Abstract: A circuit is provided which is capable of band switching a voltage controlled oscillator (VCO) while maintaining the relative sensitivity of the voltage controlled device and, hence, the control line voltage itself. The circuit includes an array of capacitors, including a pair of capacitors and a voltage variable capacitor (varactor), a switch, and a tuning coil. When the switch is in the open position, the pair of capacitors are connected in parallel with the varactor. When the switch is closed, the pair of capacitors are connected to ground, arraying themselves on opposite sides of the varactor. In this closed position, the overall capacitance of the tuned circuit increased, thus lowering the tuned frequency of the circuit. Since the switched capacitance (i.e., the capacitance which changes the tuned frequency of the circuit) is arrayed on both sides of the varactor, the varactor maintains its relative sensitivity.

Abstract: The invention relates to an ultra-high frequency oscillator operating in the X band. The oscillator circuit comprises a common gate-connected field effect transistor. The source connected tuning circuit comprises a variable capacitor of the varactor type controlled by a voltage and a choke in parallel. The control voltage is decoupled from earth by a capacitor. According to the invention, the transistor, the varactor and the capacitor are integrated into the same box or case in the form of a micromodule. The capacitor acts as a base for the transistor and the varactor, which are welded in juxtaposed manner. The length of the connection between the varactor and the source of the transistor has a minimum value, which makes it possible to broaden the linear frequency band as a function of the control voltage.

Abstract: A pre-distortion shaping network employing a field effect transistor as one leg of a resistive voltage divider for shaping the modulating signal of a voltage controlled oscillator is described.

Abstract: An oscillation circuit includes as its principal components a Clapp capacitor and two feedback capacitors connected to each other and a resonance coil. A first series circuit including a first variable-capacitance diode and a first DC cutoff capacitor is connected in parallel with the resonance coil, while a second series circuit including a second variable-capacitance diode and a second DC cutoff capacitor is connected to a first diode such that a certain polarity terminal of the second variable-capacitance is faced against the same polarity terminal of the first diode. One end of the second DC cutoff capacitor in the second series circuit is connected to the one of the feedback capacitors. Furthermore, means is provided at the joint of the first variable-capacitance diode and the first DC cutoff capacitor for applying a DC voltage to enable the first and second variable-capacitance diodes.

Abstract: A low power, wide bandwidth oscillator capable of oscillating at frequencies of greater than 350 MHz and capable of being implemented in relatively few parts is disclosed. A switching section controls the resonant frequency of a resonator and is connected in DC series with an amplifier. A regulator-buffer section simultaneously serves as a voltage regulator and RF signal buffer.

Abstract: A low noise oscillator is disclosed wherein the collector and base of a transistor are respectively biased at different voltages from a common voltage source to be conditioned for generating a high frequency oscillation with a resonant circuit connected to the emitter and collector. The high frequency oscillation developed at the base of the transistor is coupled to ground. A capacitive circuit is coupled between the collector and base of the transistor to eliminate the effect of a voltage-dependent capacitance inherently present in the transistor between its collector and base on the frequency of the oscillation in order to reduce the level of noise introduced to sidebands.

Abstract: A frequency synthesizer circuit of the phase-locked loop type for receiving a reference signal and generating in response thereto a plurality of local oscillator (LO) output signals is provided. The synthesizer includes a varactor-controlled oscillator having one or more hyperabrupt varactor tuning diodes for providing an octave bandwidth phase-locked loop output RF, and a plurality of series-connected emitter-coupled logic (ECL) circuits connected to the output of the varactor-controlled oscillator for generating a plurality of local oscillator output signals RF/N, where N=2.sup.x, x=1, 2, 3 . . . . The frequency synthesizer also includes a programmable frequency divider in the feedback loop thereof for reducing the frequency of the phase-locked loop output signal RF by a selectable factor.

Abstract: An oscillator including an active device (38), a surface acoustic wave resonator (40) connected in a feedback relationship to the active device and an impedance matching circuit is disclosed. The impedance matching circuit in one arrangement is an output impedance matching circuit including an inductor (46) connected in the feedback loop to the output of the active device. In another arrangement, the impedance matching network is an input impedance matching network including an inductor (42) connected in the feedback loop to the input of the active device. In another arrangement of the invention, a varactor diode (60) is connected in the feedback loop and is controlled by a reverse voltage which changes the capacitance of the diode, adjusting the frequency of the oscillator.

