Abstract: The filter circuit is a filter circuit having plural passbands including a first filter having a first passband, and a second filter having a second passband, with their inputs and outputs connected mutually so that these filters are connected in parallel. Inductor elements are connected in series to the terminal of the first filter to which the second filter is connected, and capacitor elements are connected in series to the terminal of the second filter to which the first filter is connected.

Abstract: A tool and method for bypassing a signal. The bypass tap tool generally comprises a housing, a pair of conductively interconnected contact assemblies and an insulation assembly. The contact assemblies are positioned in and extending from the housing. The insulator assembly is mounted on the housing and includes two insulator extensions. Each extension is adjacent to a respective contact assembly and is moveable between a non-insulating position and an extended insulating position.To prepare the signal tap for service, the bypass tap tool is interconnected with the signal tap with the contact assemblies entering the plug ports and conductively contacting the contact terminals to provide a bypass route and the extensions are moved from the non-insulating position to the extended insulating position wherein they are adjacent to and insulate the contact terminals.

Abstract: This separating device is provided with a transmitting filter and a receiving filter. Each of the transmitting and receiving filters comprises a variable capacity diode and a resonant element, and compose a band elimination filter. Each of the elimination bands of the transmitting and receiving filters can be adjusted by changing the capacity value of each variable capacity diode. The elimination band of the transmitting filter is adjusted so as to coincide with the receiving frequency of the communication channel currently used. The elimination band of the receiving filter is adjusted so as to coincide with the transmitting frequency of the communication channel currently used.

Abstract: Dual band voltage controlled oscillators (VCOs) incorporate a combiner circuit with a single output operable at two widely separated frequency bands such as 900 MHz and 1.8 GHz, for example. The combiner circuit includes a duplexer used as a combiner on the outputs of the VCOs. The duplexer can be realized in transmission line or inductor configurations. The use of the duplexer improves spurious performance and phase noise by more than 10 dB between the two operating frequency bands and supplies band rejection at the non-operating frequency.

Abstract: An extended band, multiple channel multiplexer 10 well-suited for use with satellite communications systems. The multiplexer utilizes a low attenuation, contiguous diplexer 18 containing contiguous diplexer filters 18a to combine two sections 11a, 11b of the multiplexer respectively containing contiguous channel filters 14a, 14b. The multiplexer comprises low attenuation, contiguous diplexer filters 18a tuned in tandem with channel filters 14a, 14b to provide contiguous multiplexing. This approach takes advantage of the constructive interaction between these filters to realize an equivalent contiguous multiplexer. This enables realization of a wide band contiguous multiplexer, which heretofore was impossible to tune. The contiguous diplexer eliminates spurious modes of the channel and diplexer filters, spurious waveguide modes, and out of band interaction between the two portions of the multiplexer. Therefore, tuning of the multiplexer is possible.

Abstract: An interface module having a receiving section and a sending section, the receiving section being provided with a low pass filter, an isolation transformer and a common mode choke transformer, and the sending section is provided with a low pass filter, an isolation transformer and a common mode choke transformer and they are integrated with each other, wherein the receiving section and the sending section are independently formed on a board of the interface module, and the low pass filter at the receiving section and the low pass filter at the sending section are respectively covered by shield cases.

Abstract: A pair of filter units directs incoming signals from an antenna and outgoing signals to the antenna. One of the filter units blocks the outgoing signals and passes the incoming signals while the other of the filter units blocks the incoming signals and passes the outgoing signals.

Abstract: An impedance matching circuit for a multi-band power amplifier has an input port for receiving RF signals from an amplifier, a first path for communicating RF signals in a first frequency band to a first output port, and at least one second path for communicating RF signals in a second frequency band to a second output port. The first path includes impedance matching circuitry for matching the impedance of the first output port and the input port in the first frequency band, and the second path includes impedance matching circuitry for matching the impedance of the second output port and the input port in the second frequency band. The first path contains circuitry which blocks RF signals in the second frequency band, and the second path contains circuitry which blocks RF signals in the first frequency band. A multiband power amplifier includes a multi-band amplifier coupled with an impedance matching circuit for a multiband power amplifier.

