Abstract: An inverter-type electronic fluorescent lamp ballast powers a fluorescent lamp with a sinusoidal current that is modified by insertion of a measured amount of properly phased third harmonic current, thereby attaining a lamp current crest factor that is substantially better than the 1.4 crest factor associated with a purely sinusoidally-shaped current.

Abstract: A harmonic frequency selecting circuit is provided that simply and effectively provides a desired harmonic frequency output signal and that eliminates the need for frequency multiplier circuits. The harmonic frequency selecting circuit includes an oscillator circuit for generating a fundamental frequency signal and a plurality of harmonic frequency signals of the fundamental frequency signal. A phase modulator circuit is coupled to the oscillator circuit for selectively variably attenuating the generated fundamental and harmonic frequency signals. A bandpass filter circuit is coupled to the phase modulator circuit for selecting a predetermined harmonic frequency output signal.

Abstract: A microwave surface acoustic wave resonator stabilized oscillator includes an amplifier having an input terminal and an output terminal and a feedback circuit disposed around said amplifier for providing a closed loop about said amplifier having an integral multiple of 2.pi. radians of phase shift and excess small signal gain at a frequency f.sub.o. The SAW resonator is disposed in the feedback means and is selected to operate in a fundamental mode of operation and provides a resonant circuit having a resonant frequency f.sub.o. The feedback circuit around the amplifier causes the loop to oscillate at a frequency at which the phase shift is an integral multiple of 2.pi. radians and which has excess small signal gain. As the circuit starts to oscillate, the overall gain in the loop is compressed and the loop amplifier is forced to operate in a non-linear region.

Abstract: A short distance, battery powered, amplitude modulated, crystal controlled RF transmitter for transmitting encoded security information. In its preferred embodiments, the transmitter comprises a novel fifth overtone crystal oscillator which self-produces a carrier frequency at the third harmonic of the fifth overtone of the crystal's fundamental frequency, which carrier frequency is coupled by a series resonant trap, or a pi network, tuned to the carrier frequency to an amplifier stage where the carrier is amplitude modulated via pulse position encoded binary security data. In an alternative embodiment, the transmitter comprises matched crystal oscillator, tripler and amplifier stages. Also disclosed is an antenna including a battery clip contact.

Abstract: A single transistor dual mode crystal oscillator circuit is described which may excite more than one C-mode frquency in a crystal simultaneously such as the fundamental, used as a clock driver frequency, and a beat frequency between the third harmonic and the third overtone frequency, simultaneously. Each signal is thereafter passed through a separate amplifier means to further enhance those outputs for use.

Abstract: An harmonic multiplier comprising a resonant-tunneling diode responsive to a fundamental frequency source oscillator for generating odd harmonics of said fundamental frequency. The resonant-tunneling diode has a current/voltage characteristics curve exhibiting antisymmetry about a zero-volt, zero-current origin and negative differential resistance with high current peaks and low current valleys.

Abstract: A push-push broadband dielectric resonator oscillator circuit that operates in the K and Ka band frequency range has two oscillator circuits that oscillate at the same fundamental frequency. An antiphaseal relationship is maintained between the two oscillators through the use of a dielectric resonator and the desired frequency is obtained by vectorially combining the output signals of the two oscillators that have the antiphase relationship to obtain an output frequency that is twice the fundamental frequency of operation of each of the individual dielectric resonator oscillator circuits.

Abstract: A dielectric resonator oscillator utilizing transmission-type injection-locking for frequency stabilization is disclosed as including a transistor, two microstrip lines, and a dielectric resonator. One microstrip line is coupled to the transistor, while the other microstrip line receives the broadband signal. The dielectric resonator is positioned adjacent to and between the first and second microstrip lines and is operable for coupling an injection-locking signal into the transistor for locking the oscillation frequency of the oscillator. The two microstrip lines are preferably oriented at right angles so that various sizes of the dielectric resonator can be accommodated.

