Abstract: The present inventive concept combines two signals, each representative of a portion of a single signal, wherein the two signals have different non-linear slopes, and produces a single linearly changing output signal indicative of the combination. This circuit is specifically used in combination with the feedback loop of a delayed automatic gain control circuit to detect the signal level applied to the gain control circuit and to provide a linearly changing output signal representative of the decibel value of the signal applied to the automatic gain control circuit. This is accomplished by linearizing the two different signals independently, and establishing a maximum value for one signal, a minimum value for the other signal, and summing these in conjunction with a reference to produce a single composite linearly changing signal.

Abstract: A drop-in module in an RF frequency amplifier circuit is illustrated having space feedback between the gate and drain terminals, and having a unique mounting technique for electrically connecting the source terminals to the ground plane on the opposite side of the substrate portion of the drop-in module. The electrical connection is accomplished by using a U-shaped piece of strap metal, which is inserted in two slots with the legs or tabs of the U-shaped strap metal being bent over to be soldered to the source leads, while the bit portion of the U-shaped member is soldered to the ground plane on the opposite side of the substrate. This allows easy attachment and removal of the FET to the exposed electric circuitry, while still maintaining a definable and appropriate low impedance electrical path from the source leads to the ground plane.

Abstract: Space feedback comprising a shield over the tuning elements of a FET radio frequency amplifier provides positive feedback between the gate and drain terminals to raise the gain of the amplifier above what it would be without the space feedback, while simultaneously lowering the noise figure. Not only is the relative noise lowered, but the absolute amount of noise is lowered.

Abstract: A unitary component operating as a low noise amplifier incorporates several other tuning components in conjunction with an FET. By adjusting the tuning components, the overall amplification and impedance characteristics of the unit can be standardized in spite of typical variations in impedance and amplifying characteristics of the FET by itself. The incorporation of such a drop-in module in a microwave circuit, simplifies testing and repair of the remaining portions of the circuit, since the drop-in modules can easily be tested and adjusted for proper operation in a test jig separate from the actual operating circuit.

Abstract: A variable transformer is illustrated to be used primarily with high frequency transistors and other high frequency amplifying means to provide optimum impedance matching characteristics for individual transistors in a circuit rather than trying to design a given circuit to be universally applicable to a range of transistor characteristic values.

Abstract: Microstrip transistor characteristic matching apparatus is illustrated which can be altered as to design frequency, phase of reflection signal coefficient and magnitude of reflection coefficient to optimize signal transmission to or from a given transistor. After adjustment, the apparatus can be analyzed to quickly determine the characteristics required for an in-circuit commercial version of such a device.

Abstract: Microwave circuit layout structure is disclosed for a diode mixer frequency converter. Each mixer port is provided by balun circuitry, and the diodes are isolated from, and on the opposite side of the substrate from, the primary circuits of the baluns. Single and double sideband versions are disclosed, including various combinations of dual and single baluns and porting structure.

Abstract: Microwave circuit layout structure is disclosed for a diode mixer bridge. The circuit layout structure is compact and symmetric, and enables short orthogonal equal length leads from a diode ring quad mixer bridge. The configuration also affords equal path lengths through the diodes to provide precise 180.degree. phase differential image frequency cancellation. The structure also affords precise and consistent mounting of the mixer bridge, to further improve performance.

Abstract: Microwave circuit layout structure is disclosed for a diode mixer frequency converter. The circuit layout structure is compact and symmetric, and enables coplanar diode lead connection.

Abstract: Microwave circuit layout structure is disclosed for a diode quad mixer frequency converter with separate, isolated sections, each supplied by a respective half of dual balun port structure. The circuit layout structure is compact and symmetric, and enables coplanar diode connection.

Abstract: A microwave frequency converter is provided with a diode mixer bridge having a balanced port connected to a dual balun. The dual balun is provided by two pairs of balanced secondary conductors juxtaposed a common primary conductor, each pair contributing to the field between balanced conductors leading to the mixer bridge. The dual balun and microstrip circuit layout enable a wider gap to be used between the balanced conductors to the bridge, which enables manufacturably cost efficient implementation.

Abstract: A low frequency diode mixer is provided in combination with simple, compact transformer circuitry. A four diode mixer interconnects three dual transformers. The mixer has a pair of separate, isolated two diode sections commonly servicing the first transformer and separately servicing the other two transformers.

Abstract: A balun coupled microwave frequency converter is provided by a mixer using a single diode pair with one port balanced and the other port unbalanced. The balanced port is provided by first and second coplanar conductors extending toward a common area and juxtaposed in spaced parallel relation with a transmission line interacting therewith to couple a field balanced between the first and second conductors across the common area. The unbalanced port to the mixer is provided by a third conductor. The diode pair is connected in series between the first and second conductors, and a point between the diodes is connected to the third conductor. One implementation is an up converter with an LO and an IF signal applied on the third conductor and input to the mixer to generate an RF signal between the first and second conductors and hence an induced output RF signal on the transmission line.

Abstract: A microwave frequency converter is provided by a single mixer of the diode-quad bridge type which circulates generated image frequency within the bridge. The bridge is connected between balun coupled RF microstrip conductors and unbalanced LO microstrip conductors. There is zero connection length between the diode pairs to reduce conversion loss by preventing a phase shift between the image frequencies. Mutual isolation is provided between the RF, LO and IF signals over a broad frequency range. In an alternate utilization, the converter accepts transposed RF and LO signals, for broader bandwidth operation. The circuit may also be implemented as an up converter.

Abstract: The present invention uses two interconnected baluns with the balanced output of one feeding a balanced input of the other. When this filter is used in conjunction with a signal frequency converter, the balun pair not only provides extremely effective bandpass filtering so as to pass the RF frequencies and not the IF frequencies but, in addition, provides a condition which appears to the IF as a nearly open circuit and thus provides a large amount of reflection or return of the IF signals to the signal converter so that the overall signal converter operation is more efficient in combination with the present invention than with any comparable known prior art signal isolating device.

Abstract: The present invention uses two interconnected baluns with the balanced output of one feeding a balanced input of the other. When this filter is used in conjunction with a signal frequency converter, the balun pair not only provides extremely effective bandpass filtering so as to pass the RF frequencies and not the IF frequencies but, in addition, provides a condition which appears to the IF as a nearly open circuit and thus provides a large amount of reflection or return of the IF signals to the signal converter. Through the use of additional grounding stubs, additional coupling means, increased separation between coupling means and separated ground planes each singularly or in combination, improved performance has been obtained as compared to the prior art.

Abstract: Microstrip technology is utilized in illustrating new and improved versions of baluns, hybrid junctions and half-wave balanced mixers and full-wave double balanced mixers.

Abstract: A dual balanced mixer frequency converter is disclosed which provides a low conversion loss by reactively terminating one of the leads on a combiner circuit such that all the image frequency signal power and/or part of the reflected receiver power is returned to the mixer. If this termination appears reactive at the image frequency response looking out from the mixer diode terminals, it will also reduce the noise appearing in the IF output signal.