Fred A Johnson

US Patent:

43097189, Jan 5, 1982

Filed:

Sep 22, 1980

Appl. No.:

6/189498

Inventors:

Fred D. Johnson - Evanston IL

Assignee:

Zenith Radio Corporation - Glenview IL

International Classification:

H04N 962

US Classification:

358 10

Abstract:

A service switch arrangement for a color television receiver having a low level matrixing system developing red, blue and green color signals includes a service switch having a normal position and a service position. In the normal position of the switch, a video output amplifier is enabled for coupling the red, blue and green color signals to the electron gun cathode elements of a color cathode ray tube. In the service position of the switch, the video output amplifier is disabled while an independently generated DC control voltage is coupled to the electron gun cathode elements for facilitating adjustment of the cut-off points of the cathode elements.

US Patent:

43706746, Jan 25, 1983

Filed:

Mar 3, 1981

Appl. No.:

6/239969

Inventors:

Fred D. Johnson - Evanston IL
Michael D. Flasza - Schaumburg IL
Wayne E. Bretl - Schaumburg IL

Assignee:

Zenith Radio Corporation - Glenview IL

International Classification:

H04N 916

US Classification:

358 74

Abstract:

A stabilization network is disclosed which compensates for variable emission characteristics of a cathode in a television receiver's cathode ray tube. During the receiver's vertical interval, a variable gain video amplifier applies a black level D. C. voltage to the cathode. The resulting cathode current is sensed and compared to a low level reference current. If the cathode current does not equal the reference current, a control signal is applied to the amplifier. The amplifier responds to changing its D. C. output voltage until the cathode current is equal to the reference current. The amplifier also responds to the control signal by altering its gain so that, when a video signal is received, the cathode develops peak white currents of a given value in response to peak white portions of the video signal.

US Patent:

43908179, Jun 28, 1983

Filed:

Feb 27, 1981

Appl. No.:

6/238771

Inventors:

Fred D. Johnson - Evanston IL

Assignee:

Zenith Radio Corporation - Glenview IL

International Classification:

H01J 2970
H01J 2972

US Classification:

315384

Abstract:

An integratable CRT spot cut-off network is described for use in a television receiver. The network establishes a reference current for biasing up the receiver's G. sub. 1 grid when the supply voltage comes up, and a bypass capacitor coupled to the grid charges toward the supply voltage. When the receiver is turned off, the network terminates the reference current as the supply voltage starts to collapse and prevents the bypass capacitor from discharging. The charge stored on the capacitor reverse biases the grid to cut off the receiver's beam current.

US Patent:

42745322, Jun 23, 1981

Filed:

Jul 26, 1979

Appl. No.:

6/061651

Inventors:

Fred I. Johnson - Elmhurst IL

International Classification:

B65G 3700
B65G 2504
B65G 4731

US Classification:

198429

Abstract:

A can handling system for transporting cans with an open end through an oven for drying of printed material applied to the exterior of the can comprising, a plurality of free-standing can carriers, each having a base and an upstanding member centrally thereof to engage within a can and hold a can in inverted position and with the base and upstanding member being of a size to position a can to prevent contact between two cans when a pair of can-carrier bases are in contact, transport structure for advancing cans sequentially at uniformly spaced intervals to a loading station, conveying and synchronizing structure for advancing can carriers sequentially to said loading station to have the can engaging members of the can carriers at the same spacing as the cans arriving at the loading station whereby cans may be transferred sequentially to sequential can carriers, and conveyor structure for conveying the can carriers to an oven in single-file relation and thereafter moving the can carriers and cans through the oven in successive transverse rows and after movement through the oven to an unloading station where the cans are removed from the can carriers.

US Patent:

48252948, Apr 25, 1989

Filed:

Oct 7, 1987

Appl. No.:

7/106078

Inventors:

Fred D. Johnson - Evanston IL

Assignee:

Zenith Electronics Corporation - Glenview IL

International Classification:

H04N 568

US Classification:

358243

Abstract:

An RGB video output drive amplifier is provided with current limiting circuitry at the base of the driver circuit. In a preferred embodiment, the driver circuit comprises a drive transistor with associated biasing circuits. The base of the drive transistor is coupled to a current limiting circuit to shunt excess current from the base of the transistor and to block additional input current at or near the level representative of the driver transistor reaching its saturation mode. Excess current is dissipated through associated resistance in the base circuit and while diode means prevent high input signals from driving the drive transistor into saturation. Maintaining the drive transistor at or below its saturation level pevents flaring in the resulting video picture display. No appreciable storage charge is built up during the short periods which the drive transistor may enter saturation in response to rapid transients provided through a transient response circuit in parallel with the current limiting circuit. Detail in the resulting picture is optimized and minimal additional capacitance is added to the output circuitry.

US Patent:

44464436, May 1, 1984

Filed:

May 20, 1982

Appl. No.:

6/379838

Inventors:

Fred D. Johnson - Evanston IL
Michael D. Flasza - Schaumburg IL
George J. Tzakis - Glenview IL

Assignee:

Zenith Radio Corporation - Glenview IL

International Classification:

H03F 345
H03F 326
H04N 544

US Classification:

330257

Abstract:

An integratable amplifier is disclosed for developing a high level output signal with reduced power dissipation. The amplifier includes a first circuit (108, 110) which responds to an input signal for developing first and second signal currents whose amplitudes increase and decrease, respectively, in response to an input signal transition of a given direction. A second circuit (32a) receives the first signal current for establishing a third signal current which mirrors the first signal current. The second and third signal currents are received by a third circuit (70a) for conversion thereof to an amplified output signal. To stabilize the gain of the amplifier, a negative feedback path (50a) is coupled between the input signal and the output signal.

US Patent:

43475280, Aug 31, 1982

Filed:

Mar 16, 1981

Appl. No.:

6/244422

Inventors:

Fred D. Johnson - Evanston IL
George J. Tzakis - Glenview IL

Assignee:

Zenith Radio Corporation - Glenview IL

International Classification:

H04N 962
H04N 920

US Classification:

358 10

Abstract:

A circuit is disclosed for establishing proper video output voltages in a color television receiver prior to setting the receiver's G2 voltage. In the preferred embodiment, the circuit includes three emitter follower stages, each coupled to the output of a video amplifier. The collectors of the emitter follower stages are coupled to a supply voltage through a common resistance. A two position switch is connected across the common resistance such that, during normal receiver operation, closure of the switch shunts the common resistance. When G2 set-up is to be effected, the switch is opened so that a predetermined voltage is dropped across the common resistance and the three emitter follower stages have similar, predetermined D. C. output voltages.