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sm5bsz
Приєднався 12 сер 2013
This channel is about radio. Mostly software defined radio (SDR), but also fundamental aspects of radio. This channel has videos about installation and set-up of Linrad and various tests on different SDR hardware. There are also some videos about test equipment for measurement of receiver and transmitter performance.
This channel is for people interested in radio technology, particularly radio amateurs. I do my best to explain things in terms of basic physics and simple mathematics but in several videos a basic understanding of the Fourier transform is required.
Interference-fighting is becoming more important as man made intreference from computers, digital communication and switch power is becoming the limiting factors for radio reception. This channel has a couple of videos about interference fighting, and more will be added.
This channel is for people interested in radio technology, particularly radio amateurs. I do my best to explain things in terms of basic physics and simple mathematics but in several videos a basic understanding of the Fourier transform is required.
Interference-fighting is becoming more important as man made intreference from computers, digital communication and switch power is becoming the limiting factors for radio reception. This channel has a couple of videos about interference fighting, and more will be added.
nerds99
For nerds only! This is the 99th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. The channel 2 reference oscillator had significantly more phase noise than the one in channel 1. Increasing power made a significant improvement, but below 0.5Hz offset from the carrier channel 2 is still more noisy than channel 1. The improvement will make measurements significantly faster.
Переглядів: 142
Відео
nerds98
Переглядів 44021 день тому
For nerds only! This is the 98th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. There have been noise bursts - and finally I have found the problem. Teflon dielectric trimmer capacitors in LC circuits are now replaced by fixed capacitors and slug tuned inductors.
allan2
Переглядів 6683 місяці тому
Various measurements of Allan deviation and comparisons of results between TinyPFA with TimeLab, Linrad and Linrad with TimeLab. An error by a factor 1.4, the square root of two is found an corrected in Linrad.
nerds97
Переглядів 4064 місяці тому
For nerds only! This is the 97th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. Here I use a TinyPFA to measure Allan deviation. Results from Linrad agree reasonably well..
Allan
Переглядів 2694 місяці тому
I have added the computation of Allan deviation in Linrad. In this video I try to verify that the new code is correct by a comparison with the results from a HP5370A with TimeLab. Results are questionable. The 5370A is noisy in the short time scale while my Linrad setup is noisy in the long time scale. Only at tau about 20 seconds both systems see (perhaps) the noise from the test oscillator.
nerds96
Переглядів 2574 місяці тому
For nerds only! This is the 96th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. Here I focus on close range phase noise and how it looks in the time domain with Allan deviation and frequency vs time. Several problems with correlation measurements are discovered and correct...
sidebandnoise2
Переглядів 2415 місяців тому
Here the phase noise measured with a Rohde & Schwarz FSUP is compared to new measurements with Linrad. Agreement is very good except for an oscillator with high amplitude noise. An oscillator from Wenzel shows much lower phase noise at 0,1 Hz offset when the frequency control potentiometer is set to its end position. Filtering the DC supply to suppress AC down well below 0,1 Hz is important eve...
nerds95
Переглядів 5286 місяців тому
For nerds only! This is the 95th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. Here I continue to look for noise sources in my oscillator that starts in nerds80. The flat noise floor is good, -182 dBc/Hz, but the noise very close to the carrier is not. I find I need to re...
nerds94
Переглядів 1796 місяців тому
For nerds only! This is the 94th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. Here I improve the isolation between the oscillators in my correlation setup and find it was not necessary. Further I check flicker noise from the attenuators in the interferometer.
nerds93
Переглядів 2036 місяців тому
For nerds only! This is the 93rd in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. More on the low noise oscillator with two crystals. I am trying to reproduce the very good performance I saw initially with this design. I found reasons to modify my correlation setup before co...
nerds92
Переглядів 2,1 тис.8 місяців тому
For nerds only! This is the92nd in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. More on the low noise oscillator with two crystals.
nerds91
Переглядів 2,5 тис.9 місяців тому
For nerds only! This is the 91st in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. Here I rebuild my first 10 MHz 3-rd overtone oscillator which I have used for sideband noise measurements. As it turns out, the main problem was the stiffness of the PCB material used to build ...
nerds90
Переглядів 66110 місяців тому
For nerds only! This is the 90th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. Here I look at the influence of noise on the power supply on the phase noise of the two-crystal oscillator and discover why the amplifier in front of the soundcard needs to be DC-coupled. Sudde...
nerds89
Переглядів 60711 місяців тому
For nerds only! This is the 89th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. More on the low noise oscillator with two crystals. Phase noise: @1Hz -127 dBc/Hz @10Hz -156 dBc/Hz @200Hz -175 dBc/Hz @2kHz -182 dBc/Hz The advantage of using two crystals is small. 3 dB only ...
nerds88
Переглядів 467Рік тому
For nerds only! This is the 88th in a series of videos about sideband noise in oscillators, frequency multipliers, the components we use to build them as well as the tools used to measure sideband noise. More on the low noise oscillator with two crystals. Here I try to reduce the sensitivity to infrasound, low frequency changes in the air pressure. Some components were found to be sensitive, bu...