Abstract: A CATV passive signal component is disclosed performing bidirectional power insertion or extraction while providing directional RF signal splitting. The signal splitter presents a low burden to the distribution system and can bidirectionally pass alternating or direct current already impressed on the RF signal, or, provide an insertion or extraction function.

Abstract: A receiver system and method of operation are used to tune a selected channel from an input spectrum. The receiver includes an up-converter which responds to a selection setting for up-converting the input spectrum, including the selected channel and an unwanted spectrum; a first diplexer for dissipating the energy of the unwanted spectrum in a manner to reduce distortion effects on the up-converter; a down-converter for down-converting the up-converted selected channel having associated upper and lower sidebands and an intermediate frequency component; and a second diplexer for dissipating the energy of the upper and lower sidebands of the down-converted selected channel in a manner to improve intermodulation of the down-converter.

Abstract: An antenna switch comprises a first switch device (11) for selectively coupling a common point (e) with a transmit terminal (a) or a receive terminal (c), a second switch device (12) having similar structure to the first switch device (11) for selectively coupling a common point (f) with a first antenna terminal (b) or a second antenna terminal (d), and a filter (13) coupled between the switch devices (11, 12) through capacitors (14, 15). Circuit structure of the first switch device (11) is the same as that of the second switch device (12). Components composing those switch devices are mounted on each layer of a multi-layer substrate with a symmetrical relationship. The number of components is small, and the structure of an antenna switch is simplified. It is used in a portable telephone set for switching transmit/receive operation, and switching antennas.

Abstract: The present invention relates to a high-frequency switching circuit, and provides a high-frequency switching circuit capable of withstanding high output power, achieving highly efficient isolation, and reducing an insertion loss using inexpensive pin diodes. A switching control voltage or ground voltage developed at one power supply is applied to a control terminal. A diode resonant circuit includes a diode that applies a signal to an output terminal through an anode thereof and a signal to an input terminal through a cathode thereof, and has a resonant circuit, which attains a parallel resonance owing to a parasitic capacitance formed when the diode is off in the frequency band of the high-frequency signal, interposed between the anode and cathode of the diode. A first bias circuit separates a switching control current stemming from the switching control voltage applied to the control terminal from the high-frequency signal and supplies the switching control current to the anode of the diode.

Abstract: A mixer circuit is provided which incorporates inductive elements for low voltage applications. The circuit consists of a balanced amplifier and a switch composed of transistor pairs driven by a local oscillator signal for multiplying the signal to produce a circuit output signal having a predetermined intermediate frequency. Inductors are used to provide degenerative feedback in the balanced amplifier portion of the circuit. The inductors generate negligible noise and produce a negligible dc voltage drop. The transistors in the circuit are thereby maintained in saturation regions of operation as desired. In accordance with another aspect of the invention, an inductor or, alternatively, a parallel inductor-capacitor circuit, is used as a constant current source in conjunction with the input transistors in the balanced amplifier portion of the circuit.

Abstract: A multilayered frequency separator comprising a plurality of insulating layers, and having at least two notch circuits. The notch circuit is constituted by pattern electrodes formed on interfaces of each of the insulating layers which construct the multilayer structure, and comprises a capacitor component connected to an inductance component. The multilayered frequency separator is suitably used for branching the frequency bands for dual-band handy phone.

Abstract: A duplexer package comprises two surface acoustic wave filter chips having different band center frequencies and a phase matching circuit for matching the phases of the two SAW filter chips, the filter chips and the phase matching circuit being accommodated in one unit, wherein the phase matching circuit is formed in a layer providing a cavity for the filter chips, the layer defining the cavity being located above a face for mounting the surface acoustic wave filter chips. According to the present invention, the height of the duplexer package can be lowered.

