Abstract: In a video receiver, a photodiode is terminated with one or more junction diodes to provide an output voltage that is a log function of the incident optical power. The termination with the diode provides a nonlinear resistance which converts the output current of the photodiode to a voltage, with the output voltage being the log of the input current due to the nonlinear resistance characteristic associated with junction diodes. The subject system eliminates the necessity of providing a transimpedance amplifier used to obtain a voltage from the photo current of a photodetector and also the requirements for a log amplifier to provide the log of the voltage to give the receiver a wide dynamic range. In one embodiment a PIN diode is provided with a series of termination diodes, with the larger of the number of diodes, the more voltage that is available. The series-connected termination diodes provide a passive low noise system for converting the photo current to a log voltage.

Abstract: In a video receiver, a photodiode is terminated with one or more junction diodes to provide an output voltage that is a log function of the incident optical power. The termination with the diode provides a nonlinear resistance which converts the output current of the photodiode to a voltage, with the output voltage being the log of the input current due to the nonlinear resistance characteristic associated with junction diodes. The subject system eliminates the necessity of providing a transimpedance amplifier used to obtain a voltage from the photo current of a photodetector and also the requirements for a log amplifier to provide the log of the voltage to give the receiver a wide dynamic range. In one embodiment a PIN diode is provided with a series of termination diodes, with the larger of the number of diodes, the more voltage that is available. The series-connected termination diodes provide a passive low noise system for converting the photo current to a log voltage.

Abstract: A switching circuit useful in a binary demand feedback DC converter having multiple DC outputs which are all independently regulated using a binary on/off technique is disclosed. A comparator associated with each output compares the voltage at a given output with a reference voltage for the respective given output and generates a first signal the moment the output voltage exceeds the reference voltage. Responding immediately to the first signal a switch opens the converter transformer secondary winding associated with that output from a rectifier and filter. The voltage at that output is determined by the voltage across a capacitor in the filter and the capacitor commences discharging to be below the reference voltage at which time the first signal ceases and the switch reconnects the secondary winding to the rectifier and filter to recommence charging the filter capacitor.

Abstract: In a video receiver, a photodiode is terminated with one or more junction diodes to provide an output voltage that is a log function of the incident optical power. The termination with the diode provides a nonlinear resistance which converts the output current of the photodiode to a voltage, with the output voltage being the log of the input current due to the nonlinear resistance characteristic associated with junction diodes. The subject system eliminates the necessity of providing a transimpedance amplifier used to obtain a voltage from the photo current of a photodetector and also the requirement for a log amplifier to provide the log of the voltage to give the receiver a wide dynamic range. In one embodiment a PIN diode is provided with a series of termination diodes, with the larger of the number of diodes, the more voltage that is available. The series-connected termination diodes provide a passive low noise system for converting the photo current to a log voltage.

Abstract: A switching circuit useful in a binary demand feedback DC converter having multiple DC outputs which are all independently regulated using a binary on/off technique is disclosed. A comparator associated with each output compares the voltage at a given output with a reference voltage for the respective given output and generates a first signal the moment the output voltage exceeds the reference voltage. Responding immediately to the first signal a switch opens the converter transformer secondary winding associated with that output from a rectifier and filter. The voltage at that output is determined by the voltage across a capacitor in the filter and the capacitor commences discharging to be below the reference voltage at which time the first signal ceases and the switch reconnects the secondary winding to the rectifier and filter to recommence charging the filter capacitor.

Abstract: A binary demand feedback DC converter having multiple DC outputs which are all independently regulated using a binary on/off technique is disclosed. A comparator associated with each output compares the voltage at a given output with a reference voltage for the respective given output and generates a first signal the moment the output voltage exceeds the reference voltage. Responding immediately to the first signal a switch opens the converter transformer secondary winding associated with that output from a rectifier and filter. The voltage at that output is determined by the voltage across a capacitor in the filter and the capacitor commences discharging to be below the reference voltage at which time the first signal ceases and the switch reconnects the secondary winding to the rectifier and filter to recommence charging the filter capacitor.

Abstract: The effects of impulse noise on the operation of a microprocessor-controlled Loran-C receiver are reduced by muting or attenuating the received signals in the front end of the receiver ahead of the receiver gain during a time period which preceeds the start time of the pulses being tracked. The attenuation is selectively removed after the start time of each pulse being tracked to permit the receiver to perform its time difference of pulse arrival measurements in the normal manner. The attenuation is also selectively removed during those time periods in which the receiver performs its envelope slope, skywave/groundwave and other such samplings. The attenuation is provided by a muting circuit which is controlled by a time gate signal that derives from the microprocessor of the receiver.

Abstract: A method for processing navigation signals received by a LORAN-C receiver to lessen the effects of noise on the navigation data provided to the receiver user. Time of signal arrival information measured by the receiver is modified depending on the signal-to-noise environment to remove extreme time of signal arrival deviations that are obviously erroneous. The modified information is then averaged to more accurately determine the true time of signal arrival and thereby provide more stable and accurate navigation data.

Abstract: Noise generated in the front end of a LORAN-C receiver that causes noise bias interfering with carrier cycle detection is effectively removed by periodically shifting the phase of all received signals of 180.degree. in the front end of the receiver and then removing any phase shift elsewhere in the receiver where noise is no longer a problem but before the phase shift can affect time difference of signal arrival measurements normally made in LORAN-C receivers. In this manner, noise generated in the front end of the receiver is averaged out and doesn't introduce bias levels to the received signal.

