Rigol DSO useful bandwidth ?

[Phil Allison]

** Hi to all,

that "dumped" Rigol DSO continues to exceed my expectations.

The latest surprise came about when I investigated a high level of noise in
the trace at high gain settings - not inherent in the DSO mind you, but
only when attached to other devices on my bench.

Soon found several mV of RF signal being picked up around 98 to 100 MHz -
with the time base set to 20nS the counter function locked onto it
reasonably well.

A check with a radio scanner turned up a very strong signal on 98.5 MHz
from "2000FM" - broadcasting from the Optus Tower in North Sydney with 25
kW of ( ERP ?) power.

http://www.2000fm.com/tech_spec.htm

( The mono music program was of telephone quality - how can they get away
with that ? )

I tried the FFT function and the DSO presented a nice plot of the VHF radio
spectrum - clearly showing ABC2's carrier on 64 MHz and extending right
through and beyond the FM band.

When a 12MHz square wave oscillator module was tried, it clearly showed odd
harmonics right up to the 11th and maybe 13th.

That's 156 MHz !!

Anyone got a VHF gen to see what the real limit is ??


..... Phil

 

[Phil Allison]

"Phil Allison"

Anyone got a VHF gen to see what the real limit is ??

** Done that myself now.

1. The upper limit of the "counter" function of my DS1052E is 264.25 MHz.

2. The upper limit of a viewable, synchronised wave is circa 400MHz.

3. The FFT works to beyond 260 MHz, but beware of frequency aliasing.

4. The digital filter works as shown on the screen guides.


Not too shabby for cheap, nominal 50MHz scope..............




..... Phil

 

[David L. Jones]

"Phil Allison"

** Done that myself now.

1. The upper limit of the "counter" function of my DS1052E is 264.25 MHz.
2. The upper limit of a viewable, synchronised wave is circa 400MHz.

3. The FFT works to beyond 260 MHz, but beware of frequency aliasing.

4. The digital filter works as shown on the screen guides.


Not too shabby for cheap, nominal 50MHz scope..............

Very interesting, thanks for sharing Phil.
Someone on my EEVblog forum posted a measured frequency response of the
DS1052E, as measured by the on-screen signal level measurement readout
function.
http://polomobil.files.wordpress.com/2009/10/rigol15.png
and
http://polomobil.files.wordpress.com/2009/10/rigol15.png

Dave.

 

[Phil Allison]

"David L. Jones"
<

Someone on my EEVblog forum posted a measured frequency response of the
DS1052E, as measured by the on-screen signal level measurement readout
function.

** That claim makes no sense.

The on screen ( rms etc) voltage readout relies on the sampled data points.



.... Phil

 

[JW]

2. The upper limit of a viewable, synchronised wave is circa 400MHz.

Presumably with decreased vertical amplitude. Any idea how much? On a
50Mhz scope I would think it's quite a bit.

 

[N2CUA]

Funny you should mention that ..
I used a couple of handheld radios and put an antenna on
CH1 of the scope and was seeing waveforms up at 440 MHZ ..
and .. get this .. I turned on the "Counter" function which is a
freq counter thats added to the display and it was MEASURING
the 440 MHZ !! LOL
Not too incredibly accurate .. but the fact that it saw it, displayed it
albeit with attenuation, and measured it was pretty nice.
This was on the DS1102E 100Mhz Scope.

Randy - N2CUA

** Hi to all,

that "dumped" Rigol DSO continues to exceed my expectations.

The latest surprise came about when I investigated a high level of noise in
the trace at high gain settings - not inherent in the DSO mind you, but
only when attached to other devices on my bench.

Soon found several mV of RF signal being picked up around 98 to 100 MHz -
with the time base set to 20nS the counter function locked onto it
reasonably well.

A check with a radio scanner turned up a very strong signal on 98.5 MHz
from "2000FM" - broadcasting from the Optus Tower in North Sydney with 25
kW of ( ERP ?) power.



( The mono music program was of telephone quality - how can they get away
with that ? )

I tried the FFT function and the DSO presented a nice plot of the VHF radio
spectrum - clearly showing ABC2's carrier on 64 MHz and extending right
through and beyond the FM band.

When a 12MHz square wave oscillator module was tried, it clearly showed odd
harmonics right up to the 11th and maybe 13th.

That's 156 MHz !!

Anyone got a VHF gen to see what the real limit is ??


..... Phil