Waveguide Isolator and Circulators: It often happens at microwave frequencies that coupling must be strictly a one-way affair. This applies for most microwave generators, whose output amplitude and frequency could…
Wideband Antenna Types: It is often desirable to have an antenna capable of operating over a wide frequency range. This may occur because a number of widely spaced channels are…
Directional High Frequency Antenna: Directional High Frequency Antenna are likely to differ from lower-frequency ones for two reasons. These are the HF transmission/reception requirements and the ability to meet them.…
Antenna Coupling: Antenna Coupling : Low and medium frequency antennas are the ones least likely to be of resonant effective height and are therefore the least likely to have purely…
Fundamentals of Transmission Lines: Fundamentals of Transmission Lines (in the context of this book) are considered to be impedance-matching circuits designed to deliver power (RF) from the transmitter to the antenna,…
Automatic Frequency Control Block Diagram: Automatic frequency control: As previously we see, the heart of an AFC circuit is a frequency-sensitive device, such as the phase discriminator, which produces a…
Squelch Circuit: Squelch (muting):Â When no carrier is present at the input, i.e., in the absence of transmissions on a given channel or between stations, a sensitive receiver will produce a…
Delayed Automatic Gain Control: Delayed Automatic Gain Control: Simple AGC is clearly an improvement on no AGC at all, in that the gain of the receiver is reduced for strong…