Abstract: A transmission line circuit includes a line driver having first and second outputs coupled through a differential transmission line to first and second inputs of a line receiver. A first bias is provided between the first and second inputs of the line receiver. The second bias is applied between the first and second outputs of the line driver. As a result, the first and second biases substantially offset, and preferably cancel, each other. If the differential transmission line is not coupled to a line driver, the second bias associated with that line driver is not applied permitting the first bias to provide a relatively high noise margin.

Abstract: An orthomode coupler (10) for directing both satellite uplink and downlink signals. The coupler (10) includes a waveguide structure (14) having a first cylindrical section (28), a conical section (30) and a second cylindrical section (34) providing a waveguide chamber (22) therein. The conical section (30) provides impedance matching of the downlink signal between the waveguide structure (14) and a plurality of symmetrically disposed downlink waveguides (38-44). The waveguides (38-44) are positioned around the waveguide structure (14) and are in signal communication with the waveguide chamber (22) through openings in the tapered section (30). Irises (46-52) are provided at the connection between the downlink waveguides (38-44) and the waveguide chamber (22) for impedance matching purposes.

Abstract: A dynamic biasing of a transmitter chip is disclosed. The transmitter chip comprises a variable gain amplifying stage, a biasing stage, a phase shifting stage, and a mixing stage. In response to a voltage control signal and a voltage intermediate frequency signal, the variable gain amplifying stage provides a current drive signal and a DC current control signal. While an ampere level of the DC component of the current drive signal and an ampere level of the DC current control signal vary as a function of any variations in the voltage control signal as well as any variation in the temperature, process performance, and supply power of the transmitter chip, a ratio of the ampere level of a DC component of the current drive signal to the ampere level of the DC current control signal is constant. The current drive signal and the DC current control signal establish the dynamic biasing block in a current mode of operation that maintains a constant gain of the mixing stage.

Abstract: An apparatus for providing automatic gain control for use in a satellite terminal of a satellite communication system capable of transmitting a plurality of different modes of data. The apparatus includes a demodulator circuit having an analog to digital converter; a first variable attenuator having an attenuation value set on the basis of a measured power level of a predetermined data signal; and a second variable attenuator having an attenuation value set on the basis of the mode of data being received by the satellite terminal, where each of the data modes have a corresponding predetermined attenuation value associated therewith which is utilized as the attenuation value of the second variable attenuator when the satellite terminal receives the data mode.

Abstract: In a method of calibrating a quadrature transmitter, a first calibration signal is injected into an in-phase transmit branch of the quadrature transmitter, and a second calibration signal is injected into a quadrature transmit branch of the quadrature transmitter. The first and second calibration signals are injected before performing up-conversion in the transmitter and are produced by first and second digital signals. A detector detects an up-converted signal. The detected up-converted signal is digitized. The in-phase and quadrature transmit branches are calibrated by alternately determining the first and second calibration signals while at least varying respective most significant bits of the first and second digital signals, upon said varying the at least most significant bits keeping calibration bit values that correspond to minimum values of the digitized detected up-converted signal.

Abstract: A method of controlling the envelope of a radio signal to be transmitted from a station for mobile radio communications, said radio signal being output by a field effect power amplifier. The method of the invention comprises the following steps: tapping a control voltage applied to the power amplifier; comparing the tapped control voltage with a predefined reference voltage; and causing said control voltage applied to the power amplifier to vary as a function of the result of the comparison.

Abstract: A tunable resonant system includes an electric element, and a core having a controllable parameter that determines the resonant frequency of the system. In order to tune the resonant system to a desired frequency, a low power, narrowband signal is applied at a selected frequency to the electric element. The reflected or transmitted power is measured and the value of the controllable parameter adjusted to vary the resonant frequency of the system in a closed loop until the reflected power is at a minimum.