Abstract: Between insulative layers (31-37, 41-44), a multilayer substrate comprises at least one dielectric layer (26-29). It is possible to form capacitors (58), resistors (46), and wiring conductors (61, 62) in the substrate. The at least one dielectric layer should be of at least one dielectric composition which has a perovskite structure. Preferably, each insulative layer is of an insulating material which consists essentially of aluminum oxide and lead borosilicate glass. The substrate is convenient in manufacturing a crystal oscillator by mounting a crystal vibrator (71) and a transistor (72) on the principal surface(s). Examples of the dielectric composition are:Pb[(Fe.sub.2/3.W.sub.1/3).sub.0.33 (Fe.sub.1/2.Nb.sub.1/2).sub.0.67 ]O.sub.3,Pb[(Mn.sub.1/3.Nb.sub.2/3).sub.0.01 (Mg.sub.1/2.W.sub.1/2).sub.0.30 (Ni.sub.1/3.Nb.sub.2/3).sub.0.49 Ti.sub.0.20 ]O.sub.3,andPb[(Mg.sub.1/2.W.sub.1/2).sub.0.66 Ti.sub.0.34 ]O.sub.3.

Abstract: A planar varactor tuned microstrip oscillator for Ka band operation comprising a GaAs Gunn diode, a varactor diode, an impedance inverter microstrip line placing the varactor in shunt with the Gunn diode, an impedance matching transformer connected from the output of the Gunn diode to a load connection means, a source of negative bias potential for the varactor and a source of positive bias potential for the Gunn diode.

Abstract: An oscillator having the ability to oscillate at a plurality of discrete frequencies in response to an applied digital signal is disclosed. A crystal-controlled, resonant circuit utilizing passive components as frequency determining elements and a PIN diode switching scheme allows the oscillator to demonstrate a tendency for each of the plurality of discrete frequencies to drift equally in response to temperature changes. A two-transistor, emitter coupled amplifying section uses a current mirror for biasing and provides an impedance matching network.

Abstract: In a distributed IMPATT structure, power is coupled out through a side contact. That is, in previously proposed distributed IMPATT structures, the gain medium (the active region of the IMPATT) operates as a transmission line. The prior art has attempted to couple output power from the gain medium through an end contact, i.e., through a contact which is perpendicular to the primary direction of energy propagation (and also to the direction of maximum elongation) of the active medium. In the present invention, a sidewall contact extends in a direction which is parallel to the principal direction of propagation of the energy in the active medium. Thus, the sidewall contact plus the active region together can be considered as a single transmission line. This extended transmission line is also connected to a second distributed semiconductor element which functions as a varactor.

Abstract: An oscillator circuit suitable for use in a local oscillator of a tuner of a television receiver set. A feedback circuit comprised of a feedback capacitor (17) is connected between a junction of a tuning diode (10) and a correcting capacitor (11) connected in series therewith and the emitter of an oscillation transistor (1). Oscillation voltage developing across the correcting capacitor is fedback to the emitter of the oscillation transistor through the feedback capacitor. When the tuning diode is conditioned to have a large capacitance value, a large oscillation voltage is fedback to the transistor through the feedback capacitor whereas when the tuning diode is conditioned to have a small capacitance value, a small oscillation voltage is fedback to the transistor through the feedback capacitor. The oscillator circuit continues to oscillate stably over a wide frequency range whenever the tuning diode changes from the small capacitance value to the large capacitance value or vice versa.

Abstract: A voltage-controlled oscillator includes an amplifier having two emitter-coupled differential amplifier stages, and in whose feedback network, connected in series, are a 3dB-90.degree. coupler and a surface-wave transmission line. Two variable capacitance diodes are connected to the two terminals of the coupler that are not used as input or output terminals, and a frequency control voltage is applied to both diodes. The oscillator is particularly well-suited for the transmission of digital signals with transmission speeds of over 100 Mbit/s.

Abstract: A narrow band, voltage controlled crystal oscillator having a linear frequency versus tuning voltage response. The oscillator uses a composite resonator in a novel circuit configuration with a resulting improvement in oscillator output signal frequency stability.

