Abstract: The remote control unit has a selection mechanism for selecting any one of a number of categories of equipment to be controlled. The commands available for keyboard input in any given category are automatically displayed to the user upon selection of the category. Switches are provided for user selection of the model number of any one of a number of manufacturers of the equipment within the category to be controlled. Operation of the switches allows program controlled read-outs of formats stored in memory. An infra-red LED is then energized in accordance with the format to transmit the signal to the unit to be controlled.

Abstract: A remote control unit responds to activation of a "identify" button by transmitting a sequence of command signals, each of the same command in a different format. Since the appliance to be controlled is turned on, it responds in a predetermined way (e.g. a channel change) when it receives the properly formatted command. The user then terminates the learn mode and a pointer denoting the address of the last transmitted command, i.e. the properly formatted command, is stored in the unit and used as part of the address for reading data for subsequent user-selected commands out of memory.

Abstract: Trigger signals both at horizontal and vertical line frequency required for an oscilloscope are derived from the horizontal synchronization output stage of a television receiver without any direct electrical connection to the receiver. A pick-up coil or tuned pick-up circuit is positioned in the vicinity of the receiver. The signals induced in the coil or circuit are applied to a comparator. The output of the comparator is at the required TTL level to provide the horizontal trigger to the oscilloscope. If a vertical trigger is also required, the comparator output is applied to a frequency doubler circuit. The output of the frequency doubler circuit is divided by 525, the so-divided output constituting vertical trigger circuits for the oscilloscope. A monitoring circuit for horizontal sync signals is connected to the comparator output and indicates the presence of horizontal sync signals by activation of a light emitting diode.

Abstract: In a color picture projection system three monochrome pictures are superimposed to form a color display on a projection screen by means of a chromatic projection lens system in each of three channels. Each channel has a reflector to fold the light path. Since at least one monochrome picture (e.g. the blue picture) includes radiation within a desired band of wavelengths corresponding to its associated color and radiation outside of this desired band, the reflector in this channel is wavelength-selective and reflects only the radiation within the desired band towards the projection screen. The undesired radiation is transmitted through the reflector so that it does not reach the projection screen. Achromatic lenses are therefore not required.

Abstract: A motorized drawer is moved from a fully closed to a fully open position, or vice versa, in response to user activation of a single pole double throw switch. The motor moving the drawer is connected to the user activated control switch and to a limit switch. Whenever the drawer reaches one of the end positions, a limit switch opens the circuit through which the motor was energized to move the drawer to that position. At the same time, the limit switch partially completes the circuit for energizing the motor in the opposite direction. The latter circuit is completed when the user again activates the control switch, i.e. completes the circuit allowing current flow through the motor in the direction required to drive the drawer to the other end.