Abstract: LORAN-C navigation apparatus is disclosed wherein digital circuitry and a microprocessor is used to automatically identify LORAN transmitting stations and makes standard hyberbolic navigation measurements. The equipment operator manually enters the group repetition rate into the apparatus for a LORAN-C chain covering the area within which the navigation apparatus is being operated. Initially, the apparatus searches all incoming signals until signals from a master station are received regularly at the stored group repetition rate. The apparatus then closely determines the time of arrival of signals from the secondary stations of the selected LORAN-C chain before changing to a fine search mode in which the exact time of arrival of the secondary station signals is determined; the phase code of the received signals is checked to determine if the received signal is a ground or sky wave, and a determination is made if there is a defective secondary station blink code.

Abstract: A Loran-C navigation receiver is disclosed wherein digital circuitry and a microprocessor is used to automatically identify Loran transmitting stations and makes standard hyberbolic navigation measurements. The receiver operator manually enters a group repetition rate into the apparatus being operated. Initially, the receiver receives and analyzes all received signals until signals from a master and secondary station are received regularly at the stored group repetition rate. The apparatus then changes to a fine search mode in which the exact time of receipt of the master and secondary station signals is determined; the phase code of the received signals is checked to determine if the received signal is a ground or sky wave, and a determination is made if there is a deflective secondary station blink code.

Abstract: A method for self calibration of a LORAN-C navigation receiver utilizing a microprocessor is disclosed wherein the time difference of signal arrival of master station pulse trains from a LORAN-C chain selected by group repetition interval (GRI) information input to the receiver becomes a frequency standard to which the output of an oscillator and counter internal to the receiver is compared to determine frequency error. The error is interpolated over each GRI and a correction factor is added or subtracted to each count output of the counter used to make time difference of signal arrival measurements.

Abstract: A Loran-C receiver cycle detector is disclosed which processes Loran-C signal pulses on a cycle-by-cycle basis of the carrier frequency and generates an output for a specific carrier cycle. Due to received noise, sampling techniques are used to create a histogram which is analyzed to provide feedback used to accurately locate a tracking point on each Loran-C pulse.

Abstract: LORAN-C navigation equipment is disclosed wherein digital circuitry is used to automatically distinguish a master LORAN-C transmitting station from a secondary station. The equipment operator manually enters approximate time difference of signal arrival information for a particular secondary station into the equipment after consulting a LORAN-C chart. The operator then manually determines the exact time difference of arrival using thumbwheel switches and a LED lamp display. This procedure is repeated to determine exact time difference of arrival information for the master and each selected secondary station, and the information is plotted in a well-known manner on the LORAN-C chart to locate the position of the craft upon which the equipment is located. Manual acquisition of secondary stations simplifies the equipment and eliminates interference problems caused by skywaves and other transmissions.

Abstract: LORAN-C navigation equipment is disclosed wherein digital circuitry is used to automatically distinguish a master LORAN-C transmitting station from a secondary station. The equipment operator manually enters approximate time difference of signal arrival information for a particular secondary station into the equipment after consulting a LORAN-C chart. The operator then manually determines the exact time difference of arrival using thumbwheel switches and a LED lamp display. This procedure is repeated to determine exact time difference of arrival information for the master and each selected secondary station, and the information is plotted in a well-known manner on the LORAN-C chart to locate the position of the craft upon which the equipment is located. Manual acqisition of secondary stations simplifies the equipment and eliminates interference problems caused by skywaves and other transmissions.

Abstract: A hand held pager is disclosed which displays a transmitted message in hard copy form on a tape to permit a written record of the message for readout at the convenience of the recipient of the message. The hard copy pager is provided with a printing system in which the printing medium is continually moved past the printing head without significant degradation of the information recorded so that indexing of either the head or the printing medium is avoided.

Abstract: A hand held pager is disclosed which displays a transmitted message in hard copy form on a tape to permit a written record of the message for readout at the convenience of the recipient of the message. The hard copy pager is provided with a printing system in which the printing medium is continually moved past the printing head without significant degradation of the information recorded so that indexing of either the head or the printing medium is avoided. In one embodiment, the pager package includes a cover which is slipped over the main body of the package for providing part of the tape threading channel, with at least a portion of the sliding cover being transparent so that characters imprinted on the tape are readily visible through the cover. Also in this embodiment, a unique address and group call decoder includes a number of normally-off timer decoding elements which are actuated upon receipt of a decoded tone and are cross-inhibited to provide improved shock protection.

Abstract: A method for self calibration of a LORAN-C navigation receiver utilizing a microprocessor is disclosed wherein the time difference of signal arrival of master station pulse trains from a LORAN-C chain selected by group repetition interval (GRI) information input to the receiver becomes a frequency standard to which the output of an oscillator and counter internal to the receiver is compared to determine frequency error. The error is interpolated over each GRI and .[.a correction factor is added or subtracted to each count output of.]. .Iadd.time counts from .Iaddend.the counter used to make time difference of signal arrival measurements .Iadd.are modified in accordance with the determined frequency error to achieve accurate time difference of signal arrival measurements.Iaddend..

Abstract: LORAN-C navigation apparatus is disclosed wherein digital circuitry and a microprocessor .[.is.]. .Iadd.are .Iaddend.used to automatically identify LORAN transmitting stations and .[.makes.]. .Iadd.make .Iaddend.standard hyberbolic navigation measurements. The equipment operator manually enters the group repetition rate into the apparatus for a LORAN-C chain covering the area within which the navigation apparatus is being operated. Initially, the apparatus searches all incoming signals .Iadd.as they are received .Iaddend.until signals from a master station are received regularly at the stored group repetition rate.