Abstract: A transmitter is provided for simultaneously transmitting a plurality of signals in a plurality of directive beams to corresponding destination stations, each destination station located in a separate fan within a service area. The transmitter includes a plurality of beamformers, each beamformer receiving one of the signals to be transmitted to an associated fan, each of the beamformers having a plurality of outputs for each different signal to be transmitted. A plurality of Butler matrices each receive one of the plurality of outputs from the plurality of beamformers for each different signal to be transmitted, each Butler matrix having a plurality of outputs in phased relationship to one another, wherein each of the signals to be transmitted is simultaneously provided across the outputs of each Butler matrix in a phased relationship.

Abstract: Noise generating section 106 generates noise data of a white Gaussian noise, and noise adding section 107 adds received data and the noise data. Channel estimating section 108 performs channel estimation using the added data output from noise adding section 107. At this point, when a level of a preceding signal is equal to or less than that of the noise data, channel estimating section 108 is not capable of detecting the preceding signal. Accordingly, in the case where a received level of a preceding signal is extremely lower than that of a delayed signal and a noise level is further lower than the received level of the preceding signal, it is possible to perform pre-equalization using the delayed signal as a desired signal, whereby it is possible to maintain the reception characteristic of a communication partner.

Abstract: The invention relates to a tuning method used in a base station which comprises, in addition to at least one transceiver unit generating signals, a filtering means which is separate from the transceiver unit and filters signals which are generated on the transmitting end of the transceiver unit, of which signals part advances to the filtering means and part is reflected back, and which filtering means is tuned to operate in a predetermined frequency band. The transceiver unit comprises a test signal generating means which generates a control signal and a test signal that is located in a predetermined frequency band, which test signal is transmitted further to the filtering means, a means which generates signals of the same magnitude as the signal which advances to the filtering means and is reflected from the filtering means, which signals are connected from the transmitting end to the receiving end of the transceiver.

Abstract: The invention relates to a transmitter and a method of generating a transmission signal. A first modulation device 12 generates an uncompensated transmission signal Y(t) by modulating at least one baseband signal I, Q with a respective oscillation signal LOQ, LOI. It is an object of the invention to improve a transmitter with such a modulation device so as to reduce the expenditure for the filtering at a later stage that is necessary to attenuate undesirable components in the uncompensated transmission signal Y(t). This object is achieved according to the invention in that a compensation signal C(t) is formed on the output of a second modulation device (14), said compensation signal representing essentially the components to be compensated in the uncompensated transmission signal Y(t). The compensation signal is generated in the second modulation device by modulation of the baseband signals I, Q with suitable auxiliary oscillation signals.

Abstract: A signal having a substantially uniform spectral distribution, e.g., a flat noise signal such as a signal ground, is provided at the input of a bandpass filter such as an IF filter of a receiver circuit, to thereby produce an output signal at the output of the bandpass filter. The output signal is processed in a limiter to produce a limited signal. An average frequency of the limited signal is determined, and the bandpass filter is adjusted based on the determined average frequency. According to one embodiment of the present invention, the bandpass filter comprises a Gm-C filter having a transconductance, and the filter is adjusted by adjusting the transconductance of the Gm-C filter based on the determined average frequency. According to another aspect of the present invention, a desired center frequency for the bandpass filter is identified. A resolution and a desired confidence interval are also identified.

Abstract: In one form of the invention, a resonant cavity filter (50) is disclosed, comprising an input port (210) for receiving an input signal, a dielectric resonator (204) in a cavity, the dielectric resonator operable to receive an input signal from the input port and further operable to produce an output signal at a resonant frequency of the cavity, an output port (212) operable to receive the output signal and a tuning plate (308) disposed in the cavity, the tuning plate coupled to a control means operable to cause movement of the tuning plate, thereby changing dimensions of the cavity, the control means operable to determine a frequency of the input signal, retrieve an expected tuning plate position from a memory (514) based on the frequency, and move the tuning plate to the expected position. Other systems, devices and methods are disclosed.

