Zajimava zavada osciloskopu Hantek DSO5062B
balu@home
balu na k-net.fr
Pondělí Duben 22 08:18:16 CEST 2013
Ak som to spravne pochopil tak je to odlisny sposob spracovania. Nikdy
som nad tym nerozmyslal tak som si musel zobrat na pomoc wikipediu :-)
Uplne obycajny digitalny osciloskop len sprosto navzorkuje signal a
zobrazi ho. Navzorkuje dalsi a zobrazi.
U phosphor pisu ze sa pouziva akasi umela zotrvacnost v zobrazovani aby
si tam videl aj glitche a ine iregularity signalu. Potialto som to
pochopil :-) Okrem toho pisu ze sa pouziva uplne iny sposob spracovania
signalu aby bol osciloskop rychlejsi a mal mensi dead time, toto som
zatial nepochopil. Podla vsetkeho to bola nova technologia zavedena u
prvych cislicovych osciloskopoch a dnes sa to pouziva uz na vsetkych
slusnych masinach akurat to uz nezdoraznuju.
A disadvantage of digital oscilloscopes is the limited refresh rate of
the screen. On an analog oscilloscope, the user can get an intuitive
sense of the trigger rate simply by looking at the steadiness of the CRT
trace. For a digital oscilloscope, the screen looks exactly the same for
any signal rate which exceeds the screen's refresh rate. Additionally,
it is sometimes hard to spot "glitches" or other rare phenomena on the
black-and-white screens of standard digital oscilloscopes; the slight
persistence of CRT phosphors on analog oscilloscopes makes glitches
visible even if many subsequent triggers overwrite them. Both of these
difficulties have been overcome recently by "digital phosphor
oscilloscopes," which store data at a very high refresh rate and display
it with variable intensity, to simulate the trace persistence of a CRT
oscilloscope.
Digital phosphor oscilloscopes
Digital phosphor oscilloscopes (DPOs) were introduced by Tektronix in
the late 1990s. DPOs employ a parallel processing architecture rather
than the serial processing architecture of other types of digital
oscilloscopes. This allows DPOs to capture transient events while
maintaining a large bandwidth. With the use of parallel processing, the
display permits intensity information to be seen in real time.
The first stage of the parallel-processing unit is a vertical amplifier,
like that of digital storage oscilloscopes. The second stage continues
to mimic that of a DSO: the signal is sent to an ADC. After the ADC,
however, the processing architecture varies. A DSO captures waveforms in
a serial manner. This generates a "holdoff" time, in which the
oscilloscope can not record any activity. The speed of the
microprocessor thereby limits the rate at which waveforms can be
captured. A DPO rasterizes the digital waveform into a digital phosphor
database, which is continually updated. Then, about every 1/30th of a
second, an image of the signal is sent to the display. By directly
rasterizing the data and copying it to display memory from the digital
phosphor database, the rate determining step is no longer the speed of
the microprocessor.
The "phosphor" of the DPO is purely electronic. The digital phosphor
database is composed of many cells which correspond to single pixels
within the display. Each time a cell is touched by the waveform,
intensity information accumulates. The DPO can display the information
in terms of contrasting colors.[5][6]
On Apr/22/2013 8:00, Kručinský Ladislav wrote:
> Ahoj, Balu,
> zaujal mě ten název: Digital Phosphor Oscilloscope...
> To je k čemu dobré to slůvko "Phosphor" ?
>
> Zdravím
> Kručinský
>
>
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