Did You Know...
...that the inventor of the electric motor was a blacksmith named Thomas Davenport? Described as "a brilliantly unsuccessful inventor", Davenport invented the first rotary electric motor. In 1836 he headed out -- on foot -- from his Vermont home to file a patent application at the Patent Office in Washington, D.C. By the time he got there, he had squandered away his money and couldn't afford the $30 filing fee so he turned around and went home. When he later mailed in his application with money he'd raised, the Patent office was destroyed in a fire. He did finally get credit for his invention on Feb. 5, 1837.
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| Number | Title | Issue Date |
| 4772892 | Two-axis gimbal A gimbal arrangement for supporting an antenna element steerable in pitch and yaw is shown to include a generally spherical bearing supporting such element, such bearing having a slot formed therein and aligned with the pitch axis to engage a pin affixed ... | 09/20/1988 |
| 4711650 | Seal-less cryogenic expander A cryogenic refrigerator operating on the Split-Sterling cycle principle is disclosed. The refrigerator has a seal-less expander and achieves efficient operation without the use of external control apparatus. This is accomplished by sizing the expander so... | 12/08/1987 |
| 4709346 | CMOS subtractor A subtractor for an N-bit digital number comprising N cascaded cells, each cell being adapted to effect subtraction by two's complement arithmetic and to provide a carry-out signal in accordance with the level of two bits being processed and a carry-in si... | 11/24/1987 |
| 4707800 | Adder/substractor for variable length numbers An adder/subtractor wherein N/2 two bit adders are connected to allow the addition of numbers having N bits, each one of the two bit adders having associated control circuitry adapted: (a) to cause each two bit adder either to add applied bits directly or... | 11/17/1987 |
| 4704701 | Conditional carry adder for a multibit digital computer A multibit digital adder wherein a proper carry-out signal is generated simultaneously in different parts of such adder.... | 11/03/1987 |
| 4700193 | Cross-polarized antenna A monopulse receiving arrangement is shown to comprise orthogonally polarized and electrically separate monopulse antenna arrays, one such array being made up of juxtaposed slotted waveguides and the other being made up of at least one monopulse array of ... | 10/13/1987 |
| 4698840 | Coin operated telephone A self-contained, pre-pay coin operated telephone wherein when the user removes a handset from a switchhook, a local dial tone is generated, prompting the user to enter a telephone number of a called party. Once the first digit of that telephone number ha... | 10/06/1987 |
| 4692714 | Single resonator push-push oscillator A microwave frequency oscillator utilizing a push-push configuration to provide a low noise highly stable output signal at twice the frequency of a single resonator. The single resonator is connected in the feedback loop of two amplifiers. Additional circ... | 09/08/1987 |
| 4676456 | Strap down roll reference Apparatus and method of determining a roll reference for strap down seeker in a spinning projectile is shown to consist of the steps of: (a) determining the frequency spectrum of signals out of an accelerometer disposed in such missile to be sensitive to ... | 06/30/1987 |
| 4675838 | Conditional-carry adder for multibit digital computer A multibit digital adder is shown wherein a pair of carry generating circuitries is disposed between single adders for each bit in the digital numbers to be added, each one of such carry generating circuitries being responsive to a different carry-in sign... | 06/23/1987 |
| 4652882 | Receiver with wide dynamic range A monopulse receiver, wherein a desired wide dynamic range is achieved for range gated monopulse sum and difference signals, is shown to incorporate: (a) a multiplexer for time-multiplexing such signals; (b) a first and a second receiver channel responsiv... | 03/24/1987 |
| 4646095 | Method of resolving closely spaced targets A method of processing signals received by a four quadrant monopulse antenna to resolve the signals from two sources within the sum beam of such antenna is shown to comprise the steps of: (a) separately quadrature detecting each one of the signals (A, B, ... | 02/24/1987 |
| 4641368 | Radio frequency receiver A radio frequency receiver wherein received signals are directed to a mixer through a pair of signal channels, the bandwidth of one of the pair of signal channels being a selected narrow portion of the bandwidth of the other one of the pair of signal chan... | 02/03/1987 |
| 4633442 | Protective circuitry for a read only memory Protective circuitry for a monolithic ROM is shown to include six monolithic FETS interconnected so that two comprise a resistance-capacitance series circuit responsive to a biasing voltage applied thereto to produce a time-varying voltage and the remaini... | 12/30/1986 |
| 4620192 | Continuous wave radar with ranging capability A frequency modulated continuous wave radar wherein analog signals received from a target are converted to digital form, processed by correlation with differently delayed signals, also in digital form, of a modulation waveform repetitively applied to the ... | 10/28/1986 |
| 4617539 | Reflective phase shifter A digitally controlled reflective type phase shifter wherein radio frequency energy is fed to an input/output port of the phase shifter and then coupled from the phase shifter at the input/output port, the phase shifter providing one of a plurality of pre... | 10/14/1986 |
| 4599704 | Read only memory circuit A non-volatile integrated circuit memory is provided having an array of memory elements selectively programmable to store complimentary binary data, each one of such memory elements being formed in a different region of the integrated circuit and having a... | 07/08/1986 |
| 4402761 | Method of making self-aligned gate MOS device having small channel lengths A semiconductor structure wherein a masking layer is formed to cover a portion of a surface of a semiconductor. A first doped region is formed in a portion of the semiconductor exposed by the masking layer. A chemical etchant is brought into contact with ... | 09/06/1983 |
| 4039974 | Coaxial radio frequency switch having integral filter A coaxial transmission line switch is disclosed, such switch having a rotatable coupling element reactively coupled between an input coaxial transmission line and a selected one of a plurality of output coaxial transmission lines. The rotatable conducting... | 08/02/1977 |
