Howard F Jirka

44020392, Aug 30, 1983

Sep 3, 1981

6/299156

Howard F. Jirka - Crystal Lake IL

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

H02M 3335

363 21

A floating, constant power, battery feed circuit wherein a single transformer is used to perform the functions of battery feed and audio coupling. AC feedback is used to control the dynamic output impedance of the circuit. To achieve a constant dynamic output impedance, the amount of AC feedback is controlled by the DC output voltage, which in turn depends on the loop resistance. To achieve a constant audio gain from the switching network to the subscriber set, the audio signal from the switching network is multiplied by a signal representing the DC output voltage.

47806966, Oct 25, 1988

Sep 26, 1986

6/911817

Howard F. Jirka - Crystal Lake IL

American Telephone and Telegraph Company, AT&T Bell Laboratories - Murray Hill NJ

H01F 2728
H01F 1104
H01B 1300

336170

A multifilar transformer apparatus and winding method where first and second windings are bifilar wound around a core for NA turns, the first, second, third, and fourth windings are quadfilar wound around the core for NB turns, and the first and second windings are again bifilar wound around the core for NC turns. Winding symmetry is preserved and a turns ration of (NA+NB+NC):2NB is achieved.

46791329, Jul 7, 1987

Aug 8, 1985

6/763668

Howard F. Jirka - Crystal Lake IL

American Telephone and Telegraph Company, AT&T Bell Laboratories - Murray Hill NJ

H02M 3335

363 21

A substantial reduction in the common-mode noise generated by a switching-mode power converter is achieved by incorporating a multifilar-wound transformer into the converter in such manner that the inter-winding capacitances cause a cancellation of common-mode, noise components at the converter output.

40806286, Mar 21, 1978

Mar 14, 1977

5/777374

Howard F. Jirka - Mount Prospect IL

Zenith Radio Corporation - Glenview IL

H04N 568

358166

A color television receiver includes well-known circuitry for detection and display of a received broadcast signal. Image enhancement means produce an expanded element luminance signal. A differentiating network produces the derivative of the expanded-element signal and a differential amplifier couples the derivative signal in a "push-pull" fashion to a pair of electrostatic deflection plates which influence the horizontal scansion of the receiver. A method of image enhancement as well as derivative processing and signal delay structures are shown.

39353842, Jan 27, 1976

Jan 2, 1975

5/537865

Howard F. Jirka - Mount Prospect IL

Zenith Radio Corporation - Chicago IL

H04N 514

178 75R

A low cost network for use in a television receiver for receiving a video signal and generating therefrom both a control signal for modulating the scan velocity of a CRT electron beam and a delayed video signal for intensity modulating the CRT electron beam with picture information. The network uses only one delay line for generating the control signal and the delayed video signal. A video signal is applied to an impedance means followed by a delay means coupled to a reflecting termination. The impedance of the impedance means is substantially equal to the characteristic impedance of the delay means. An output terminal from which the control signal is taken is included at a point between the impedance means and the delay means. The delayed video signal is generated by means responsive to the signal received by the reflecting termination from the delay means. The network may also be used to generate preshoot and overshoot peaking components for peaking the delayed video signal.

43409067, Jul 20, 1982

May 14, 1980

6/149708

Pieter den Toonder - Dordrecht, NL
Johannes C. Seltenrijch - Gorichem, NL
Graham S. Stubbs - Poway CA
Pieter J. Fondse - Papendrecht, NL
Howard F. Jirka - Crystal Lake IL

Oak Industries Inc. - Rancho Bernardo CA

H04N 716

358124

A method and means for coding and decoding video signals by repetitive video signal polarity reversal includes the steps of comparing the brightness level of a predetermined time period of the video signal with the brightness level of the video signal over the previous predetermined time period. The polarity of the video signal is inverted or reversed if the difference in brightness level between successive predetermined time periods exceeds a given value.

39368696, Feb 3, 1976

Nov 2, 1973

5/412220

Howard F. Jirka - Mount Prospect IL

Zenith Radio Corporation - Chicago IL

H04N 9535

358 27

A color television receiver includes an automatic chroma control (ACC) system and a switch selectable manual color level potentiometer and a closed loop automatic color level limiter (ACL) with a preset color level potentiometer. The ACL loop is of the sample-and-hold type and includes a peak detector for detecting chroma signals in excess of a predetermined threshold level and a transistor for controlling the preset color level potentiometer for adjustment of the chroma amplifier gain. A relatively small capacitor is connected across the collector and base of the transistor and, in conjunction with a bias resistor, presents a relatively long time constant by reflecting a magnified input capacitance between its base and emitter electrodes due to the Miller effect. In the event the transistor is driven to cutoff during periods when the switch is in the manual position, the input capacitance is very small enabling the ACL circuit to recover quickly.