Abstract:
This application describes an arrangement for matching the output impedance of an amplifier to its load. The amplifier comprises two active stages having mutually inverse output impedances whose respective magnitudes are, preferably, at least an order of magnitude greater than and at least an order of magnitude less than the impedance of the external load circuit to which the amplifier is connected. The lower output impedance stage is connected to a first load impedance through one winding of a two-winding transformer. The higher output impedance stage is connected to ground through the other transformer winding. A second, impedance-matching load is connected in shunt with either one of the two transformer windings. By controlling the relative amplitude and phase of the signals derived from the two stages, the signal current can be coupled to either one or the other of the two load impedances, or to both. Arrangements for increasing the amplifier gain and obtaining a match at the amplifier input are also described.
Abstract:
This application discloses the manner in which a constant voltage source and a phase coherent constant current source can be connected to a common load, and how the power distribution between the two sources can be controlled by varying the ratio of the two output signals. The sources can be phase locked oscillators, or two amplifying stages coupling a common signal source to a common output load.
Abstract:
This application describes an n-port circulator comprising n identical circuit units arranged in a closed loop configuration. Each unit is a three terminal circuit including two transistors and two equal, impedance-matching impedances. The first terminal is connected to the base of the first transistor, and to the emitter of the second transistor through one of the impedances. The second terminal is connected to the collector of the second transistor, and to the emitter of the first transistor through the other impedance. The third terminal is connected to the collector of the first transistor, while the base of the second transistor is grounded. The units are interconnected such that the third terminal of each is coupled to the first terminal of the next adjacent unit in the loop. The second terminals of the units constitute the ports of the circulator.
Abstract:
The signal at the output of a signal amplifier is compared, in a differential amplifier, with the input signal to the signal amplifier. Any difference between these two voltages causes an error-correcting voltage to be generated across an impedance in series between the signal source and the signal amplifier input port. This error-correcting voltage is added to the input signal in phase to cancel the output signal error. By using a differential amplifier to produce the error signal, there is no feedback to the signal source, resulting in a high degree of stability.
Abstract:
Frequency-shaping of the gain characteristic of a feed-forward, error-corrected amplifier using main and error amplifiers having essentially flat, or frequency-independent gain characteristics, is achieved by tapering the power division characteristics of: the input coupler, which extracts a reference signal component from the input signal; the sampling coupler, which compares the output from the main amplifier with the reference signal to form an error signal; and the error injection coupler, which injects the error signal into the main signal path. In a second embodiment of the invention, the band-shaping burden is shared between the amplifiers and the couplers.
Abstract:
A variety of amplifiers are described, each of which comprises two active stages having equal coefficients of transmission, and mutually inverse input and output terminal impedances whose respective magnitudes are at least an order of magnitude different than that of the external circuits connected thereto. Input and output transformer networks couple the two stages to a common signal source and to a common output load.
Abstract:
This application describes a coupling circuit for coupling one or more signal sources to a common load without disturbing any of the coupled circuits. Each coupling circuit comprises a pair of amplifiers and a two-winding transformer. One amplifier, whose output impedance is much less than the load impedance, is connected to the transformer secondary winding. The other amplifier, whose output impedance is much larger than the load impedance, is connected to a center-tap on the transformer primary winding. The load and a matching impedance are connected to opposite ends of the primary winding. When more than one source is to be coupled to the load, the transformer primary windings are connected in series. A similar arrangement can be used at the input end of each amplifier. The suggested network can be used as the error injection network of a feed-forward amplifier.