Abstract: In a diversity signal combiner, the weaker of the two signals is attenuated an amount that varies as a function of the phase angle between the two signals. When the phase angle is small, the attenuation is small and the two signals add together. As the phase angle increases, the attenuation of the smaller of the two signals increases. For phase angles between 90 and 270 degrees, the contribution of the smaller signal is negligible. In digital systems, improvements in the bit error rate can be realized by introducing a 180 degree relative phase shift in the wavepath of the weaker signal whenever the phase angle exceeds a specified threshold.

Abstract: This application describes a method and apparatus for measuring the transmission characteristics of a class of nonlinear two-ports containing physically inseparable reactive networks, but which can be characterized by an equivalent network comprising input and output linear reactive networks separated by a resistive nonlinear network. In accordance with the method, three signals, f.sub.1, f.sub.2 and f.sub.3, are applied to the test network where signals f.sub.2 and f.sub.3 are variable and differ by a relatively small amount .DELTA.f. So related, the third order intermod frequency, f.sub.p =f.sub.1 -f.sub.2 +f.sub.3, becomes a constant f.sub.p =f.sub.1 +.DELTA.f. It is further shown that the magnitude of the output voltage V.sub.p at frequency f.sub.p is proportional to the square of the magnitude of the input network transfer function H.sub.A (f).

Abstract: The problems associated with large bandwidth requirements and of precisely controlling the relative magnitudes of the distortion components generated in predistorters are resolved in a bridge-type cuber circuit (10). The cuber comprises a resistive bridge (R.sub.1, R.sub.2, R.sub.3, R.sub.4) which includes a pair of oppositely-poled diodes (D1, D2 and D3, D4) connected in parallel with the resistor (R.sub.1, R.sub.3) in each branch (25, 26) of one pair of opposite branches of said bridge. The parameters of the cuber, which is balanced with respect to fundamental frequency signals, are adjusted so that predominantly third order intermodulation components are generated, and an impedance match with the signal source is obtained.The cuber circuit is used in a predistorter for cancelling third order distortion components produced in nominally linear amplifiers.

Abstract: A line device for transmission lines having coaxial cables for the transmission of signals, in particular digital signals or analog signals, employs an input equalizer in the form of a line section connected in parallel or in series to the transmission path, a first switch or dividing network for dividing the transmission path into a communications transmission path and a long distance current supply path, a regenerator in the communication transmission path, a series circuit connected in the long distance supply path including a first low pass filter, an element for producing a voltage drop for the current supply of the regenerator and a second low pass filter. A second switch or dividing network rejoins the communications and long distance supply paths and an output equalizer in the form of an additional line section is connected in parallel to the transmission path or in series with the transmission path.