Abstract: The range of a target is determined by imaging an illuminated spot on the target onto a detector surface by a focusing lens. The detector is positioned away from the focal point of the image of the illuminated spot, so that the image appears as a blurred circle. The range of the target is uniquely determined by the diameter of the blurred circle. In one embodiment the detector surface comprises a relatively large area having a narrow central area within two parallel boundaries equally spaced from a line representing the locus of the centers of the images on the detector surface. The diameter of the blurred circle can be determined by comparing the light energy received in the narrow central area of the detector with the total light energy received by the detector.

Abstract: A temperature-controlled thermoelectric cooling system regulates the flow of electric current into the thermoelectric cooler in order to maintain a desired cold-side temperature without directly measuring the temperature of the device affixed to the cold side of the cooler. The system includes an apparatus for periodically interrupting the current flowing to the cooler, and during these interruptions measuring the open circuit voltage across the cooler induced by the temperature difference between the hot and cold sides. Computational means use this voltage measurement in conjunction with the temperature of the hot side of the cooler to determine the cold side temperature. From the cold side temperature determination, a controller regulates the current flow to the cooler to maintain a desired cold side temperature.

Abstract: An apparatus for selectively switching between either of two RF clock signal sources utilizes field effect transistors (FET's) as the switching elements. The FET's are driven at their respective base electrodes by complementary signals from open collector logic gates to provide signal source selection. In the event of loss of power to the RF switch, the energy from the RF signal passing through the previously selected switch path provides a positive (enabling) bias to the FET's in that path and a negative (disabling) bias to the FET's in the other path, thereby maintaining the selected path. The open collector logic gate circuits appear as open circuits when power is lost. During normal powered-on operation, the selection logic overrides the RF signal energy biasing circuits.

Abstract: A multiple track playback headwheel is disclosed for use in a helical scan optical tape recording system. The headwheel includes optical diffraction gratings at the center of rotation of the headwheel positioned normal to the rotational axis. A collimated light beam supplied from a laser external to the headwheel, directed along the rotational axis of the headwheel, is split into a plurality of beams by the gratings. The plurality of beams are imaged at the entrance pupil of the playback objective lens which focuses the beams to diffraction limited spots on the surface of an optical tape having information recorded thereon. The illuminated spots are reflected back through the objective lens and are formed into beams which are directed to an information and tracking detecting apparatus and to a focus detecting apparatus.

Abstract: A solar panel satellite subsystem includes a first and second set of solar panels and booms joined together end to end in series and to opposite sides of the spacecraft by spring bias hinges. These hinges include viscous fluid dampers. Each damper has its own heater and thermostat coupled thereto to maintain essentially the same damper temperature as the ground test temperature at each hinge and maintain essentially the same desired rate of deployment at each hinge.

Abstract: An improved companded transmission system uses a transmitter having a first compressor for compressing a signal m(t) of bandwidth B.sub.1 to form a signal C[m(t)]. The transmission system has a bandwidth B.sub.2 where B.sub.1 .ltoreq.B.sub.2. A receiver having an expander to expand the received signal r(t) is provided to produce a signal m.sub.E (t). The improvement consists of a circuit for recovering the frequency components f.sub.L lost during transmission of C[m(t)] and includes a second compressor for compressing m.sub.E (t) in the same manner as m(t) was compressed to produce a signal C[m.sub.E (t)] which contains frequency components f.sub.c lying above B.sub.2. A filter which is responsive to C[m.sub.E (t)] generates (C[m.sub.E (t)]-f.sub.c), and, a subtractor subtracts (C[m.sub.E (t)]-f.sub.c) from C[m.sub.E (t)]. An adder adds f.sub.c to r(t), and, an expander expands the summed signal f.sub.c +r(t) to produce a signal m.sub.1 (t) which is a first order corrected approximation of m(t).

Abstract: In an optical disc player having multiple read/write stations, the shock and vibration which is induced by the operation of loading one disc cartridge onto the turntable of one station may disrupt the recording/playing process in another station. The present invention discloses an apparatus and method for cushioning the shock of the loading process. As the cartridge is being loaded, pressurized air is supplied through orifices in the turntable reference plate to reduce the shock throughout the system. The air between the moving cartridge and the reference plate acts as a spring and damper to reduce the shock of the load cycle. In one embodiment, the pressurized air is supplied through the same orifices which are subsequently used to draw a vacuum which retains the cartridge against the reference plate.