Abstract: A modulated elongate cavity oscillator with minimized modulation nonlinearities includes a first cavity having dimensions which determine the fundamental resonant frequency of the oscillator, a gain element disposed in said first cavity that provides amplification to sustain oscillation, and a varactor diode disposed in said first cavity for modulating the fundamental frequency. A first waveguide is coupled to the first cavity for absorbing modes higher than the mode of the fundamental frequency which have an electric field maxima concurrent with the longitudinal center line of the first cavity. A second waveguide is coupled to the first cavity for absorbing modes higher than the mode of fundamental frequency which have an electric field minima concurrent with the longitudinal center line of the first cavity, whereby the first and second waveguides provide effective attenuation of higher order modes such that modulation nonlinearities due to the existence of higher order modes are substantially eliminated.

Abstract: The oscillator includes a two-terminal device (1) as an active element and an impedance-matching network (4) for matching the two-terminal device to a load (A). The impedance-matching network is formed by a coupler (4) having four terminals (2, 3, 7, 8) two of which (7, 8) are terminated with impedances (5, 6) whose values are chosen depending on the output power or frequency to be adjusted or are varied as desired. Another of the terminals is connected to the active two-terminal device (1), and the fourth terminal (3) is the oscillator output.

Abstract: In a voltage-controlled oscillator having an LC resonant circuit including a varactor circuit so that resonant frequency is controlled by a D.C. bias or control voltage applied to the varactor circuit, three or more varactors are connected in series in one embodiment so that a high-frequency voltage applied to the varactor circuit is divided into a plurality. The varactors may be connected in the same direction or opposite direction. In another embodiment, a plurality of series circuits of varactors are connected in parallel to provide the varactor circuit, where each series circuit comprises two or more varactors. A series-parallel connection of a plurality of varactors may be arranged in a matrix. In order to reduce undesirable stray capacitance, some or all varactors are attached to a printed circuit board so that they are normal to the plane of the printed circuit board. In one embodiment an auxiliary printed circuit board is employed so that some varactors are spaced from a main circuit board.

Abstract: An LC-type oscillator employing a differential amplifier to switch a tank circuit in response to a feedback signal. A voltage controlled variable capacitor is employed to control the frequency of oscillation. The bias across the variable capacitor is closely controlled to avoid errors in the frequency of oscillation during the period of startup, which would otherwise create an undesired error in the oscillation frequency.

Abstract: A push-pull microwave oscillator circuit, including two transistors, for producing the second harmonic of a fundamental frequency at a symmetry point of the circuit which is connected to the bases of the transistors through identical arrangements of circuit elements. The circuit includes tuning means coupled to at least one of the transistors, an output and an input. The output, which is utilized to provide to a phase comparison means an output signal at the fundamental of the second harmonic frequency, is coupled to the base of at least one of the transistors by a capacitive impedance. The input, which is utilized to receive a tuning signal produced by the phase comparison means in response to the output signal, is coupled to the tuning means.

Abstract: Improved output power performance is obtained in a millimeter-wave integrated-circuit (MIC) voltage-controlled oscillator by forming an output circuit and a bias input circuit in a suspended stripline configuration, which is subject to relatively low losses compared with microstrip designs. A Gunn diode and a varactor diode are mounted in alignment and in close proximity to each other. The suspended microstrip configuration includes a suspended substrate with a Gunn diode output circuit and a bias input circuit on one side, and a varactor diode grounding pad on the other face of the substrate. A sliding short-circuit device aligned with the Gunn diode output circuit provides tuning of the oscillator over a relatively wide range, and avoids having to trim the Gunn diode circuit components for final adjustment of the frequency.

Abstract: A single-crystal oscillator comprising a single transistor and a capacitor divider connected in a feedback path, which includes the crystal input and output ports, between the collector and base of the transistor, thereby to provide a low-impedance input port to the crystal. The impedance of the crystal output port, which is connected to the base of the transistor, is also low. As a result of the low crystal input and output port impedances, the oscillator is capable of operating without any significant levels of spurious crystal frequencies, and can be switched between crystal and voltage-controlled modes of operation without frequency pull or lock-up to the crystal when operating in the voltage-controlled mode.

Abstract: A high-frequency negative resistance circuit for use in a voltage controlled crystal oscillator has a pair of input terminals thereby defining an input current and input voltage. The high-frequency negative resistance circuit includes a sensing circuit for sensing the input current, a biasing voltage source and a load impedance connected to the voltage source. The high-frequency negative resistance circuit further comprises a current mirror circuit connected to the sensing circuit and to the load impedance for producing a current in the load impedance. The current in the load impedance is approximately equal to the input current. The current mirror circuit also controls the sensing circuit to cause the input voltage to decrease as the input current increases. Decreasing input voltage with increasing input current defines the negative resistance. When this negative resistance circuit is configured with a crystal and a voltage controlled capacitance, an oscillator capable of high-frequency operation results.

