Marvin E Frerking

6545550, Apr 8, 2003

Apr 13, 2001

09/833983

Marvin E. Frerking - Cedar Rapids IA, 52402

G01R 2300

331 44, 331162

A means is provided to estimate the amount of frequency deviation experienced in a precision resonator resulting from the effects of previous thermal history, acceleration, or aging by determining the differential effect of the perturbing condition on different resonant modes in the same resonator or on different resonators exposed to the same environment. The measurements may be made simultaneously, or sequentially against an independent frequency source. Residual frequency hysteresis effects may be determined in connection with an independent temperature sensor if the exact temperature in not known.

6977557, Dec 20, 2005

Mar 25, 2004

10/807788

Marvin Elmer Frerking - Cedar Rapids IA, US

H03B005/32
H03B005/36

331173, 331 55, 331158, 331172

A means is provided to establish oscillations on a particular mode or resonance of a quartz crystal in a crystal oscillator and to discriminate against other modes. This is done by injecting a signal close in frequency to the desired mode until oscillation have been established and saturation of the active element has occurred. The limiting process then discriminates against the unwanted modes and holds the oscillation on the desired mode.

45132593, Apr 23, 1985

Dec 23, 1982

6/452641

Marvin E. Frerking - Cedar Rapids IA

Rockwell International Corporation - El Segundo CA

H03L 100

331176

A closed loop frequency source includes a controllable oscillator that provides a first frequency source, a reference oscillator that provides a second signal, and a comparator that compares the two frequencies to provide an error signal that represents the difference between the frequencies. The error signal is used by an error signal generator to generate a compensation signal which offsets the carrier frequency that drives an output device such as a time-of-day clock so that the output device automatically gains or loses the previously accumulated time error without the necessity of being periodically updated.

48916110, Jan 2, 1990

Mar 9, 1989

6/321490

Marvin E. Frerking - Cedar Rapids IA

Rockwell International Corporation - El Segundo CA

H03B 504
H03B 532

331158

In order to compensate for mechanical vibration that corrupts the RF output spectrum of a crystal oscillator, three accelerometers are mounted with the oscillator and aligned on mutually perpendicular axes. The outputs of the accelerometers are digitized and applied to adaptive transversal filters comprising a digital signal processor. The crystal oscillator is placed on a vibration table and its output is compared with an external frequency reference. The tap weights of the filters are then optimized so that the vibration components of the output spectrum of the oscillator are minimized. After the tap weights of the filters are determined and fixed, the filters provide vibration compensation for the oscillator. During operation of the crystal oscillator, the outputs of the filters are summed and applied to a varactor in the oscillator to compensate the output for the effects of mechanical vibration.

41268539, Nov 21, 1978

Sep 16, 1977

5/833857

Marvin E. Frerking - Cedar Rapids IA

Rockwell International Corporation - El Segundo CA

H03K 1320

340347DA

Non-linear digital-to-analog conversion is performed by employing a plurality of counting rates and counting intervals in a digital counter to generate a variable width pulse, the width of which determines the desired analog value corresponding to the digital value to be converted.

39784126, Aug 31, 1976

May 2, 1975

5/574054

Marvin E. Frerking - Cedar Rapids IA

Rockwell International Corporation - El Segundo CA

H04B 116

325478

Noise suppression in a radio receiver is accomplished by clamping the receiver detector output for a predetermined period each time the noise content in the receiver signal exceeds some predetermined threshold value.

49069446, Mar 6, 1990

Aug 17, 1988

7/233694

Marvin E. Frerking - Cedar Rapids IA

Rockwell International Corporation - El Segundo CA

H01L 102
H01L 700
H01L 706
H01L 708

331 1A

A time compensated clock oscillator (TCCO) is provided with an integrator to produce stability of the output frequency. The integrator is connected between the D/A converter and the voltage controlled crystal oscillator (VCXO) of the TCCO. The output frequency of the VCXO is fed back to a frequency counter, which samples the output, determines its average frequency, and compares it with a reference frequency. A microprocessor corrects the reference frequency for temperature changes, determines the output frequency error, calculates the output frequency drift rate, and provides a digital correction signal. The D/A converter converts the digital correction signal to an input voltage for the integrator. The integrator produces a ramp-shaped control voltage for input to the VCXO. Because the control voltage produced by the integrator changes smoothly over the interval between samples by the frequency counter, the output frequency drift rate of the VCXO is continuously corrected to produce improved short-term frequency stability.

43050417, Dec 8, 1981

Oct 26, 1979

6/088732

Marvin E. Frerking - Cedar Rapids IA

Rockwell International Corporation - El Segundo CA

H03K 526

328155

A time compensated clock oscillator is disclosed that has a first low power oscillator that drives an output device such as a time-of-day clock, a second more precise oscillator whose output is compared to the output of the first oscillator, and develops a correction signal that is used to periodically correct the output device.