Abstract: An amplifier including an in phase feedback signal to therefore exhibit negative resistance is receptive of an input alternating signal which includes a frequency F. The output of the amplifier is coupled to a resonator adjusted to a center frequency F and having undesirable resistance which is offset by the negative resistance of the amplifier. The resonator includes an inductor and adjustable capacitor arranged either in series or in parallel with the amplifier to therefore change the value of F.

Abstract: An attitude control system for spacecraft having thrusters utilizes the exhaust plume of the thrusters for attitude control. At least one of the thrusters is canted so that its reaction line of thrust, when misaligned with one of the spacecraft's primary axes; causes a control torque to develop about said axis which aids the plume torque about said axis resulting from the plume of the one thruster impinging on a surface such as that of a solar panel on the spacecraft.

Abstract: A means to set spark timing in accordance with engine speed includes a counter to count clock pulses between engine speed reference pulses. A read-only memory has successive memory locations storing an addend quantity and a repeats number. An adder unit, including an accumulator, operates to access the memory locations, and to add the addend quantities to the contents of the accumulator repeatedly a number of times equal to the respective repeats numbers. A comparator produces an ignition firing pulse when the contents of the accumulator corresponds with the reference period number provided by the counter. Improved memory addressing means facilitates altering the spark advance in accordance with a sensed condition such as manifold vacuum, and conserves memory space.

Abstract: A stylus cleaner arm is pushed back to a retracted position when a record-bearing caddy is inserted into the player to load an enclosed record therein. The cleaner arm is held in the retracted position by a record retaining spine upon subsequent jacket withdrawal. The cleaner arm follows the caddy as it is withdrawn from the player after record playback. The cleaner arm engages a switch which actuates a stylus lowering device to lower a pickup stylus onto a cleaning pad disposed on the cleaner arm. The cleaning pad wipes the stylus as the cleaner arm swings back. A timing device deenergizes the stylus lowering device after a preselected time interval to lift the stylus away from the cleaning pad.

Abstract: A pseudo random number generator for generating a succession of numbers manifesting solely three values at random from two-bits.

Abstract: A system for detecting the successful detection of a known serial data sequence of L bits. The system comprises clock pulse generating means for generating a train of clock pulses at a rate f.sub.c, shift register means having N stages each with an output terminal for serially receiving said data sequence at said clock pulse rate fc and for supplying the contents of each stage to the output terminal thereof, and memory means having at least M output terminals, N+M input terminals, and X memory locations each accessable by a predetermined address supplied to said input N+M terminals to supply the contents of said memory location to said M output terminals. Further provided is a latch having at least M input and output terminals and responsive to the signals on the M output terminals of said memory means to supply such signals back to the M input terminals of said memory means a time interval .DELTA. after the entering of a bit of said serial data sequence into said shift register means, where .DELTA.<1/f.

Abstract: The walls of a video disc caddy are vibrated at or near their resonant frequency to dislodge foreign matter adhering to the inside surfaces of the walls. The separated foreign matter is collected by the pressurized air circulating inside the caddy enclosure, and removed therefrom by means of a vacuum.

Abstract: Assembly of a video disc signal recovery stylus apparatus is facilitated by utilizing a stylus holder having a vertical cylindrical end. A conductive leaf spring is inserted in the cylinder followed by a conductive torroidal elastomer. The stylus is then inserted in a hole in the elastomer, all of the parts being held in place by the compressive forces exerted by the elastomer. The second end of the leaf spring is secured to a terminal element which is releasably secured to the stylus arm to provide mobility of the foregoing subassembly during manufacturing. When the subassembly is inserted into a cartridge the terminal element is detached from the stylus arm and inserted into a conformal cavity in the cartridge affording accurate positioning and orientation of the leaf spring.

Abstract: A retainer for holding the stylus arm of a video disc signal pickup cartridge is described which is low cost and occupies little space in the cartridge. The retainer is formed from flat spring stock and shaped to have a three-sided body with fingers extending from the parallel sides to encompass and hold the stylus arm. The retainer is inserted through a top wall of the cartridge and spring tabs which are formed in the sides of the retainer body engage opposite surfaces of the top wall to secure the retainer thereto.

Abstract: An improved automatic gain control (AGC) for a television transmission system comprising a transmitter for transmitting a TV signal via a transmission path to a receiver and having a certain bandwidth in which said transmitter includes a generator for generating a baseband TV signal which can be pre-emphasized, and a variable gain amplifier responsive to the baseband TV signal to produce an amplified baseband video signal. The AGC system comprises a band eliminating filter responsive to the baseband output signal to produce a control signal whose amplitude reflects the change in energy content of that portion of the TV output signal lying outside the allowed transmission bandwidth. The variable gain amplifier is responsive to the control signal to vary its gain substantially inversely as the out-of-band energy content varies. At the receiver a detector detects a component of the received TV signal which has known characteristics, usually constant, in the absence of the gain introduced at the transmitter.