Abstract: The present invention discloses a method for quickly and easily adjusting the gain of an antenna system. According to an exemplary embodiment of the present invention, the output power of the base station's antenna system is adjusted during the base station's installation process. In the adjustment procedure, the output power of the base station is set to a predetermined value. When a switch is closed, the output power of the base station's associated active antenna system is measured and compared to a stored reference value. If the comparison indicates that the measured output power is above or below the stored reference value, the attenuation of the antenna system is automatically changed in order to properly adjust the gain of the antenna system. The present invention facilitates base station installation by providing a fast and easy gain adjustment method which requires no intervention from the base station or telephone network.

Abstract: A device and method that automatically tune a valve controller coupled to a process control loop generate a plurality of sets of tuning parameters for use by the controller, deliver a test signal, such as a blocked sinusoidal signal, to the controller to force the process control loop through a test cycle while each of the plurality of sets of tuning parameters are being used by the controller and measure a response of the process control loop during each of the test cycles. The device and method then calculate a performance index for each of the plurality of sets of tuning parameters based on the measured responses and select one of the sets of tuning parameters based on the calculated performance indices. The selected set of tuning parameters is then loaded into the controller for use during normal operation of the process control loop.

Abstract: An impedance stabilizing unit including an input port; an output port connected to the input unit; an inductance matching circuit connected to ground and at least one of the input port and the output port, the value of the impedance of the inductance matching circuit being adjusted in accordance with a change of the impedance on the side of said output port. The above unit can be made small, realizing a lowered insertion loss.

Abstract: A transmitter system having an adjustable monolithic frequency stabilization and tuning internal capacitor circuit. The transmitter system has a transmitter for generating and transmitting a transmitter oscillator frequency signal. A data generating chip is coupled to the transmitter. The data generating chip is used for adjusting and controlling the transmitter oscillator frequency signal. A variable capacitor circuit is located internal to the data generating chip and is coupled to a ground pin and one of a plurality of function pins on the data generating chip. The variable capacitor circuit is used for adjusting and setting the centerpoint of the transmitter oscillator frequency signal.

Abstract: A digitally-controlled frequency synthesizer circuit is provided. The synthesizer circuit has a synthesizer that provides as an output a signal that is based on a reference frequency supplied from a resonator circuit. The reference frequency of the resonator circuit can be tuned by varying the control voltage applied to a voltage variable capacitor that is coupled to the resonator circuit. The voltage variable capacitor is located on the synthesizer. A digital-to-analog converter is also located on the synthesizer. The digital-to-analog converter provides the analog control voltage for the voltage variable capacitor based on digital voltage control data.

Abstract: A high Q bandpass filter (102) is tuned by applying a transient (204) to the filter to cause it to ring. The ringing of the filter produces an output damped oscillatory waveform (206) whose zero crossings (208) are converted to a pulse train (210) and counted in a digital counter (112) to a predetermined number n. The output (214) of the counter is compared to an accurate timing signal (216) which has a time duration equal to the time of n pulses when the filter is accurately tuned. The output of the comparator (118) is applied to an integrator (122) to generate a control signal V.sub.c to tune the filter. The high frequency tuning problem is thus converted to a low frequency, time domain problem which is readily implemented.

Abstract: A device and a method for adjusting a bandpass filter, especially a combiner filter. The method includes deriving an RF sample signal proportional to the power of a modulated RF signal which is one of: passing forward to the bandpass filter, reflected from the input of the bandpass filter and passed through the bandpass filter; down-converting the sample signal by another RF signal; detecting the signal strength of the mixing result; adjusting the center frequency of the passband of the bandpass filter on the basis of the detected signal strength. There is an essential frequency or modulation difference between the signals to be mixed, and so the mixing result is an AC signal of a lower frequency. No accurate adjustment of the phase relation of the signals to be mixed is required. Preferably, the frequency or phase difference between the signals to be mixed is accomplished by utilizing the phase modulation contained in the transmission when one of the signals is unmodulated.

Abstract: In one form of the invention, a resonant cavity filter (50) is disclosed, comprising an input port (210) for receiving an input signal, a dielectric resonator (204) in a cavity, the dielectric resonator operable to receive an input signal from the input port and further operable to produce an output signal at a resonant frequency of the cavity, an output port (212) operable to receive the output signal and a tuning plate (308) disposed in the cavity, the tuning plate coupled to a control means operable to cause movement of the tuning plate, thereby changing dimensions of the cavity, the control means operable to determine a frequency of the input signal, retrieve an expected tuning plate position from a memory (514) based on the frequency, and move the tuning plate to the expected position. Other systems, devices and methods are disclosed.

