One question. One answer. Zero noise.
One RC time constant is the time required to charge a capacitor to 63.2% of the applied voltage or discharge it to 36.8% of its initial voltage.
Excessive closed-loop gain and Q can make an active filter ring or become unstable.
Frequency-hopping spread spectrum moves the transmitted carrier rapidly among frequencies according to a pseudorandom sequence.
The Smith chart is built from families of constant-resistance circles and constant-reactance arcs.
For FM, modulation index is the ratio of peak frequency deviation to the modulating signal frequency.
Extremely short CW rise and fall times contain strong high-frequency components that create audible key clicks and broaden the transmitted spectrum.
A phase-locked loop compares phase with a reference and adjusts a voltage-controlled oscillator through a filtered error signal.
A Canadian amateur operating in the United States receives the operating terms and conditions of the Canadian license, but may not exceed US Amateur Extra privileges.
A grounded-grid amplifier presents a relatively low impedance at its input.
The official E2C08 source lists Worked All States contacts among those that may be confirmed through LoTW.
OFDM uses many subcarriers whose frequency spacing is selected so their spectra remain mathematically orthogonal, allowing efficient overlap.
Increasing loop turns or enclosed area increases magnetic flux linkage and therefore increases induced output voltage.
In Figure E6-2, symbol 6 is the Schottky diode.
At RF, current crowds toward the conductor surface. As frequency increases, the effective cross-sectional area carrying current decreases, so resistance increases.
An automatically controlled station may transmit third-party communications only when using RTTY or data emissions.
An automatic notch filter looks for steady narrow carriers. A CW signal can resemble the interference it is designed to remove, so the desired CW may also be notched out.
A coding rate of 3/4 means three quarters of the transmitted bits carry payload information and one quarter is forward-error-correction overhead.
Bipolar transistor beta is current gain: the change in collector current divided by the corresponding change in base current.
The NTSC fast-scan television standard uses 525 horizontal lines per frame.
Q65 differs from JT65 by averaging multiple receive cycles, improving recovery of very weak or varying signals.
Comparator hysteresis creates separate switching thresholds for rising and falling inputs, preventing small amounts of noise from repeatedly toggling the output.
A receiver preselector is a tunable front-end filter that rejects signals outside the band being received.
The horizontal resistance axis is the only straight line in the Smith chart figure.
In the ideal op-amp model, open-loop gain is treated as frequency independent.