Abstract: A very high frequency harmonic generator utilizes a type III-V (e.g. GaAs) FET. An input signal is applied to the gate of the FET at a sufficient level to induce non-linear functioning of the FET. This causes an output signal to appear between the source and drain having frequency components of at least the tenth harmonic of the input signal. The device is particularly applicable to the generation of microwave signals.

Abstract: Disclosed is equipment for testing a magnetic recording head; comprising a circuit which generates a test signal simulating what the head under test would generate.

Abstract: A reference signal from a reference signal source is supplied to a frequency transformer and a side band signal generator. The frequency transformer is formed mainly by up-converters and produces a frequency m times as high as the frequency f.sub.s of the reference signal. The side band signal generator outputs signals of base and harmonic frequencies f.sub.s, 2f.sub.s, 3f.sub.s, . . . and nf.sub.s (where n is less than m) and produces less phase noise than does the frequency transformer. The outputs of the frequency transformer and the side band signal generator are frequency mixed by a frequency mixer, and one frequency component in the frequency-mixed output is selected by a variable filter.

Abstract: Odd harmonic generator includes two amplitude limiting amplifiers and a frequency selective signal combining network. Sinusoidal signal at frequency of chrominance subcarrier is applied to inputs of both amplifiers. The first amplifier provides signal comprising fundamental and odd harmonic frequency components. The second amplifier provides signal comprising a fundamental frequency component and odd harmonic frequency components that are comparatively much smaller than the odd harmonic frequency components of the first amplifier's output signal. Signals are combined so that fundamental frequency components offset. Output signal at third harmonic of chrominance subcarrier frequency is used as clock signal for CCD comb filter in a color TV receiver.

Abstract: An electronically tunable solid-state microwave frequency source comprises a transmission-absorption filter incorporated within a magnetic structure. The transmission-absorption filter is employed with a tunable solid-state oscillator and tunable solid-state multiplier to provide a continuously tunable microwave signal source with enhanced spurious signal attenuation over a multiple-octave tuning range. The filter structure comprises a sphere of monocrystalline garnet such as yttrium iron garnet (YIG) and two coupling loops disposed in the field region of an adjustable field DC magnet. The coupling loops are disposed orthogonal to the magnetic field and to each other. In a specific embodiment the first coupling loop is operative to receive at its input the fundamental frequency signal and at its output is grounded, and the second coupling loop is operative to receive a harmonic input signal at its input and to convey a desired output signal at its output.

Abstract: A transistorized microwave oscillator comprising a resonator 2 coupled to a transistor 4, 5 and a feedback capacitor 7' around the transistor which produces a fundamental oscillation frequency and harmonics thereof. The feedback capacitor is located within a cut-off waveguide 21 and couples oscillations into the waveguide which blocks the lower undesired frequencies.

Abstract: A high frequency generator including a frequency generator and a multiplier, the multiplier including a diode, which multiplies the output frequency of the frequency generator, and shuts off or reduces an output by suspending or suppressing the multiplying operation through the control of a bias voltage applied to the diode used in the multiplier. The system for cutting off the output by controlling the multiplier is very effective for simplifying the circuit structure and reliably turning off the output.

Abstract: A predistortion error signal, corresponding to the third harmonic of an input signal, is generated by obtaining the absolute value of the input signal and multiplying it by the input signal of given sign to provide the square of the latter times the sign of the input signal. The squared signal then is multiplied by the absolute value of the input signal again to provide the desired cube of the input signal.

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: A microwave transistor oscillator/doubler comprising a Field-Effect Transistor with Terminals G, D and S in combination with a coupling network connected to the terminals G, D and S and composed of microstrip lines with lengths equal to a quarter wavelength at the second harmonic of a fundamental frequency. The doubler further comprises a bias circuit for supplying appropriate voltages to the FET terminals, and an impedance coupler for coupling from the FET D-S terminals to a waveguide load. The coupling network optimizes feedback at the second harmonic between the D-S and G-S ports of the FET to prevent destructive harmonic feedback interaction with the desired signal while providing optimum conditions for feedback at the fundamental frequency. The bias circuit is connected to the coupling network and includes a second network of transmission line elements of lengths equal to a quarter wavelength at the fundamental in order to prevent dissipation of the fundamental frequency therein.

