it is also possible todetect the received data with an analog demodulator right afterthe channel select filter.A frequency discriminator [3], phase-locked loop(PLL)-based detector [3], differential or delay line dis-criminator [4], [5], or zero-crossing detector [6] can be usedin GFSK ...
Compared to the simple diode needed to demodulate AM radio signals, the detector circuits used for FM are slightly more complicated. Wrapping your head around phase detectors, ratio detectors, discriminators, and quadrature detectors can be quite an exercise. There’s another demodulation method that...
overall PLL integrated noise level and, thus, the modulation bandwidth. For FSK data, the PLL loop bandwidth can be set as low as 1.0 × the data rate without affecting the modulation quality. There-fore, to cater to S, T, and R modes, the PLL loop bandwidth should be set to 100 ...
The earth's ionosphere induces an additional phase change and, under disturbed conditions, a random complex modulation. To demodulate the signal the slowly varying carrier frequency o陇set must be estimated.CarranoGunterParrish
A faster and simpler approach is to use a transceiver with an automatic PA ramp. The ADF7021 has a programmable ramp for which both the number of steps and duration of each step can be set by the user. Communication Protocol Considerations Analog Devices is currently in the process of ...
Yes, this was probably the first I looked at, but its phase comparators based on logic gates are not suitable for noisy signals (the purpose of the PLL here is to average out off-carrier noise like in a lock-in amplifier). It can also be configured with an external phase detector, thi...
Phase-locked loops are widely employed in radio, telecommunications, computers and other electronic applications. They can be used to demodulate a signal, recover a signal from a noisy communication channel, generate a stable frequency at multiples of an input frequency (frequency synthesis), or dist...
In addition to stabilizing a particular communications channel (keeping it set to a particular frequency), a PLL can be used to generate a signal, modulate or demodulate a signal, reconstitute a signal with less noise, or multiply or divide a frequency. FIG. 1 illustrates the classic PLL ...
A PLL can be used to maintain a well-defined phase, and hence frequency, relation between two input sources. PLLs can have an oscillator that constantly adjusts to match the frequency of an input reference clock signal. Example PLLs can be used to generate, stabilize, modulate, demodulate,...
If the number of satellites is large enough (more than four), then the measured pseudo-ranges can be processed to determine the user location (e.g., X, Y, and Z coordinates) and to reconcile the variations in the time scales. Finding the user location by this process is often referred...