Abstract: A method of adjusting an electronic function implemented in an article that forms a part of a population of articles to be adjusted, the electronic function presenting dispersion from one article to another. When necessary, the method comprises replacing an initial parameter stored in a dispersion correction stage that is coupled to the electronic function with a correction parameter so that the combined response of said function plus the associated correction stage to a predetermined input stimulus lies in a predetermined range. The initial parameter is a centered parameter corresponding to the mean value of the capability curve of correction parameters for the function, the mean value itself being updated whenever the percentage of the population of articles for which test measurements lie outside the predetermined range becomes greater than a predetermined percentage. A large proportion of the measurements performed thus lie within the predetermined range so there is then no need to adjust the function.

Abstract: Tuning a combiner filter, which includes two separate tuning modes: coarse adjustment applied when the combiner is taken into use by utilizing a measuring branch for forward power and a coarse measuring branch for reflected power; and fine adjustment applied in continuous operation by utilizing the measuring branch for forward power and a fine measuring branch for reflected power. The two-stage adjustment decreases the mutual interference of the filters during tuning. The correct tuning frequency of the combiner filter is obtained as the average point of the reversing points obtained in the adjustment process, the filter being driven to the average position. This so-called positional average tuning has two advantages: the effect of noise present in the power measuring line is reduced, and the tuning error caused by the termination of the dynamics of the A/D converter positioned after the detector at low power levels and good combiner filter settings is diminished.

Abstract: A transmitter of a radio communication apparatus includes a voltage controlled oscillator for converting a voltage signal input to the transmitter into a signal having a frequency according to the voltage of the voltage signal, a mixer for mixing a signal having a fixed frequency with the converted input signal and generating a signal for transmission having a frequency at which communication is substantially carried out, a frequency detector for detecting the frequency at which communication is substantially carried out, and a filter for eliminating useless signals that are included in the signal for transmission and have frequencies different from the frequency at which communication is substantially carried out. Signals having frequencies different from the frequency at which communication is substantially carried out are not radiated into space.

Abstract: A multi-carrier radio transmission apparatus provided with an idling detection means for detecting when all of a plurality of modulators are idling and a selective automatic level control means for selectively driving only specific modulators among a plurality of modulators so as to cause them send out their modulated outputs when receiving an idling detection signal from the idling detection means and for enabling an automatic level control unit to perform an automatic level control operation only when receiving an idling detection signal, whereby it is possible to realize a power detector which can exhibit an effect equivalent to that of a diode with a wide dynamic range even when use is made of a diode with a narrow dynamic range.

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 method and circuit for detecting and reducing the impedance mismatch between the directional coupler and the antenna of an RF communications system exposed to externally generated RF signals. The impedance mismatch is detected by the quadrature multiplication of the signal passing through a directional coupler in the forward and reverse directions with the detection being enhanced by the use of a forward direction signal substantially devoid of externally generated RF signal components.

Abstract: The invention relates to a method for fine tuning the resonant frequency of a filter in a combiner, which is provided for combining signals from several radio channels, to the carrier frequency of an input signal to the filter. The power of the output signal from the filter is measured in a narrow frequency band around the carrier frequency of said input signal. Furthermore, the power of the signal reflected by the filter is measured in a narrow frequency band around the carrier frequency of the input signal. Thereafter a measure of the ratio between the two power measurements is formed. The resonant frequency of the filter is adjusted so as to maximize this measure.