Abstract: A three port diplex filter circuit with common, low, and high terminals having a frequency response up to 1 GHz comprises a Chebychev-like low pass filter connected between the common and low terminals and a Chebychev-like high pass filter connected between the common and high terminals, wherein each filter section further comprises a series resonant circuit connected between the low and high terminals, respectively, and ground. At lower crossover values, inductors are wound on powdered iron toroidal forms to counteract characteristic self resonance.

Abstract: A radio frequency filter has a band-pass type frequency response which is controllable in a manner such that the frequency response may be moved between the transmission frequency (TX') and reception frequency (RX') of associated radio equipment. Thus the radio frequency filter may be used both as a transmission filter and as receiving filter, provided that the transmission and reception take place at different times. The radio frequency filter includes a change-over switch, which connects the radio frequency filter to a transmitter when the pass band of the radio frequency filter is in the transmission frequency, and which connects to the receiver when the pass band of the radio frequency filter is in the reception frequency.

Abstract: A diplexer for use in communication of telephony and high-speed data transmission, including television, comprises two filters, each of which is constructed with plural stages in the form of a ladder network, one of the filters being a high-pass filter and the other of the filters being a low-pass filter. The filter components, inductors and capacitors, are located on one or opposed sides of a dielectric substrate. The filter components are arranged to minimize interference between signals traveling in the low-pass filter and the high-pass filter. In the case of a parallel branch of the ladder network in each of the filters, wherein the parallel branch comprises a resonant circuit of inductor and capacitor, the branches of the respective filters are located at opposite parts of the array of the filter components.

Abstract: A new system for allowing PCS Providers to share cell sites, and more particularly multi-sector antennas, is provided. The present invention utilizes primarily passive, linear components to combine the transmit signals of PCS Providers which reside in non-adjacent frequency bands over a multi-sector antenna and to distribute from a multi-sector antenna the receive signals in all frequency bands of the PCS Providers.

Abstract: A low power, low cost distributed digital loop (DDL) carrier system that combines television and voice telephone signal transmission over coaxial cables. The DDL system employs a passive/active tap module (114) that controls the steering of the video and telephone signals. The high frequency down stream telephone signal is not processed until a routing terminator (110) converts it to lower frequency signal for transmission in the lower frequency subsplit channel. The telephone signal is then transmitted back up through the subsplit where the active circuitry of each tap intercepts the telephone signal, selects the needed signal and transmits it down to a network interface unit (120) located at the subscriber premises.

Abstract: In a digital mobile radio apparatus according to the present invention, a duplexer for connecting a transmitter and a receiver to a common receiving/transmitting antenna is constructed from an isolator and a receiving band-pass filter. The receiving band-pass filter prevents a transmitted wave from entering the receiver. Impedance matching is effected so that the isolator can prevent a received wave from entering the transmitter while suppressing the entrance of signals radiated from other mobile units in the same transmitting frequency band but at a different operating frequency.

Abstract: In an antenna duplexer, one antenna is used by switching transmission signals and reception signals having different frequencies. The antenna duplexer includes a high-frequency switching circuit and a band-pass filter. The high-frequency switching circuit supplies the transmission signals from a transmission part to the antenna. The band-pass filter outputs the reception signals outputted from the antenna to the predetermined receiving circuit. In the band-pass filter, the frequency characteristic is selected and set to impress the frequency of the transmission signals, and simultaneously the reflected wave generated at the input end so that impedance increases at the frequency band of the transmission signals.

