RF Electronics Chapter 3: Transformers and Hybrids Page 56
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
Transformer Hybrids
In a hybrid, the input power at port 1 is split two
ways to adjacent ports 2 and 3. Port 4, opposite
the input port is isolated from the input port, and
should have no energy going to it. A hybrid can
thus be used as a power splitter.
Hybrids are normally symmetrical and bi-
directional. Port 2 can thus also be used as an
input, and under those conditions, half the power
appears at port 1 and the other half appears at port
4. Under these conditions, port 3 is isolated. If we
now apply another input signal at port 3, that will
also split two ways with half appearing at port 1
and the other half at port 4. For most hybrids, the
phase angle at port 4 is 180 degrees out of phase
for inputs at either port 2 or port 3, so that if equal signals are applied to ports 2 and 3,
the sum of the signals will appear at port 1 and the difference will appear at port 4. If the
signals applied to port 2 and port 3 are the same, the powers are combined at port 1. A
hybrid can thus be used as a power combiner as well.
Figure 3.12. Audio transformer hybrid.
Transformer hybrids like the ones in figure 3.12 are used in telephony networks, where
the signals to and from the normal telephone are sent in both directions on two wires.
In
Out1
Out2
1
2
3
4
Figure 3.11. Hybrid.
RF Electronics: Design and Simulation
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