Abstract: In a signal transmission system comprising a transmitter, a transmission medium, and a receiver which collectively form a transmission path, an improvement for processing the signal to enable the transmission thereof over a narrower bandwidth and comprising first logic for decreasing and increasing, respectively, the rate of change of amplitude (dA/dt) of first and second portions of the signal, respectively, whose dA/dt's exceed or are less than a predetermined dA/dt, by amounts which increase at a non-linear rate as the dA/dt of the first and second portions increase or decrease, respectively, to produce a processed signal whose maximum and minimum dA/dt's define a bandwidth narrower than that of the unprocessed signal. Second logic is provided for altering the dA/dt of the processing signal at the receiver in a manner which is the reciprocal of the changes in dA/dt which occurred at the transmitter to reproduce the unprocessed signal.

Abstract: In a satellite power distribution system such as for use in a communications satellite, a first load powering power distribution bus receives power from a first solar panel. A second load powering power distribution bus receives power from a second solar panel. One of the buses is connected to a battery system to provide power to loads during night periods. The loads connected to the other bus are not powered during the night periods.

Abstract: A data transfer system for transferring words of data in either direction between a main memory and N processors includes N registers, each of N words (or multiples of N words) capacity. Each register is connected to its associated processor to transmit data words serially at a given rate therebetween and connected to the memory to transmit N words (or multiples of N words) in parallel therebetween in succession at a rate which allows the uninterrupted serial word transfer at rate X.

Abstract: A closed-loop magnetic roll/yaw control system for high inclination satellites where the predominant component of the geomagnetic field lies in the orbit plane of the satellite. The system includes a torquing means that forms a magnetic dipole moment parallel to the pitch axis. The torquing means is energized to minimize roll or yaw error only in two spaced portions 1 and 3 of its orbit. Each of the portions lie between the extension of the earth's magnetic equatorial plane and a second plane normal to the orbit and passing through the magnetic poles of the earth. Portions 1 and 3 are those parts of the orbit in which the satellite is traveling toward the second plane. The torquing means is de-energized after the satellite crosses the second plane and is in either of the remaining spaced portions 2 and 4 of its orbit.

Abstract: A device comprising a microstrip including a narrow conductor connected in series between a circuit input terminal and the power amplifier, a film of ferrimagnetic material positioned adjacent the conductor and magnetic biasing means. The biasing means normally biases the ferrimagnetic material to operate at frequencies about a selected center frequency for nonlinearly enhancing RF input signals as a function of input amplitude. The device normally, undesirably provides nonlinear phase shifts to the input signal as a function of input power at frequencies removed from the center frequency. By choice of the amount of the bias, for a particular input signal frequency, the device can be adjusted to produce phase shift which changes as a function of input power to offset the nonlinear phase shift of the RF amplifier.

Abstract: A frequency memory module responsive to an input relatively short duration RF burst signal of center frequency f for producing an output signal at center frequency f for a relatively long duration includes a narrow band filter tuned to pass frequency f which is receptive of the input signal, an amplifier connected to the output of the filter and feedback means connected from the output of the amplifier to the input of the filter. Because of the feedback the frequency memory module sustains oscillations at frequency f long after the input pulse is removed from the filter.

Abstract: A clamp circuit in which, so long as the input voltage ranges between preselected voltages +E and -E, the output voltage tracks the input voltage. When the input voltage goes beyond +E or -E, the output voltage is clamped to +E or -E. When, thereafter, the input voltage is changed in the opposite sense by X volts, where .vertline.X.vertline..ltoreq. 2E below its maximum value the output voltage changes by X volts.The clamping circuit utilizes a differential amplifier and circuits providing two feedback paths between the output and inverting input of the amplifier, one or the other being operable dependent on the value of input signal to provide the clamping action described above.

Abstract: A system for reading out the contents of multiple counters onto a common bus comprising a plurality of synchronous binary counters arranged in a ring with each counter having N corresponding stages each having an output terminal on which appears the contents of the stage, an input terminal, and a clock pulse input terminal, with each stage responsive to a clock pulse supplied to its clock input terminal to transfer the signal logic level on its input terminal to its output terminal and with the output terminals of the stages of a given counter comprising the common bus. Also provided is a clock pulse source for supplying clock pulses to all of the clock input terminals and a switching signal source for generating a switching pulse. A switch associated with each stage is responsive to the switching pulse to connect the output terminal of each stage to the input terminal of the corresponding stage of the next adjacent counter in the ring of counters.