Abstract: A method for tuning an RF bandpass filter, especially a combiner filter (10.sub.1, 10.sub.2. . . 10.sub.n) belonging to a GSM system, in which an RF signal having a certain nominal carrier frequency (f.sub.c) is inputted into the RF bandpass filter and a medium frequency of a pass band of the RF bandpass filter is tuned depending on an RF power propagating through the bandpass filter or on an RF power reflected from an input of the bandpass filter. For an easier tuning of the filter and for a tuning accuracy better than before, (a) a carrier is modulated by a signal causing a first predetermined offset (+.DELTA.f), of the carrier frequency, (b) a medium frequency, at which the power propagating through the filter is at the maximum or the power reflected from the input of the filter is at the minimum, is searched for for the bandpass filter, (c) the first medium frequency obtained at stage (b) is stored, (d) the carrier is modulated by a signal causing a second predetermined offset (-.DELTA.

Abstract: A frequency adjustment method for an RF bandpass filter, especially a combiner filter, wherein the center frequency of the passband of the RF bandpass filter is adjusted in response to the RF power reflected from the input of the bandpass filter or passed through the bandpass filter. A sample signal proportional to the RF power reflected from the input of the bandpass filter or passed through the bandpass filter is mixed with a signal of substantially the transmitting frequency. The mixing result is lowpass-filtered and the bandpass filter is adjusted in response to the lowpass-filtered mixing result.

Abstract: Method and apparatus in mobile telephone system including base stations with a plurality of resonance modules, for separately adjusting each resonance module to its own frequency for receiving and expediting telephone signals at this frequency. In each resonance module, tuning is controlled to its given resonance position in relation to the frequency of the incoming signal, by an electromechanical drive which is connected for obtaining drive voltage by phase comparison. The drive voltage passes solely when two input signals differ in phase. When both signals are in phase, the drive voltage is zero, the drive then being stationary and the resonance module being adjusted in resonance to the input signal.

Abstract: In a microwave power source apparatus for a microwave oscillator for generating a microwave, a DC power source supplies a DC power for generating the microwave to the microwave oscillator. A measuring section of a voltage standing wave detector is mounted on a microwave transmission line connected between the microwave oscillator and a microwave load, and measures either one of an impedance seen looking toward the microwave load at a mounted point thereof and a reflection coefficient thereat by detecting a voltage standing wave of the microwave being generated by the microwave oscillator and propagating on the microwave transmission line.

Abstract: An arrangement in tuning resonance modules includes a cavity and resonance body, which is steered to resonance position by a motor, which is driven by a voltage as long as there is a phase difference between the input signal to the resonance module and the output signal (called the measuring signal) from the module. The input signal is of high frequency, and it is desired now to transpose the signals down to low frequency for preventing interference with the measuring signal. The arrangement therefore includes a high-frequency oscillator controlled by a voltage and having a frequency range within which lies the frequency of the incoming signal. From the oscillator output signal and the input signal there is formed in a mixing means the difference between the signals, and in a second mixing means there is formed the difference between the oscillator output signal and the measuring signal such as to form hereby two low-frequency signals. These are compared in a phase detector with respect to phase position.

Abstract: A method and apparatus for operating a frequency division multiplexing (FDM) transmitter within a common communication channel is disclosed. The carrier frequency for each separate channel is adjusted for minimizing intermodulation interference. The system randomly allocates each separate channel within the available bandwidth to provide an initial set of separate channel allocation and corresponding carrier frequencies. Thereafter carrier to intermodulation ratio (C/IM) on each channel is measured and the worst channel with the lowest carrier to intermodulation ratio (C/IM) is removed. The system then repeatedly inserts a channel in available unoccupied bandwidth to produce the largest minimum carrier to intermodulation ratio (C/IM). The deletion and insertion continues until no improvement in minimum carrier to intermodulation ratio (C/IM) can be achieved for said random allocation of separate channels.

Abstract: An on-chip apparatus and method are provided for automatically tuning a continuous time filter in which a single filter selectively filters an information signal or, when tuning is desired, an unfiltered reference signal. During tuning, a controller determines the amplitudes of the unfiltered and filtered reference signals and their ratio. From the ratio, the controller ascertains a corresponding center or tuned frequency of the filter. If the ascertained frequency does not substantially equal a desired tuned frequency, the controller directs a bias controller to adjust the bias of the filter until the tuned frequency is substantially equal to the desired tuned frequency.