Abstract: In a compensated VCO circuit arrangement for providing constant modulation level over a wide frequency band a VCO is disclosed having a linear VCO gain factor vs. control voltage curve over the wide frequency band of interest. A compensation network is coupled to the VCO to provide an audio output having a linear output level vs. control voltage curve. By appropriately matching the two linear curves the variation in modulation level over the frequency band of interest is substantially reduced.

Abstract: A resonant-circuit, high-frequency electrical power supply for a mass spectrometer has a transductor for magnetically retuning the power supply in response to tuning variations produced by operating variations in the mass spectrometer.

Abstract: A voltage controlled oscillator for use in a phase locked loop is provided with a first varactor circuit that responds to a control signal to set the center frequency of the oscillator, and with a second varactor circuit comprising a modulation varactor that responds to a modulation signal to cause the oscillator to produce a modulated output. The modulation sensitivity of the oscillator is made relatively constant between upper and lower center frequencies by applying a portion of the modulation signal to the first varactor circuit in addition to the control signal.

Abstract: In a method of fabrication of a module formed by a semiconductor diode which oscillates in millimeter waves and by a variable-capacitance diode, the oscillating diode is mounted on a pedestal at the center of a support base. A ring of fused silica for supporting a metallic disk of predetermined diameter serves to form a radial space between two metallic surfaces with a view to readily obtaining oscillation in a predetermined frequency band. A similar ring is welded at one end to the opposite face of the disk and at the other end to another metallic base fitted with a central variable-capacitance diode. Flexible connections bonded to the diodes are clamped between the rings and the disk. The module may be incorporated in a tunable oscillator.

Abstract: Stray capacitance is reduced in a wideband tunable oscillator network by arranging the resonant circuit as one or more series circuit branches wherein a variable capacitance such as a varactor diode is interposed between two substantially identical inductors. In the disclosed VHF-UHF oscillator, the inductors are realized by TEM transmission lines of the stripline variety. The stripline is formed by a multilayer printed circuit board arrangement and two resonant circuit branches are interconnected in a manner that permits biasing of the varactor diodes without the use of blocking capacitors in the resonant circuit path.

Abstract: A tunable oscillator develops a signal having a frequency variable over a range of frequencies in response to a control signal. A frequency determining resonant circuit includes two voltage-variable capacitance diodes in an arrangement for adjusting at least one endpoint of the frequency range. As a result, the relationship between the magnitude of the control signal and the frequency of the oscillator signal can be adjusted while avoiding mechanically adjustable reactive elements. The disclosed arrangement is suitably employed with resonant circuits other than those in oscillators.

Abstract: A voltage controlled oscillator includes a main varactor diode coupled to a frequency resonating circuit to produce an output frequency in response to a control voltage. A secondary varactor diode of an appreciably lower voltage to frequency sensitivity ratio is coupled to the main varactor diode. A modulation input circuit is coupled to the secondary varactor diode to enable modulation of the resonating output frequency. A linearizing circuit is coupled to the secondary varactor diode and tracks the main varactor diode capacitance to continuously adjust the bias voltage of the secondary varactor diode to provide constant carrier modulation deviation.

Abstract: To extend the variation range of a controlled frequency oscillator comprising a piezoelectric element, a lithium tantalate or lithium niobate element is used in parallel with which there is connected a linearization circuit comprising an inductance in series with a parallel circuit comprising a resistor and a capacitor.

Abstract: A wideband VCO including a coaxial cavity with a negative impedance semiconductor diode and a tuning varactor mounted in a center conductor thereof. A variable bias circuit connected to the tuning varactor for tuning the VCO through a predetermined range. An output probe including a coupling varactor in contact with the center conductor. The variable bias circuit is coupled to the coupling varactor to alter the output coupling capacity as the frequency of the oscillator changes so that the output power remains substantially constant.

Abstract: A monolithic microwave voltage-controlled oscillator including one or more FETS integrated with a wide-ratio varactor. The varactor includes interdigitated anode and cathode patterns laid out on a single thin epitaxial layer. The punch through voltage of the epitaxial layer, and hence the resistivity-thickness product of the epitaxial layer, must be low. Since the substrate is semi-insulating, punch through to the substrate does not become uncontrollable, but simply permits modulation of the capacitance over a very wide range. The FETS are formed in the same epitaxial layer with the varactor, and complicated doping profiles are not required.