Abstract: A modular, multi-channel, contiguous output, multiplexer which combines directional filters with the diplexed output of two multi-channel multiplexers, each covering a contiguous frequency band, i.e., one is a low multiplexer and the other a high multiplexer, and one or more quasi-elliptical directional filters after the diplexer output to cover the hole left by the diplexer crossover. A preferred embodiment may essentially consist of: 1) a 12 channel contiguous multiplexer, either a hybrid directional and manifold type multiplexer or a short circuited multiplexer, covering frequencies, e.g., in the range from 3.7 GHz to 4.2 GHz; 2) a 6 channel contiguous multiplexer spanning frequencies substantially in the range from 3.42 GHz to 3.62 GHz; 3) a diplexer including a 6 section Chebyshev filter, with a passband of frequencies, e.g., in the range of 3.4 to 3.620 GHz, and about 30 dB attenuation at 3.7 GHz, and an 8 section Chebyshev filter passing frequencies, e.g., in the range of 3.7 GHz to 4.

Abstract: A system (10) for combining a plurality of transmission channels within a multiple channel communication system includes a master computer (20) that controls the transmission frequency and schedule of a plurality of channel transmitters (18). Each channel transmitter (18) is electrically connected to a channel transmitter combiner filter (12). Each channel transmitter combiner filter (12) is fixedly tuned to a unique bandwidth window along the electromagnetic spectrum, and two sets (24), (26) of channel transmitter combiner filters are formed of the channel transmitter combiner filters (12) whose unique bandwidth windows are adequately spaced for electrical isolation along the electromagnetic spectrum. Each set (24), (26) of channel transmitter combiner filters is electrically connected to a common antenna (28) by means of a three decibel (3 dB) coupler (22).

Abstract: A high-frequency apparatus usable as a branching filter, branching filter module and/or a radio communication apparatus. The high-frequency apparatus includes a conductor substrate, a first dielectric layer provided on the conductor substrate, a strip conductor provided on the first dielectric layer, and a second dielectric layer provided on the strip conductor and having through holes provided therein. At least one elastic surface-wave element is provided over the second dielectric layer in a position above the strip conductor and is connected to the strip conductor by the through holes.

Abstract: A diplexer constructed on a stripline board includes a plurality of filters each having a series of filter sections providing an elongated physical configuration to the respective filter. Each filter section comprises an inductor and a capacitor. Each of the capacitors for each of the filters is formed in stripline format by laminating a pad of electrically conductive material to a sheet of electrically conductive material with the interposition of a layer of dielectric material between the pad and the sheet. Each inductor is formed as a coil wound about a core of air or solid magnetizable material. To provide for reduced physical size of the circuitry, thereby to accommodate emplacement of the circuitry within a television cable connection box, there is provided in a preferred embodiment of the invention filters of higher and lower frequency channels wherein the filter of the lower frequency channel has larger inductors.

Abstract: A method for using the same input/output pin on an integrated circuit ("IC") for both a high frequency AC signal and a DC signal simultaneously and a first circuit means to accomplish this multiplexing is disclosed. The circuit topology comprises a first and second capacitor, coupled between the AC signal input and the AC signal output. A first and second resistor are coupled to the same input/output pin as the capacitors but between the two capacitors and respectively to a DC signal input and DC signal output. The DC signal path thus lies between the two capacitors and sees them as open circuits, while the AC signal path sees the two resistors as open circuits and the capacitors as short circuits.

Abstract: A local control mechanism for automatically parking an active combiner filter and activating an alternate combiner filter in an auto-tune combiner in a radio telecommunications network is resident entirely at a remote base station. The mechanism samples the radio frequency (RF) energy level on the active combiner filter in an auto-tune combiner and determines whether the measured RF energy level exceeds a predetermined RF energy threshold. The mechanism then determines the number of RF energy samples taken, compares this number to a trigger number, and parks the active combiner filter and switches to an alternate combiner filter when the number of consecutive RF energy samples below the RF energy threshold exceeds the trigger number.

Abstract: Acoustic frequency mixing devices for controlling high frequency signals by the generation of acoustic waves are disclosed. The devices include (a) a crystalline substrate of MTiOXO.sub.4 (wherein M is K, Rb, Tl and/or NH.sub.4 and X is P and/or As) having a surface with at least two input areas; and (b) an input interdigital transducer deposited on each of at least two signal input areas of said substrate surface, each IDT suitable for connection to a source of electric signal and for inverse piezoelectrically generating acoustic waves (e.g., SAWs or B-G waves) in the substrate. For controlling high frequency electrical signals, the substrate surface has a output area and the device typically includes an output electrode (e.g.