Abstract: An autotuning combiner particularly for use in combining signals for radio telephony transmission. The combiner has a series of filter cavities each with an adjuster for fine-tuning the cavity to an input carrier signal. The combiner cavities are stabilized from positional drift in the absence of a carrier signal by means of a mechanical brake which holds the adjuster or a pilot signal generator which simulates the absent carrier signal.

Abstract: A frequency setting system for a radio transmission apparatus of the type transmitting a signal in the form of bursts and changing transmission frequency burst by burst. A frequency division data signal representative of a frequency division number and a strobe signal representative of frequency setting are fed to a frequency synthesizer. The timings for generating the frequency division data signal and strobe signal are determined with no regard to the locking time of the frequency synthesizer which is dependent on the kind of the synthesizer, frequency, etc.

Abstract: A tuning circuit is provided for increasing the power transfer between first and second electrically coupled utilization circuits while controlling the effective source reflection coefficient thereby increasing the power available to the latter wherein the input signal provided at the output of the first utilization circuit is reflected back reducing the power available at the input of the second utilization circuit. The input signal is applied to the first input of the power combiner while a feedback signal proportional to the power loss between the first and second utilization circuits is applied to the second input of the power combiner. The output of the power combiner is increased by the feedback signal for compensating the power loss of the input signal such that the power available to the second utilization circuit is increased.

Abstract: A communication system includes a filter device for passing only a desired carrier frequency, and a circuit for splitting the passed carrier frequency into a pair of signals. A circuit for feeding back one of the signals to the filter device for causing an oscillation to occur at the desired carrier frequency for direct broadcast purposes.

Abstract: A preferred embodiment of a self-balancing reflectometer is disclosed in conjunction with a system including an RF source, an RF load, and an RF transmission channel that carries RF signals transmitted by the source to the load. The self-balancing reflectometer includes a load current sampler that generates a first sample signal related to load current by a first fixed value of gain and a load voltage sampler that generates a second sample signal related to load voltage by a voltage-responsive second variable value of gain. The first sample signal is subtracted from the second sample signal and the resulting difference signal is applied to the RF port of a double balanced mixer. The RF voltage signal appearing at the load is applied to the LO port of the mixer, which generates an IF signal that varies with both rapid load impedance modulation corresponding to load data and long term basal variations in load impedance unrelated to load data.

Abstract: An electronic circuit utilizing a parallel tuned resonant circuit and time variant frequency multiplying to eliminate undesired response changes of the tuned circuit due to temperature is disclosed. The electronic circuit illustrated permits accurate measuring of the change of inductance in a parallel tuned circuit where such change of inductance is due to an input parameter to be measured. The inductive component being measured may be located in environmental conditions which include a large variation in ambient temperature. While normally such wide temperature variations may substantially interfere with the measurement of the value of the inductance in question, the disclosed invention provides for compensation of such undesired changes so that the actual change of the inductance can be monitored without interference.

Abstract: The operating frequency of a radio transceiver and at least one further variable operating parameter of the radio transceiver are controlled in accordance with pre-stored information. Transmit operating radio frequency information is stored in a memory together with associated optimum modulation deviation level information (e.g., so as to maintain a predetermined modulation level at each operating frequency). Receive operating radio frequency information is similarly stored in the memory along with information indicating whether microprocessor clock oscillator frequency is to be shifted (e.g., so as to avoid spurious interfering harmonics emanating from the clock). When operating in the transmit mode, pre-stored modulation gain level information associated with the selected transmit frequency controls the gain of the modulator circuits to compensate for expected changes in modulator circuit gain with change in transmit radio frequency.

Abstract: A method of automatically tuning a high power system by measuring the gardient of component value against efficiency for each component impedance in turn and, for each component, finding two points of equal and opposite efficiency-to-impedance gradient and setting the impedance of the component to a value half-way between these points.