Abstract: An integrated circuit for a controllable frequency oscillator using integrated variable-capacitance capacitors.The circuit is a MOS type. Each of the variable capacitance capacitors comprises a n.sup.+ -p junction at the interface of a first region of n.sup.+ conductivity type and a second region of p conductivity type, which are formed in a semiconductor substrate of n type. The first and second regions emerge at the surface of the semiconductor wafer. A decoupling capacitor is associated with the variable-capacitance capacitor by the formation of a stack arrangement comprising the portion of insulating oxide layer covering the surface portion of the wafer at which said first region emerges and an electrically conducting layer covering said insulating layer portion.

Abstract: A microwave voltage-controlled oscillator includes a varactor-controlled tuned circuit connected to the gate of an FET. The gate of the FET forms a Schottky barrier contact with the channel region. This Schottky barrier operates to clip the RF voltages generated in the gate circuit, and this clipping is used to provide the necessary gate bias to set the operating point of the VCO. No other source of bias is provided, and thus no DC return path from the gate circuit to the source or drain of the FET exists. Thus, the other circuit elements normally required to establish the gate operating point, which would have high frequency resonances, are eliminated. This permits operation of a microwave VCO over an extremely broad bandwidth.

Abstract: A phase-locked loop for use in the common T1 systems. The phase relationship of the clock pulse output of a voltage controlled oscillator is determined with respect to an incoming data pulse train. If the clock signal leads the data signal, an error signal of a first polarity is applied to an integrator whose output is provided to the VCO to reduce the frequency of the clock pulse. If the clock signal lags the data signal, an error signal of a second polarity is applied to the integrator whose output is provided to the VCO to increase the frequency of the clock pulse. The logic of the circuitry is such that the output of the integrator is always either increasing or decreasing, even if there is zero phase error between the clock pulse and data pulse (i.e. the loop has infinite gain for zero error). The integrator continues to integrate in a first direction until the frequency of the clock pulses is adjusted so far that the lead is changed to a lag or vice-versa, with respect to the next data pulse.

Abstract: A monolithic voltage controlled oscillator is fabricated on a single semiconductor body. The oscillator includes an FET and a varactor diode interconnected such that a voltage applied across the varactor modulates the oscillating frequency of the FET output.

Abstract: A single Colpitts-type oscillator has a plurality (here, three) of optional inputs, each having a separate oscillating circuit individually associated therewith. By suitably applying a potential to a selected one of the oscillating circuits, the oscillator may be made to produce one of a plurality of predetermined carrier wave frequencies. The inventive circuit configuration eliminates large volume components such as coupling capacitors and enables hybrid IC construction, which miniaturizes the circuit. The circuit is particularly useful in walkie-talkie FM transceivers.

Abstract: A wideband, modulation sensitivity compensated, voltage controlled oscillator which automatically and continuously compensates over a wide bandwidth for modulation sensitivity variations resulting from changes in the center frequency of oscillation. The invention includes a compensation network which continuously varies the coupling between the modulation circuit and the oscillator tank circuit in response to changes in the steering control signal applied to a steering network. Continuous modulation sensitivity compensation is thereby provided over a wide bandwidth.

Abstract: In a microstrip frequency modulated oscillator, the linearity of the modulating circuit incorporating a varactor diode is adjusted by using a microstrip transmission line as a secondary resonator in conjuction with a variable reactor. The varactor is connected to one end of this resonator which end is also connected to the main resonator of the microstrip oscillator. The variable reactor is connected between the other end of the secondary resonator and ground.

Abstract: A microwave evanescent-mode oscillator comprises a length of waveguide W1 having a cut-off frequency higher than the working frequency of the oscillator together with a Gunn element G disposed within the waveguide characterized in that the oscillator comprises, spaced in sequence along the waveguide a Gunn element G post-coupled into the waveguide and spaced from a first end of the waveguide, a capacitive member C and at the other end of the waveguide an end wall formed by a diaphragm D having therein an output aperture I for coupling out energy from the waveguide.

Abstract: A VCO (Voltage Controlled Oscillator) is provided with a full set of tuning voltages from a reduced number of reference voltage sources, such as potentiometers. Logic controlled switch means delivers any of the reference voltages individually or predetermined combinations thereof as the tuning voltages to the VCO. A reference voltage source potentiometer is provided for each of the odd numbered tuning voltages, and a piecewise linear approximation is provided for the intermediate even numbered tuning voltages by generating the average of two adjacent odd voltages.