Abstract: A device for tuning a combiner filter. The measuring signals (P.sub.rl . . . P.sub.rn, P.sub.F1 . . . P.sub.Fn) of a number of different combiner filters are multiplexed to the same detectors. Multiplexing allows the measuring and adjusting electronics required by the tuning and adjusting means of combiner filters to be simplified considerably especially with a high number of combiner filters. Multiplexing of measuring signals is used primarily to select the sample signals of the forward and reflected power of one and the same combiner filter to be tuned for the measuring electronics. In the invention selectors for reflected power and forward power are independent of each other, which allows isolation measurement between different channels. The sample signal of the forward power of one combiner filter and the sample signal of the reflected power of another combiner filter are thus connected to the measuring electronics.

Abstract: A miniaturized portable telephone is provided in which a receiving radio-frequency filter is formed by a SAW filter, while a transmitting radio-frequency filter is formed by a dielectric filter and they are mounted on a substrate. The transmitting and receiving sides are connected to an antenna by transmission lines, the length of which is set to have a high impedance in the mutual transmitting and receiving frequency.

Abstract: An RF Choke and tap having improved insertion loss, amplitude modulated distortion of video and audio carrier signals at CATV frequencies. The RF choke includes a 20 AWG magnetic wire wound on a ferrite rod. The magnetic field effects of the choke are optimized by selecting the choke winding pattern, rod core material and positioning of a resistor between selected windings. The wire is wound by placing two groups of the 4 tightly wound wires adjacent the ends of the rod. A group of 3 very loosely wound wires is separated from the wound wires and placed between the groups of 4 tightly wound wires. A resistor is electrically connected to a first wire in one of the groups of tightly wound wires and connected to a first wire in the group of the loosely wound wires.

Abstract: When the bandwidth of a duplex filter having a certain band-width, intended for a radio telephone, is increased by affecting the coupling between the resonator circuits, the stop band of the filter is at the same time deteriorated. According to the invention, the stop-band attenuation can be improved by coupling a surface-wave filter, coupled as a notch circuit, in parallel with one of the resonator circuits of the duplex filter.

Abstract: A filter, particularly suitable for radio frequency applications comprises a first filter which, in turn, comprises at least a pair of intercoupled resonators (RES1, RES2), and a SAW filter (SAW) which is coupled between the two intercoupled resonators so that a signal input to the filter at its input (IN) is coupled through the SAW filter to provide an output signal at its output (OUT). This provides a filter with all the advantages of a SAW filter, but with the ability to withstand the high power requirements of radio frequency applications. If three or more resonators are present in the first filter, then an amplifier can also be integrated in the filter. The SAW filter (and the amplifier if present) are inductively or capacitively coupled to the resonators depending upon the type of filter that is required.

Abstract: An arrangement for forming a radio test loop in a radio unit comprising several radio transmitters and radio receivers wherein each radio transmitter comprises a test signal output, which is adjustable during an operation of testing the radio transmitter, from a high-impedance state to a low-impedance state for outputting a test signal derived from a signal transmitted by the radio transmitter to a frequency converter for conversion to the receiving frequency before looping to the respective radio receiver. To reduce cable-laying required for the test loop, the test signal outputs of all the radio transmitters are connected with spacings of approximately n.lambda./2 to a common combiner cable connected to the input of the frequency converter, where .lambda.=the wave length at the transmitting frequency and n=1, 2, 3, . . . .

Abstract: The invention relates to switchable band filter apparatus for switching signals on-board a satellite, enabling signals of different and unforeseeable bandwidths to be switched between multiple input ports and multiple output ports. The invention also provides various payload architectures using such apparatus. Finally, the invention provides methods of implementing such apparatus and architectures for performing transparent switching of signals on-board a satellite.