Abstract: A system for detecting phase lock loss between first and second two level signals S.sub.N and S.sub.R, and comprising an Exclusive OR (XOR) gate having first and second input terminals and an output terminal, logic for supplying S.sub.N and S.sub.R to the first and second inputs of the XOR gate so that the center points of the respective upper and lower levels are aligned and with the time intervals between adjacent leading and trailing edges of S.sub.N and S.sub.R being nominally equal to .DELTA.t. Also provided is an AND gate having first and second input terminals and an output terminal, and delay logic for supplying the output signal of the XOR gate to the two input terminals of the AND gate with such output signal arriving at one of the input terminals of the AND gate a time interval .DELTA.t after the arrival of the output signal at the other input terminal of the AND gate and a detector for detecting an output signal from the AND gate to indicate loss of phase lock.

Abstract: A one port-to-M port passive signal power divider circuit (or combiner circuit) where M>2 and .noteq. 2.sup.N, M and N are integers, includes M - 1 two-way in-phase passive power dividers having a signal delay D through each path in one or more delay devices having delay D. Each output of each two-way power divider is coupled to an input of another power divider, a delay line or an output port, the arrangement being such that the delay through all ports of the power divider are equal. In accordance with a further embodiment of the invention the outputs of a passive power divider are connected to two-way switches using active components. The switches under control of a control circuit are utilized to switch the input signal to the power divider to any one of 2.multidot.M output terminals of the switches.

Abstract: An improvement in a frequency synthesizer comprising a voltage-controlled oscillator (VCO) for generating an output signal S.sub.VCO of frequency F.sub.VCO, a divider for dividing F.sub.VCO in division cycles with each division cycle consisting of the division of F.sub.VCO by N, Y times, and by (N+M), Z times, in an iterative manner to produce a divided output signal S.sub.N of frequency F.sub.N, where the division ratio is ##EQU1## and where N, Y, M and Z are integers, a reference signal generator for generating a reference signal S.sub.R of frequency F.sub.R, and a phase detector responsive to S.sub.N and S.sub.R to produce an output signal whose amplitude is representative of the phase therebetween. The improvement is a control circuit comprising logic for detecting and averaging the output signal from the phase detector during each division of F.sub.VCO in each division cycle to produce a d.c.

Abstract: A predistortion circuit for a radio frequency power amplifier which has gain and phase shift characteristics that are non-linear as a function of power level of an RF input signal. The circuit includes a dual gate FET, with a drain coupled to the power amplifier. A modulated RF input signal is applied to an inductive matching network which is coupled to the signal gate of the FET. A modulating envelope detected version of the input signal is applied to a video amplifier which is coupled to the FET control gate. The signal applied to the control gate varies the gain of the FET as a function of input signal to compensate for the non-linear gain characteristic of the power amplifier and in conjunction with the matching network causes a phase change of the signal through the predistortion circuit to compensate for the non-linear phase characteristic of the power amplifier.

Abstract: An improvement in a digital frequency synthesizer comprising a voltage-controlled oscillator (VCO) for producing a signal S.sub.VCO having a frequency f.sub.VCO, a first signal generator for generating a plurality of signals S.sub.AS having a spectrum of frequencies f.sub.AS, all exceeding a given minimum frequency f.sub.M, a mixer responsive to S.sub.VCO and to S.sub.AS to produce an output signal having a frequency (f.sub.VCO .+-.f.sub.AS), a divide-by-N divider responsive to (f.sub.VCO .+-.f.sub.AS) to produce a signal S.sub.N having a frequency f.sub.N, a second signal generator for generating a first reference signal S.sub.R1 having a frequency f.sub.R1, a phase detector responsive to S.sub.N and S.sub.R1 to produce a d.c. control signal E.sub.c whose amplitude varies with the phase relation of S.sub.N and S.sub.R1, and a filter for supplying E.sub.c back to said VCO, the VCO being responsive to E.sub.c to produce an output signal S.sub.VCO of frequency f.sub.VCO where (f.sub.VCO .+-.f.sub.AS )=Nf.sub.