| 4037202 | Microprogram controlled digital processor having addressable flip/flop section A digital processor which is adapted for use in the guidance and stabilization of a guided missile. The digital processor is adapted to store a predetermined macroprogram and to process signals produced by various elements within the missile in accordance... | 07/19/1977 |
| 4035743 | Radio frequency oscillator A radio frequency oscillator having an improved varactor mounting structure and tuning slug mounting arrangement is disclosed. The varactor mounting structure includes a coaxial transmission line, one end of the center conductor thereof being capacitively... | 07/12/1977 |
| 4021739 | Distress signal protection system A radio frequency receiver system adapted to monitor the international radio-telegraph distress frequency is disclosed. The system comprises a first receiver section coupled to a receiving antenna. Such receiver section includes an automatic gain control ... | 05/03/1977 |
| 4015260 | Digital MTI radar A digital MTI radar wherein, after an initial period, differences between the composite video signal of a present range sweep and a prediction of the composite video signal of such range sweep are digitized by an analog-to-digital converter.... | 03/29/1977 |
| 4005417 | Frequency spectrum analyzer A frequency spectrum analyzer adapted for use in a real time signal processing radar system is disclosed. In such system a plurality of sets of radar returns, each one of such sets corresponding to radar returns from objects disposed in each one of a like... | 01/25/1977 |
| 4001733 | Ferrite phase shifter having conductive material plated around ferrite assembly A radio frequency phase shifter suitable for X-band operation is disclosed. Such phase shifter incudes a waveguide structure and a ferrite assembly disposed within such waveguide structure. The ferrite assembly has a conductive material plated on the side... | 01/04/1977 |
| 3987442 | Digital MTI radar system A digital MTI radar system is disclosed which is adapted to reject moving clutter returns and to pass, for detection and display, returns from moving targets. The radar system includes means for producing a series of complex digital words representative o... | 10/19/1976 |
| 3982204 | Laser discharge tube assembly A laser discharge tube assembly is disclosed, such assembly including a pair of blocks, one having an optically flat surface and the other having at least a pair of grooves formed in an optically smooth surface thereof, the surfaces of the pair of blocks ... | 09/21/1976 |
| 3979754 | Radio frequency array antenna employing stacked parallel plate lenses A radio frequency multibeam array antenna is disclosed wherein a beam forming network includes a first set of vertically disposed parallel plate lenses coupled between a matrix of radiating elements and a second set of horizontally disposed parallel plate... | 09/07/1976 |
| 3976894 | Analog divider circuitry An analog divider network is disclosed wherein an operational amplifier includes a feedback impedance coupled between an input terminal and output terminal of such amplifier through a switching network. The input terminal of such amplifier is coupled to t... | 08/24/1976 |
| 3974403 | Digital data transmission system A driver circuit for a digital data transmission system is provided with a transistor current limiting network, the network being bypassed by a capacitor. The network is selectively supplied with a disabling signal via another transistor to disconnect the... | 08/10/1976 |
| 3971125 | Method of making an antenna array using printed circuit techniques Radio frequency array antenna structures and methods for fabricating such structures are disclosed wherein a plurality of radio frequency circuits forming the radiating face of an array antenna and a corporate feed are formed on one or more relatively fle... | 07/27/1976 |
| 3970868 | Phase comparator A phase comparator suitable for integrated circuit fabrication is disclosed wherein each one of a pair of differential amplifiers periodically couples an input signal to the output of the comparator through a degenerative feedback arranged high gain ampli... | 07/20/1976 |
| 3969690 | Radio frequency switch A radio frequency switch adapted for operation with radio frequency signals having frequencies above 1,000 MHz is disclosed wherein a pair of strip conductors is disposed in a dielectric between a pair of ground planes, one of such strip conductors being ... | 07/13/1976 |
| 3964069 | Constant beamwidth antenna An antenna assembly for radio frequency energy is disclosed wherein individual antenna elements making up an array are fed in an improved manner so that the width of a directive beam, or beams, formed by such elements is, or are, maintained substantially ... | 06/15/1976 |
| 3955143 | Single sideband generator of bi-level signals A signal processor suitable for real time processing of a complex signal having a relatively narrow frequency spectrum is disclosed. Such signal processor includes a so-called delay line time compressor adapted to receive digital signals corresponding to ... | 05/04/1976 |
| 3950750 | Radar system having quadrature phase detector compensator Method and apparatus are disclosed for correcting amplitude and phase imbalances between the "in phase" and "quadrature" channels of a digital signal processor by determining a correction coefficient from a test signal periodically introduced into the qua... | 04/13/1976 |
| 3946393 | Transponder for use in a radio frequency communication system A transponder for use in a radio frequency communication system is disclosed wherein a received radio frequency signal is converted into an intermediate frequency signal, the latter signal being distorted by a nonlinear network to produce a composite sign... | 03/23/1976 |
| 3940770 | Cylindrical array antenna with radial line power divider A cylindrical array antenna is disclosed wherein rows of antenna elements disposed about the periphery of the antenna each include a feed network coupled to a monopulse arithmetic unit through a radial line power divider and a hemispherical sector selecto... | 02/24/1976 |
| 3936948 | Method for determining azimuthal direction relative to true north Disclosed herein is a method for determining azimuthal direction relative to true north using gyroscopic apparatus. The input axis of a gyroscope is rotated at a substantially constant rate about the local vertical axis. A series of precessional rates at ... | 02/10/1976 |
| 3938158 | Antenna element for circular or linear polarization An antenna element for use in a phased array antenna is disclosed. Such antenna element is a reciprocal device adapted selectively to radiate radio frequency energy of either circular or linear polarization. Such antenna element includes waveguide means f... | 02/10/1976 |
