

Francis H. Hilbert - Addison IL
Norman W. Parker - Wheaton IL

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04H 500

US Classification:

179 1GS

Abstract:

An AM receiver for receiving a compatible stereo signal and requiring a dynamic correction factor prevents the introduction of a false phase reference signal by limiting and filtering the signal going into the oscillator of the PLL which provides the correction reference signal.

US Patent:

40515320, Sep 27, 1977

Filed:

Jun 19, 1975

Appl. No.:

5/588250

Inventors:

Francis H. Hilbert - Addison IL
Theodore S. Rzeszewski - Lombard IL

Assignee:

Matsushita Electric Company of America - Franklin Park IL

International Classification:

H04N 708

US Classification:

358142

Abstract:

A low level video auxiliary signal is transmitted in addition to the conventional composite black and white or color television signal. The auxiliary signal is in the form of redundant, opposite-polarity signal portions during pairs of time successive signal portions, such as horizontal lines or fields of the composite television signal. The auxiliary signal also may be transmitted in the form of a predetermined frequency with the auxiliary information on successive lines of the composite television signal being out of phase by one-half the period of the auxiliary signal frequency. When the composite signal is detected and displayed by the conventional circuitry in the receiver, the auxiliary information is visually cancelled in the image displayed on the cathode ray tube and the normal video information is displayed. Additional circuitry is employed in the receiver to effect cancellation of the conventional video information from the display and to reinforce successive portions of the auxiliary signal; so that the auxiliary signal is displayed on the cathode ray tube of the receiver when desired.

US Patent:

41729668, Oct 30, 1979

Filed:

Feb 23, 1978

Appl. No.:

5/880686

Inventors:

Norman W. Parker - Wheaton IL
Francis H. Hilbert - Addison IL

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04H 500

US Classification:

179 1GS

Abstract:

An AM receiver for utilizing a broadcast signal of the form (1+L+R) cos (. omega. sub. c t+. phi. ) separates the L and R signals by utilizing phase detection and matrixing. Distortion is either eliminated with non-linear amplification or reduced with partial matrixing.

US Patent:

41929683, Mar 11, 1980

Filed:

Sep 27, 1977

Appl. No.:

5/837258

Inventors:

Francis H. Hilbert - Addison IL
Norman W. Parker - Wheaton IL

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04H 500

US Classification:

179 1GS

Abstract:

An improved AM stereo receiver for receiving broadcast signal having the form (1+L+R)cos(. omega. sub. c t+. phi. ) where. phi. is arc tan(L-R)/(1+L+R). The sum signal (L+R) is demodulated in an envelope detector and coupled to a matrix. The uncorrected difference signal is demodulated in a synchronous detector, a corrector circuit derives the correction factor, and a divider circuit provides the corrected difference signal. During tuning, and until a PLL is locked on the carrier frequency, the receiver is locked into the monophonic mode and tuned on the monophonic signal. When the PLL locks, the difference signal is coupled through to the matrix for stereophonic mode operation.

US Patent:

44069227, Sep 27, 1983

Filed:

Aug 21, 1981

Appl. No.:

6/295185

Inventors:

Norman W. Parker - Wheaton IL
Francis H. Hilbert - Addison IL

Assignee:

Motorola Inc. - Schaumburg IL

International Classification:

H04H 500

US Classification:

179 1GS

Abstract:

The signal transmitted is a compatible amplitude modulated carrier with amplitude directly proportional to the monaural information or 1+L+R up to a frequency near the upper end of the normal program spectrum. Above the transition region, the amplitude becomes a pure quadrature function. The instantaneous phase varies as a function of the quadrature phase relationship. Transmitter and receiver embodiments are disclosed.

US Patent:

41593987, Jun 26, 1979

Filed:

Sep 27, 1977

Appl. No.:

5/837256

Inventors:

Francis H. Hilbert - Addison IL
Norman W. Parker - Wheaton IL

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04H 500

US Classification:

179 1GS

Abstract:

In an AM broadcast transmitter, an infrasonic tone is added to the difference channel of a compatible AM stereo system to provide a stereo presence signal. In a stereophonic receiver, the corrected output of a synchronous detector in the difference signal channel is coupled to an infrasonic detector for control of a mono/stereo mode switch and a stereo presence indicator. When the received signal is weak, the infrasonic tone is effectively stronger, because the phase angle is increased. Since the s/n ratio is proportional to the phase angle, the stereo presence signal is self-adjusting. The mode switch and indicator are enabled for all values of L and R. The infrasonic tone could also be removed from the transmitted signal whenever the difference signal goes above a predetermined level during stereo broadcasting, in which case a comparator at the receiver would enable the mode switch and indicator upon detection of either a difference signal or the infrasonic tone.

US Patent:

43717470, Feb 1, 1983

Filed:

Mar 24, 1980

Appl. No.:

6/133189

Inventors:

Francis H. Hilbert - Addison IL

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04H 500

US Classification:

179 1GS

Abstract:

A decoder for use with a compatible AM stereophonic signal utilizes a amplifier and a feedback loop from the amplifier output to control the output of a multiplier circuit which is one input to the amplifier. The amplifier output is thus forced to become the required correction factor used in restoring the stereo program signals.