Abstract: A radio frequency transmitter, amplitude modulated, having a single tuner that tunes the frequency oscillator, the isolating filter and the antenna impedance, all at the same time. The transmitter includes a tunable carrier generator for generating a carrier signal of a desired frequency, and a carrier isolator for filtering the carrier signal so as to ensure a clean, isolated carrier signal. A power amplifier is included for amplifying the signal from the carrier isolator. The power amplifier has a certain output impedance. An antenna is connected for transmitting the amplified signal from the power amplifier. The antenna also has a certain impedance. The transmitter further includes an impedance matching device connected between the antenna and the power amplifier for matching the antenna impedance and the power amplifier impedance. Finally, a single control knob is provided for simultaneously controlling the tunable carrier generator, the carrier isolator and the impedance matching device.

Abstract: An improved miniature hand-held low power transmitter utilizing a surface acoustic wave (SAW) resonator as the control element to establish the carrier frequency of the oscillator. The SAW resonator stabilizes the frequency of the transmitter to within 0.05% of the center frequency of the SAW resonator for the condition of the user's hand enclosing the transmitter. This stability allows the companion receiver to operate at a narrow bandwidth, 0.1% of the center frequency of the SAW resonator, thus reducing the spurious noise received by the receiver. The configuration of the transmitter allows schemes such as pulse position or pulse width modulation to be utilized to encode the transmitted information. The physical size of the SAW resonator allows the transmitter to be mounted within a housing small enough to be enclosed by the user's hand.

Abstract: In a computer system comprising a computer having a keyboard, and a display device connected to the computer, an improved position indicator means comprising a mouse having means responsive to movement thereof over a support surface for generating electrical signals indicating the positioning of the mouse, power source means carried by the mouse, circuit means powered by said power source means for generating and transmitting radio signals corresponding to said electrical signal, and processing means associated with said computer for receiving said radio signal and converting said radio signal into a display on said display device positioned corresponding to the positioning of said mouse.

Abstract: An external motor is coupled to a tuning rod extending into a resonant cavity of a transmitter combiner. A microprocessor tuning control system generates motor control signals that cause the motor to rotate the tuning rod, varying the resonant frequency of the cavity so as to minimize the reflected power from the cavity. Incident and reflected power are detected by diodes in the transmitter cable connecter of the cavity. The standing wave ratio is computed and composed with a threshold value to determine if the cavity needs to be retuned. The microprocessor effectuates reading of digital numbers representing the incident and reflected power and makes a "best effort" attempt to tune the resonant frequency of the cavity to the transmitter frequency, using the motor to rotate the tuning rod.

Abstract: A wide band, transistorized power transmitter for the execution of radio traffic requires a filter arrangement consisting of a large number of sub-filters because of the insufficient linearity of the transmitter end stage between the output of the transmitter end stage and the transmitter output. Depending upon the adjusted transmitter frequency, in order to suppress undesired harmonics, one of the sub-filters is switched into the signal path. The relays normally used to switch on and off the sub-filter are unsuitable for carryout out frequency jump operation. By effecting a suitable sub-division of the sub-filters of the filter arrangement into two and more sub-filter groups, between which it is possible to carry out a rapid and non-abrasive switch-over by way of electronic power switches, it is possible without too high an expense to carry out a frequency jump interval which can be arbitrarily adjusted within the overall frequency range.

Abstract: A processor-controlled drive motor system for tuning a cavity klystron monitors the output (amplitude-vs-frequency) of the klystron and compares that monitored performance output with an intended amplitude-vs-frequency profile. Differences between the two characteristics are employed by the processor to generate a set of tuning cavity control signals through which respective stepping motors for displacing each cavity tuning slug are driven. The processor iteratively adjusts the cavity tuner control signals in accordance with a prescribed kylstron tuning program until the monitored amplitude response is within a prescribed tolerance of a preestablished characteristic stored in memory.

Abstract: A dynamic antenna tuning system particularly adapted for VLF frequency-shift (as opposed to on-off) keyed transmitters, employing saturable magnetic switching amplifiers providing variable tuning inductance between the antenna and transmitter and controlled to effect a gradual and not abrupt switching of the radio frequency during on-off transitions to enable narrow VLF frequency spectrum operation.