Abstract: The present invention provides a system and corresponding method for an oil-cooled high power amplifier system, such as an inductive output tube [“IOT”]. According to one preferred embodiment, the system has an IOT, a fluid passageway in thermal contact with the IOT, an oil-based fluid within the fluid passageway such that the oil-based fluid removes thermal energy from the IOT, an oil pump connected to the fluid passageway to circulate the oil-based fluid, and an oil heat-exchanger connected to the fluid passageway for removing the thermal energy from the oil-based fluid. The IOT preferably has a multistage depressed collector, and the oil-based fluid is preferably a commercially available transformer oil. In a preferred embodiment of the present invention, the oil-heat exchanger is connected to an external heat exchanger. The external heat exchanger has a cooling fluid passageway in thermal contact with the fluid passageway.

Abstract: A circuit to monitor ac line current through resistors employed to provide a ‘step start’ in a power supply, including means to monitor the current flowing through the step start resistors, comprising a peak detector, a sample and hold circuit, an analog to digital convertor and a microprocessor. The output of the current monitoring circuit may be employed to abort starting if abnormalities are sensed. The circuit may also be used to identify when the step start resistors need longer cooling time, and to continuously monitor current at times other than during starting. A timing circuit is also incorporated, which senses zero crossings of the voltage input to the power supply, so as to control the timing of the current monitoring circuit. The discrete circuits employed may be replaced by either a digital signal processor integrated circuit or a general-purpose computer implementing the same steps in a suitable algorithm.

Abstract: A lifting handle temporarily attaches to the water jacket of a plug-in liquid cooled IOT to facilitate installation, replacement, or removal of the IOT. The lifting handle includes two gripping surfaces that conform to the surface of the water jacket of a plug-in liquid cooled IOT. The gripping surfaces are hinged at their rear ends and clamped with a toggle clamp at the front ends. The gripping surfaces may be shaped to provide convenient handling during installation, replacement, or removal.

Abstract: A circuit and method for adaptive precorrection of first signals applied to RF signal combiners of a broadcast signal transmitter provides a sample of the combined signal output of the RF combiner and a sample of a second signal to a hybrid so as to cancel from the combined signal the second signal, and to apply the resulting signal sample representing the first signal to an adaptive precorrector which precorrects the first signal before it is applied to the RF combiner. The circuit and method can be used with a two signal combiner, or with a multiple signal combiner.

Abstract: An apparatus for doubling the amount of power that can be safely applied to a circulator-based isolator, which is made up of an input hybrid which receives an RF signal and outputs two divided RF signals, a Y-junction circulator that receives one of the divided RF signals at one of the circulator ports and outputs it at another circulator port, an output hybrid which receives the two divided RF signals, combines them, and sends them on, the output hybrid simultaneously receiving a returned signal, dividing it, and outputting two divided returned signals, one divided returned signal going to the circulator and the other divided returned signal going directly to the input hybrid, a phase retarding circuit which takes the half of the divided returned signal that went back to the circulator and retards its phase by 180 degrees and sends it back to the circulator, where it goes to the input hybrid as well, to be recombined with the other half of the returned signal and attenuated.

Abstract: A method and apparatus are provided for allowing two different television signals to be combined and sent to a common propagation device, such as a tower antenna. The apparatus utilizes a number of appropriately loaded hybrids, hybrid waveguide junctions, or other appropriate equivalent devices to combine the signals in such manner that there is a minimum of intersignal interference or distortion. The apparatus utilizes bandpass/reject filters and notch filters in conjunction with the hybrids to achieve the desired results. A television broadcast system using the hybrid combining apparatus is also provided.

Abstract: A method and system for correcting errors introduced by a non-linear amplifying device to an input signal inputted to the device. A Look-Up Table (LUT) stores error correction values indexed against input signal amplitude values and input signal frequency values. The amplitude and frequency of an input signal to be inputted to the non-linear amplifying device are measured, and stored error correction values corresponding to the measured amplitude and frequency are retrieved from the LUT and used to modify the input signal accordingly.

Abstract: A controller-based radio frequency amplifier method and module are employed in a modular transmission system in which respective of the controller-based radio frequency amplifier modules amplify a portion of a signal that is input into the system. Each amplifier module includes an amplifier submodule have a plurality of discrete amplifiers arranged in an amplifier chain, a processor submodule is configured to control a level of the amplified output signal that is output from each amplifier module, a power supply module, and an enclosure. The processor submodule is configured to control the discrete amplifiers in the amplifier submodule such that the module may be removed or added to the system without damaging the power amplifier module or other system components.

Abstract: A computer program product is configured to control a modular transmission system having a control processor and at least N power amplifier modules, each having a controller submodule, wherein the system receives an input signal which may be a single carrier or multiple carriers. The signal is passed to a one-by-N divider which divides the signal N ways. Each of the N divided signals are independently amplified by the power amplifier (PA) modules "slices" (i.e., PA modules) that includes an RF amplifier module, a microcontroller module, and a power supply module, all of which are tightly coupled via a plurality of signal, power, control, and status connections. Each the PA slices amplifies its respective input signal and outputs a respective radio frequency output signal at a predetermined power level as controlled by the microcontrol module, the driver, and the system controller, or a network manager via a system input/output interface.

Abstract: A modular broadband transmission system and method include an input signal connector that receives an input signal which is then divided into N parts and amplified with an amplifier have N power amplifier modules. Outputs of the N power amplifier modules are passed through transmission lines and to a radial combiner that combines the outputs. The radial combiner, transmission lines and power amplifier modules are configured such that if one of the power amplifier modules fails, the other power amplifier modules may still operate acceptable well, with minimal impact on total output power. An output of the amplifier is provided to a coupler that measures a power level of the output signal and feeds the measured power level back to a controller where the controller adjust an overall output power based on the number of the power amplifier modules that are functioning properly.

Abstract: Apparatus is provided for allowing two high frequency signals from two separate sources to be combined for simultaneous propagation through a common propagation medium such as an antenna or transmission line, while maintaining isolation between the signals at the inputs of the sources and preventing unwanted interference and resulting distortion. The apparatus includes an orthogonal mode converger which receives two combined electromagnetic energy waves having orthogonally disposed electric field vectors and incrementally converges them to the same direction through a varying cross-section waveguide structure.