Ad
related to: low phase noise amplifier design
Search results
Results from the WOW.Com Content Network
A low-noise amplifier (LNA) is an electronic component that amplifies a very low-power signal without significantly degrading its signal-to-noise ratio (SNR). Any electronic amplifier will increase the power of both the signal and the noise present at its input, but the amplifier will also introduce some additional noise.
The ideal LNB, effectively a perfect amplifier, would have a noise figure of 0 dB and would not add any noise to the signal. Every LNB introduces some noise but clever design techniques, expensive high-performance low-noise components such as HEMTs and even individual tweaking of the LNB after manufacture, can reduce some of the noise ...
In signal processing, phase noise is the frequency-domain representation of random fluctuations in the phase of a waveform, corresponding to time-domain deviations from perfect periodicity . Generally speaking, radio-frequency engineers speak of the phase noise of an oscillator, whereas digital-system engineers work with the jitter of a clock.
The f c for an amplifier depends on the actual configuration used, because radio-frequency and low-frequency negative feedback can have an effect on f c. So for accurate results, f c must be determined from added noise measurements on the amplifier using R.F., with the actual circuit configuration to be used in the oscillator.
A lock in amplifier uses a multiplier and a low pass filter to compare a reference signal against a noisy signal. A lock-in amplifier is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment. Depending on the dynamic reserve of the instrument, signals up to a million times smaller than noise ...
Thus, valves with low noise at high frequency do not necessarily have low noise in the audio frequency range. For special low-noise audio valves, the frequency at which 1/f noise takes over is reduced as far as possible, maybe to something like a kilohertz. It can be reduced by choosing very pure materials for the cathode nickel, and running ...
Very Low Phase Noise Vackar VFO for HF Transceivers. (Little variation from G3PDM's design. Very low phase noise claim is dubious; NF = 20 dB?) CMOS Implementation of Voltage Controlled Oscillator Quote: "...[pdf-page 30]...And here is the winner. If you want to build a very stable, low phase noise, and low spurious VCO, definitely Vackar VCO ...
The first amplifier in a chain usually has the most significant effect on the total noise figure because the noise figures of the following stages are reduced by stage gains. Consequently, the first amplifier usually has a low noise figure, and the noise figure requirements of subsequent stages is usually more relaxed.
Ad
related to: low phase noise amplifier design