Abstract: An oscillator arrangement is disclosed which is controllable in its frequency and which comprises a control input for frequency variation and a transformer output, whose frequency-determining oscillating circuit possesses, as a controllable reactive element, two varactor diodes which are connected in opposing fashion and whose capacitance largely represents the oscillating circuit capacitance. Two feedback oscillator circuits are combined to form a push-pull circuit in that the output terminals of the oscillator circuits are connected in respect of d.c. to a reference potential by way of a central tap of the primary winding of a common output transformer. In addition, the two varactor diodes are oppositely poled and interconnected in respect of d.c.

Abstract: An exceptionally wideband, synthesizer controlled voltage controlled oscillator is disclosed which is characterized by a plurality of pin diode frequency shift networks which, when actuated shifts the frequency of the oscillator in selectable binary steps within a wide frequency range in the order of 48 MHz. Special means are included to prevent undesireable parasitic oscillation modes when such frequency shift networks are in an inactuated, switched off mode. A multiple varactor tuning circuit is provided for selecting a precise frequency within a relatively narrow frequency band on the order of 6 MHz.

Abstract: The invention comprises a microwave oscillator using a stripline circuit. The active device utilized in the oscillator is a bipolar transistor. A microstrip circuit is coupled to the emitter of the transistor while the collector is coupled to ground. This generates a negative impedance characteristic at the base of the transistor at the operating frequency. The operating frequency is determined by a varactor which is series tuned with an inductor. The impedance of the series tuned circuit is transformed to match the input impedance of the transistor by a microstrip circuit. Microstrip isolation circuits are utilized to couple appropriate bias signals to the emitter and the base to establish the proper operating point for the bipolar transistor. The output signal is taken from the base circuit of the transistor through the series combination of two microstrip circuits and a capacitor. A second varactor is loosely coupled to the base circuit of the transistor to provide for fine tuning.

Abstract: In an FM modulation circuit, a variable capacitance circuit employs a transistor as a variable capacitance element. The transistor has resistors connected between the emitter and base thereof and between the collector and base thereof, respectively, and is connected under the unbiased state to an oscillating transistor of an oscillation circuit constituting the FM modulation circuit. In correspondence with an input signal applied across the emitter and collector of the variable capacitance transistor, the emitter--collector capacitance of this transistor is varied to vary the oscillation frequency of the oscillation circuit.

Abstract: A tuner for a television receiver includes a voltage controlled local oscillator for tuning VHF channels comprising a transistor arranged in a common base amplifier configuration and a parallel tuned circuit including a varactor diode responsive to a tuning voltage and a first inductor configuration for the low VHF band and a second inductor configuration for the high VHF band connected between the collector and emitter electrodes of the transistor. A second varactor diode also responsive to the tuning voltage is connected between the emitter and base electrodes of the transistor to expand the range of the local oscillator in its high VHF configuration to permit tuning of channels in a midband cable band between the low and high VHF bands without the need for a third inductor configuration.

Abstract: An electronically tunable oscillator comprises a transistor coupled to ground by an emitter resistor. The collector and base of the transistor are interconnected through an inductor which has a tap connected to a bypass capacitor and a B+ voltage source. The source maintains the collector and base at the same DC potential. The collector of the transistor is coupled to a capacitance which cooperates with the inductor to provide a tuned circuit. At least part of the capacitance is provided by a varactor whose value can be controlled to determine oscillator frequency. The magnitude of the oscillator frequency is limited to two times the base to emitter voltage of the transistor and the use of the emitter resistor cooperates to minimize distortion.

Abstract: Disclosed is a feedback regulated oscillator which comprises a reference signal source, a variable local oscillator, a converter responsive to the variable local oscillator for developing a signal, compatible with the signal of the reference source, having a magnitude which is responsive to the frequency of the local oscillator, and a comparator, responsive to the reference signal source and to the converter, for controlling the frequency of the variable local oscillator.

Abstract: A hand held, short range FM radar device is provided employing a unique tracking circuit and a predistortion circuit to linearize the sweep function to a Gunn oscillator which produces the rf signal. A parabolic generator comprising a linear operational amplifier and passive elements connected thereto is used to shape the saw tooth sweep signal to the Gunn oscillator.The output is directly read out on an LED display; an audio signal is also produced whose frequency is a function of target distance.