Abstract: A frequency synthesizer apparatus is disclosed which combines a digital multiplier in the count down and phase comparison section with an oscillator entirely contained on an integrated circuit. Inclusion of the digital multiplier allows simultaneous realization of high loop bandwidth and fast tuning speed. The large loop bandwidth facilitates use of a totally integrated oscillator, which was heretofore not useable because of inferior phase noise characteristics. An integrated filter further enhances loop bandwidth while maintaining stability. Synchronizing the modulus switching of a multi-modulus prescaler with the multiplier coefficient minimizes spurious responses in the synthesized output.

Abstract: Aircraft components utilize flexible fluted extruded twin wall plastic sheet to form aileron hinges, horizontal staibilizers and elevators, vertical stabilizers and rudders, compound landing gear, struts, and control systems which are lighter in weight and lower in cost than previously available structures. The landing gear has damping characteristics superior to previous gear. The invention is particularly well suited to remotely controlled flying model aircraft.

Abstract: A radio paging network transmits non-paging data, such as facsimile images, to lap top computer receivers by formatting the data into a series of packets and interleaving these packets, on a space available basis, into the paging signal.

Abstract: Aircraft components utilize flexible fluted extruded twin wall plastic sheet to form aileron hinges, horizontal stabilizers and elevators, vertical stabilizers and rudders, compound landing gear, struts, and control systems which are lighter in weight and lower in cost than previously available structures. The landing gear has damping characteristics superior to previous gear. The invention is particularly well suited to remotely controlled flying model aircraft.

Abstract: A radio paging network transmits non-paging data, such as facsimile images, to lap top computer receivers by formatting the data into a series of packets and interleaving these packets, on a space available basis, into the paging signal.

Abstract: A radio receiver for use with a time slot paging system which receives intermittent data includes a direct coupled zero IF receiver circuit with at least one automatic gain control (AGC) amplifier stage. DC offset errors are removed from the AGC amplifier stages by a timed zero adjustment circuit that is switched into the AGC circuit just prior to the receipt of data. The resulting zero IF circuit may be miniaturized in monolithic form making it ideal for use in a wristwatch sized pager.

Abstract: A radio paging network transmits non-paging data, such as facsimile images, to lap top computer receivers by formatting the data into a series of packets and interleaving these packets, on a space available basis, into the paging signal.

Abstract: A paging system using synchronized transmission protocol and remote pagers active during monitor intervals to receive data transmitted during corresponding message intervals is provided with adaptive on-off radio receiver control for reducing monitor interval duration to conserve battery power and for centering message intervals within corresponding monitor intervals to increase message reliability. The adaptive on-off control is a function of a recent history of timing errors and thereby accounts for environmental conditions.

Abstract: A chassis module for removably mounting in an opening in the fuselage of a model airplane is arranged to support an engine, a radio, receiver, a fuel tank, a battery and servomechanisms controlled by the radio receiver to control the engine throttle and movable flight control surfaces on the model airplane. The module may include energy absorbers to provide protection to the chassis module and the components mounted thereto in the event of a crash of the model airplane. A magnetically operated latching reed switch is disclosed for applying and removing on-board battery power to the on-board electrical equipment by the use of a magnet brought near the vicinity of the switch from outside the model airplane.

Abstract: The present invention provides an improved single chip radio receiver which has less external components than do previous similar receivers. With the present invention the integrated circuit which includes the radio receiver also has an on-chip adaptive filter. The radio receiver is designed for use in a radio pager which is only active for a very short time slot during a relative long repeat cycle. Thus the adaptive filter only need remain stable for a short period after its coefficients are adjusted to the desired values. The radio receiver includes an external filter which has the same frequency response as desired from the adaptive filter. Immediately prior to activating the radio receiver, the circuit is activated to adjust the parameters of the adaptive filter so that the adaptive filter matches the external filter. The radio receiver is then activated using both filters in series thereby producing the desired radio reception.

Abstract: Frequency control in a miniature receiver is effected by a synthesizer that is operated briefly to provide a tuning voltage to a voltage controlled local oscillator. A capacitor is shunted across the output of the synthesizer and is charged to the level of the tuning voltage. After the capacitor is charged, the synthesizer is deenergized and the diminishing voltage provided to the oscillator by the discharging capacitor is correspondingly supplemented by an AFC voltage that tracks drift of the received signal in the IF passband. The deenergizing of the synthesizer eliminates synthesizer noise and reduces the receiver's power consumption.