Abstract: A combination surge and diplex filter is provided for a CATV distribution amplifier. In a first preferred implementation, an integrated surge and high pass filter section is provided when the CATV amplifier is used only in the forward direction. Provision is made for a plug-in low pass filter section which is matched to the high pass filter section. The plug-in low pass section is used to form a diplex filter if the reverse direction capability of the CATV system is required from the distribution amplifier. In a second preferred implementation, the integrated surge and high pass filter section is segmented into a surge filter segment which is designed as a divisible part of the high pass filter section. A plug-in module is then provided with a high pass filter segment having those components of the high pass filter section which were not necessary for surge protection and a low pass filter section matched to the high pass filter section.

Abstract: A method and apparatus is disclosed for providing salphasic distributions of synchronization signals to physically separated entities typically composing a system. Salphasic behavior is a fundamental property of standing waves in any physical situation governed by the wave equation and where the signal is isophasic, i.e., its phase remains constant, over extended regions and abruptly jumps by 180.degree. between adjacent regions. This behavior is used to minimize the phase shifts due to propagation path lengths. A sinusoidal signal is generated and impressed on a distribution medium which is in turn connected to receivers at the various entities to be synchronized. The medium and loads due to the receivers are composed to cause the synchronizing signal to form nearly pure standing waves in the medium. This enables all the entities to receive the synchronizing signal substantially in the same phase to within an ambiguity of exactly 180.degree.

Abstract: The invention discloses a three-port filter being able to connect alternately a receiver and a transmitter to a common antenna in a ratio system operating by the time division principle. The first signal path between the first and the third ports comprises all resonators (R1, R2, R3, R4). The second port is connected to one (e.g. R3) of the resonators in the first signal path, whereby a first subset (R1, R2) of resonators lies between the first and the second ports, and a second subset (R3, R4) of resonators forming the signal path between the second and the third ports lies between the second and the third ports. The resonators of either subset are switchable resonators, whose resonance frequencies can be shifted between two frequencies by an external control (Control). At the first control value of the control (Control) the resonators of this subset pass the RF-signal substantially without attenuation, and at the second control value they strongly attenuate said signal.

Abstract: A branching filter in which an input/output port, a first dielectric filter for use in transmission and a second dielectric filter for use in reception are coupled with each other through a branching filter circuit. The branching filter circuit includes a first line provided between the input/output port and an input port of the second dielectric filter, a second line provided between the input/output port and an output port of the first dielectric filter, and a third line provided between the input/output port and the ground. In the filter, conductor lines for use in connection between ports are used for the first and second lines.

Abstract: A filtering system for separating a composite signal containing two signals in different frequency bands: a high frequency signal and a low frequency signal. The composite signal to be separated is input into an inductive element in a high frequency filter section. The high frequency signal is immediately coupled by mutual induction with a resonant element of the high frequency filter section, the resonant element being designed so that the low frequency signal is not coupled because of the low value of its frequency. The low frequency signal is transmitted to low pass filter section which rejects any signal remaining in the high frequency band.

Abstract: An antenna sharing device having a transmission filter connectable between a branch node of an antenna and a transmitter and a reception filter connectable between the branch node and a receiver. At least one of the transmission filter and the reception filter includes: a first parallel resonance circuit having a capacitor and a coil connected in parallel; a second parallel resonance circuit magnetically coupled to the first parallel resonance circuit; and a capacitor serially connected to the first parallel resonance circuit. One of the first and second parallel resonance circuits has a first resonance frequency, the other of the first and second parallel resonance circuits has one of the first resonance frequency and a second resonance frequency, and a combination of the first and second parallel resonance circuits and the capacitor forms an equivalent circuit providing a small insertion impedance at a third resonance frequency.

