Zajimava zavada osciloskopu Hantek DSO5062B

balu@home balu na
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 

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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