Abstract: A direct conversion FM receiver that includes AC coupling and automatic gain control employs an offset frequency at the first local oscillator. The offset frequency prevents the frequency spectrum occupied by the signal modulation from being affected by AC coupling. The offset frequency is chosen so that it translates the frequency spectrum of the received signal outside the DC notch created in the spectrum by the AC coupling. To conserve battery supplied power, an error amplifier coupled between the output of the receiver and the first local oscillator maintains the offset frequency after it has been established by a frequency synthesizer, which is then turned off.

Abstract: A wide area paging system is disclosed in which paging messages input to the system in one local area can be broadcast to a receiver in any other local area without necessarily broadcasting the message in all areas. A local area clearinghouse in each area stores resident subscriber data including current location and receiver serial number. This data is used to transfer messages over a data network to the correct clearinghouse. The system uses a TDM data protocol. The data is encoded and transmitted at a very high rate (e.g., 19,000 baud) in short packets (256 bits/13 milliseconds) via stereo FM sidebands. Receivers are assigned to receive sequentially numbered time slots matching a portion of their address. The addresses of intended receivers are included in the data packets. Battery-powered receivers are deactivated between packets and reactivated in accordance with the sequential time slot number scheme to receive an incoming packet.

Abstract: A wristwatch FM subcarrier paging receiver architecture is disclosed that overcomes the many inherent problems (such as self-oscillation, image responses, spurious local oscillator radiation and interference from entertainment programming) that are encountered in this demanding application. The disclosed architecture includes a tunable notch filter front end, an image cancelling mixer, an automatic gain control circuit, a phase detector for linear detection, frequency feedback for distortion reduction, a synthesized local oscillator, and a frequency plan which can utilize both high and low side local oscillator injection to optimize performance in anticipated interference environments.

Abstract: A system for providing intelligible video program signals and corresponding video synchronization signals to authorized video displays only comprising transmitting means for transmitting scrambled signals of at least one video program; a receiver for receiving said scrambled video program signals for said at least one video program; and a descrambling unit coupled to said receiver and including an electronic ticket removably coupled to the input of said video receiver for intercepting and descrambling the at least one scrambled video program signal from said receiver and recovering the synchronizing signals, and means coupling the recovered synchronization sweep signals and the unscrambled intelligible video program signals to said video display.

Abstract: A method of descrambling received video program signals with transmitted synchronization signals for use in a video receiver comprising the steps of providing first terminals for receiving the scrambled video signal and second terminals coupled to the video receiver and connecting an electronic ticket containing descrambling circuitry to the first terminals for receiving and descrambling the received video signal and coupling the descrambled video signal from the electronic ticket to the second terminals for transfer to the video receiver.

Abstract: An electronic ticket for descrambling transmitted video program and synchronization signals for use in a video receiver comprising first terminals for receiving the scrambled video signals, a descrambling circuit having its input coupled to the first terminals and producing at least a partially descrambled signal at its output, second terminals for coupling the descrambled signal to the video receiver and enclosing portions of the first and second terminals, and the descrambling circuit in a unitary package whereby the ticket can be used as a plug-in unit.

Abstract: Disclosed is a programmable frequency converting filter having a plurality of selectable operating modes, and having frequency passbands of a unique width for each of the operating modes. The programmable frequency converting filter is comprised of a charge transfer device transversal filter, a non-sampling filter, and a frequency band selector. The transversal filter has an output lead coupled to an input of the non-sampling filter, and has clock leads coupled to the output of the frequency band selector. The frequency band selector has control leads for receiving logic signals which together select operating modes from the plurality of modes. The frequency band selector generates, on the clock leads, clocking signals having a unique frequency for each mode of the plurality.

Abstract: The present invention provides a method and apparatus for scrambling and unscrambling television signals to prevent reception of acceptable signals by an unauthorized television receiver while maintaining the television signal recoverable by an authorized receiver. The present invention can also be used for reducing the necessary carrier signal power of a television transmitter.A transmitter (12) passes a television signal through at least one linear filter (30, 32 and 34) of the type that produces multiple time delayed signals of differing time delays.A receiver (14) receives the multiple time delayed signals from the transmitter and passes them through at least one linear filter (64, 66 and 68) to add the signals together so that one signal representative of the original is reinforced, allowing acceptable reception by an authorized viewer.In one arrangement, the linear filters are SAW devices.