Abstract: A tunable coupling network for a frequency multiplier stage providing a passband for a desired harmonic of a fundamental frequency and rejection notches for undesired harmonic frequencies. The passband of the network can be tuned by changing the value of at least one circuit element to track the desired harmonic of the fundamental frequency over a range of fundamental frequencies. In so doing, the rejection notches also move so that they maintain fixed ratios with respect to the passband frequency as the passband moves. In one embodiment the network comprises first and second tunable circuits each including a variable reactive element. The first resonant circuit includes a variable capacitor and two fixed inductors. The second resonant circuit includes a variable inductor and two fixed capacitors. The two resonant circuits are coupled by an interstage coupling capacitor.

Abstract: A broadband high frequency signal generator is disclosed having a low and a high frequency swept signal source connected to a YIG tuned frequency multiplier. One end of an output coupling loop for the YIG is connected to ground through a PIN diode, and the low frequency signal source is connected to the junction of the output coupling loop and the PIN diode. When the PIN diode is caused to conduct, signals from the high frequency source are passed through the YIG tuned multiplier to an output in the conventional manner. When the PIN diode is not conducting, signals from the low frequency source are passed to the output through the output coupling loop.

Abstract: An integratable third harmonic signal generator comprises an amplitude limiting amplifier, a linear amplifier, and a signal combining network. A sinusoidal input signal is coupled to the limiter and linear amplifiers. The limiting amplifier generates a square wave signal containing a first harmonic (fundamental) component at the frequency of the input signal, and higher order odd harmonics including a desired third harmonic frequency. The signal gain of the linear amplifier is set so that the magnitude of the output signal from the linear amplifier is sufficient to cancel with the first harmonic of the square wave output signal from the limiter amplifier, when these output signals are combined in the combining network. A resulting signal developed at the output of the combining network contains the desired third harmonic component, as well as higher order harmonics at acceptably reduced levels relative to the third harmonic component, to the substantial exclusion of the first harmonic component.

Abstract: A programmable frequency and signalling format encoder/decoder circuit is disclosed which can be used alone or with other like encoder/decoder circuits and external timing and memory circuits to create a tone frequency transmission and reception system having particular frequency and signal format requirements. The encoder provides a sine wave output signal of a selected frequency by constructing the sine wave shape from a predetermined number of sine wave weighted discrete signal segments for each output signal cycle. The width of the segments within a given output signal cycle is determined by programming the encoder with data representative of the selected frequency. To ensure accurate conformance of the frequency of the output signal with a selected frequency, the encoder further includes circuitry for varying the width of individual segments within a single output signal cycle in accordance with the selected frequency.

Abstract: A frequency synthesizer is controlled by the frequency of an input signal. The input signal is sampled and, either during or at the end of the input signal, the output signal is locked on the frequency of the input signal. Octavely related harmonics are combined to provide tone color.

Abstract: Frequency multiplier includes common-emitter input amplifying stage receiving fundamental frequency input signals at input transistor base. Output amplifying stage has output transistor with its base linked to input transistor collector, and with its collector coupled to narrow band load circuit tuned to a selected harmonic frequency. Emitter circuit of output transistor includes parallel resonant circuit tuned to input signal fundamental frequency. Non-linear negative feedback path between output transistor emitter and input transistor base includes capacitor in series with paralleled, oppositely poled diodes.

Abstract: An oscillator is disclosed having a one-stage amplifier and a quartz crystal resonator which operates in series resonance with a L-C oscillating circuit. An oscillating circuit which is tuned to a harmonic of the oscillator frequency is also provided which is connected via a filter device to an output of the amplifier stage. A switching device is provided which short circuits the oscillating circuit tuned to a harmonic as and when required.

Abstract: An amplifier-oscillator frequency multiplier apparatus utilizing a pair of servo-connected amplifiers which are electronically switchable to provide either a coherent amplifier or a non-coherent oscillator.