Abstract: A device for tapping the line power of a cable television distribution system. The device is intended for connection to a standard port of a cable tap. The device includes a threaded portion for connection to the port, a housing and an output connector mounted to the housing. Disposed within the housing is a module containing electronics forming a low pass filter to remove the line power from the RF television signal. The module is slidably mounted to extend out of the housing and is biased into engagement with the hot side of the port. The mounting of the electronics within a slidable module permits the low pass filter to be in close proximity to the port so as to eliminate interference with the television signal. The slidable housing also permits the device to be used with ports which differ in depth.

Abstract: A branching filter, which is operatively connected between an antenna and a communication device which utilizes different frequency bands, suppresses a mutual interference between signals transmitted to and from the communication device. An antenna circuit, which is operatively connected between the antenna, or a branching filter, and the communication device, converts an impedance with respect to a signal in a frequency band having a lower frequency, and reduces loss resulting from a capacitive antenna impedance.

Abstract: Disclosed is a novel two-way duplexer structure for the simultaneous transmission and reception of circularly polarized microwaves. This two-way duplexer of the type designed to connect a first set of two inputs/outputs to a second opposite set of two inputs/outputs, each input/output of said duplexer being connected to the combination channel of a combiner/divider, the two division channels of each combiner/divider each providing for the connection with one of the division channels of one of the combiners/dividers connected to a distinct input/output of the opposite set of inputs/outputs, through distinct phase-shifting means.

Abstract: A superconducting microwave selective filter system having a superconducting filter connected to receive RF signals and perform filtering before the RF signals are applied to nonlinear circuitry such as receiver protectors and low noise amplifiers. A single pole n throw point switch selects a desired one of the filters to provide a receiver with a desired frequency, such as an active radar frequency. The low loss and high dynamic range of a superconducting filter permits these filters to be employed in the front end of the system before system nonlinear circuitry.

Abstract: A new class of multiplexing filter structure has both the properties of channelized filtering and channelized linear frequency discrimination. The channelized filter-discriminator is intended for use as part of a microwave receiving system possessing a high probability of intercept for incoming signals. The selective properties of the band pass filters provide an interference-reduction capability while the discriminator property provides for instantaneous frequency measurement. The design procedure for achieving a very high degree of discriminator linearity in association with a reasonable selectivity comparable to a maximally flat filter uses theoretical design data provided in a normalized table generated by computer optimization. A hardware realization of a 64 channel multiplexer-discriminator is described and measured data is presented that agrees very closely with the theoretical predictions.

Abstract: Transmission-Reception Separating Filter with a PIN diode. A PIN diode is arranged in the transmission channel of the transmission-reception separating filter that has the transmission channel for forwarding a high-frequency current from a transmitter to an antenna. A rectifier is provided that generates a control current for the PIN diode from the high-frequency current flowing in the transmission channel. As a result, a separate power supply is not required for controlling the PIN diode in the transmission channel.

Abstract: A filter system which may be configured either as a stopband (notch) or passband filter having controlled gain and low ripple throughout its stopband or passband. The system includes a filter network which is operative for splitting an input signal spectrum into a pair of complimentary spectrum components and a coupler for proportionately combining these spectrum components in accordance with a prescribed gain factor. The filter network may either comprise a pair of complimentary band reject and band pass filters connected to a common input terminal or a diplexer including identical filters coupled between a splitter and a combiner.

Abstract: A dual function antenna system and method. A system is provided for using a single antenna for both the reception of low frequency navigational signals, such as LORAN-C, and high frequency communications signals in the VHF region. The antenna is at a remote location from a low frequency receiver and a high frequency transceiver. Both the low frequency and the high frequency signals are coupled to the receiver and transceiver, respectively, over the same transmission line at one end thereof. A preamplifier is provided at the location of the antenna to increase the strength of the low frequency signal applied to the transmission line. A high pass filter is provided to couple the antenna and the transmission line and prevent feedback from the output of the preamplifier from reaching its input. The other end of the transmission line is coupled to the high frequency transceiver by a high pass filter, and to the low frequency receiver by a low pass filter.