Abstract: A gimballed air puck is used in a video disc mastering system for controlling the depth to which an electromechanical stylus cuts into a metal substrate surface. Air is directed through the air puck toward the substrate surface to maintain the cutting stylus at a given cutting depth. The air puck is gimballed or swivelled to permit the cutting stylus to follow the undulating surface of the substrate during the mastering operation.

Abstract: A video disc signal pickup cartridge is described wherein the stylus arm is coupled to the cartridge body by a highly compliant relatively long, flat member suspended vertically from the top wall of the cartridge. The stylus arm is coupled to the member by passing one end of the arm through a tight fitting hole in the distal end of the member. The member is necked down near the hole to increase torsional compliance with respect to axial rotation of the stylus arm. The proximate end of the member has an expanded compliant region which is compressed for passage through a mounting hole in the cartridge body and allowed to re-expand to compressively retain the member in the hole.

Abstract: A non-contacting RF shielding means is provided to inhibit the flow of energy in a given frequency band through an interface area between two conductive surfaces. A series of stub-like members are provided which are open circuited at one end and connected to a common conductive member on the other end. A portion of the first conductive surface is spaced from the stubs such that a plurality of microstrip lines are formed. The open circuits at the one end of the stubs reflect back as low impedance paths between the first surface and the other end of each of the stubs. The common conductive member is coupled to the second conductive surface. The arrangement thus provides a plurality of low impedance paths between the first and second conductive surfaces in the given frequency band without direct physical contact between the two conductive surfaces.

Abstract: A signal which changes from amplitude X to amplitude Z is applied to a resistor of value R which is series connected with an electrical L-C (inductor-capacitor) delay line unterminated at the opposite end and having a characteristic resistance of value R and one-way delay time T. An output terminal is coupled to the junction of the resistor and delay line. For a time duration 2 T after the input signal changes value, a signal of value (X+Z).div.2 appears at the output terminal and thereafter a signal of value Z appears.

Abstract: The format of two audio input signals, which may be of either matrixed form wherein each signal comprises two common components or of unmatrixed form wherein each signal comprises a respective independent component, is determined by applying the signals to a first network circuit which linearly combines the signals to produce a resultant audio output signal exhibiting a null condition when the input signals are of matrixed form and a non-null condition when the input signals are of unmatrixed form. A null detector responsive to the resultant signal supplies a control signal to a second decoder matrix which decodes the matrixed signals to independent form and couples the decoded signals to respective first and second output terminals when the null condition is detected and which couples the unmatrixed input signals to respective ones of the first and second output terminals when the non-null condition is detected.

Abstract: An M by N switch matrix includes N input switches each single-pole M-throw, M output switches each N-throw single-pole with the N*M outputs of the N input switches coupled directly to respective ones of the N*M inputs of the M output switches whereby a signal applied at any of the N input switches can be coupled to the output of any one of the M output switches. The switches may consist of a plurality of dual-gate field effect transistors enabling the switching matrix to be utilized at microwave frequencies.

Abstract: In a signal expander, the envelope of an input signal to be expanded is detected and applied as a control signal to the gain control input of a variable gain device which expands the input signal. The control signal is applied to the variable gain device via an adaptive filter having improved ripple reduction and transient performance characteristics to minimize audibility of gain changes. The adaptive filter includes a low pass filter for producing a smoothed control signal essentially free of ripple and an analog gate for coupling the greater of the smoothed signal or a further signal to the variable gain device, the further signal being equal to the detector output signal less a constant. Compression of an input signal is provided by applying the input signal to the non-inverting input terminal of an amplifier and coupling the (compressed) output signal of the amplifier to its inverting input terminal via the expander.

Abstract: Impulse noise detection circuitry for determining the occurrence of short noise pulses in TV video signal includes two 1H delay lines to align successive image lines for signal comparison. The amplitude of signal from one image line is compared with the signal amplitude of a succeeding and a preceding image line along a vertical line. If the amplitude of the one signal concurrently exceeds the signal of both the preceding and the succeeding image lines, then a control signal, indicative of the presence of impulse noise, is produced.

Abstract: In a video disc player, an empty sleeve is inserted into an input slot provided in the player along a pair of guide rails to retrieve a record/spine assembly retained therein. The caddy guide rails are provided with a set of oppositely disposed notches near the input slot to block the entry of the sleeve into the player if its entrance angle is too sharp, thereby reducing the possibility of retrieval of the spine without the record.