Abstract: A linear sensitivity voltage controlled crystal oscillator of the type including a resonator coupled to a negative resistance generator. The resonator comprises a crystal connected in series with a voltage variable capacitance device. The response of the resonator is linearized by the addition of an inductance across the voltage variable capacitance device. A resistor is shunted across the crystal to prevent oscillation at spurious resonances of the resonator.

Abstract: The encoder in such system generates a sequence of tones in which every other tone is selected from a first group of tones in one band of frequencies, and the remaining tones in the sequence are selected from a second group of tones in another band of frequencies. The tones in the second group are respectively harmonically related to the tones in the first group, such as having frequencies double the respective frequencies of the tones in such second group. The tones are generated by an oscillator in the encoder, every other tone being multiplied by 1/2, for example. Circuitry, coupled to the oscillator and to the multiplier, alternately delivers the divided and undivided tones, to create the afore-mentioned sequence of tones.The oscillator has associated therewith a switchable impedance, predetermined amounts of which are sequentially switched into the oscillator to cause it to produce the sequence of tones.

Abstract: An RF test signal generator including a driving oscillator, a pulse generr for generating narrow spikes at the oscillator frequency (such as a step recovery diode), a modulator and an attenuator. Since the very narrow pulse exhibits nearly constant amplitude in the frequency domain, a constant amplitude comb spectrum with frequency spacing at the oscillator frequency is generated so as to facilitate automated testing techniques.

Abstract: A circuit for synchronizing a microwave oscillator with a reference source of known frequency. The synchronizing circuit includes a phase-lock loop which compares the output of a free-running, crystal-controlled, voltage-controlled oscillator with the output of a burst oscillator. The output of the burst oscillator has a comb spectrum comprising harmonics of the reference frequency and the phase-lock loop locks onto a selected one of the comb harmonics.

Abstract: An electronically controllable tuning device includes a voltage controlled oscillator adapted to have an oscillation frequency controlled by a control voltage and simultaneously generate a fundamental wave of a predetermined frequency, a programmable frequency divider for dividing the fundamental wave frequency at a frequency division ratio corresponding to the control of a channel selection means and a phase locked loop adapted to compare the fundamental wave phase with the phase of the output of the programmable divider to generate a comparison output and feeding the comparison output back to the voltage controlled oscillator to control the output frequency of the voltage controlled oscillator. The tuning device further includes means for supplying as a local oscillation signal to an intermediate frequency generating mixer one of higher harmonic wave components of the fundamental wave.

Abstract: An integratable third harmonic signal generator includes a signal multiplier coupled to a source of alternating input signal, for providing a first output signal proportional to the input signal raised to the third power. The first output signal includes a first harmonic component and a third harmonic component each proportional to the input signal. Means are also included for deriving, from the input signal, a second output signal in predetermined magnitude and polarity relation with the first harmonic component. The first and second output signals are combined to cancel the first harmonic component and thereby provide a third output signal proportional to the third harmonic component of the input signal substantially devoid of any first harmonic component.

Abstract: A circuit for electronically generating chime-like tones wherein an oscillator circuit output is passed through a diode bridge having another diode across the D.C. terminals thereof and poled to be conductive. The resultant tone is distorted to considerably increase its harmonic content. Further to obtain the desired decoy characteristics a capacitor is included in series with said other diode to thus decrease the current through said bridge as the capacitor becomes charged.

Abstract: A low noise frequency source utilizes a varactor diode to form a parametric crystal oscillator which may be frequency multiplied to the desired microwave frequency, for radar applications.

Abstract: A high-frequency modulator circuit including a frequency multiplier comprised of a first differential amplifier for receiving a base oscillating signal and for multiplying the frequency of the base oscillating signal to thereby produce a higher frequency carrier signal; and a modulating circuit connected to the first differential amplifier for modulating the carrier signal with input information. The first differential amplifier includes a pair of output terminals; and the modulating circuit is comprised of a second and third differential amplifier, each having a pair of input terminals connected to the respective output terminals of the first differential amplifier such that the higher frequency carrier signal is applied differentially to each of the second and third differential amplifiers.