Products > Test Equipment
Low cost logic analyzer probe for Rigol MSO5000 EasyEDA project
S. Petrukhin:
--- Quote from: nullik on December 28, 2020, 12:12:38 am ---
--- Quote from: calippo on November 28, 2020, 10:43:42 pm ---Any feedbacks?
As Kicad user, I was planning to pursue the JLCPCB option too. :)
--- End quote ---
I checked design in KiCad and think all fine. Also I got my PCBs with this design.
Now I waiting electronic componets for checking device.
After I get the EC and check device, I will write the results here.
The design is not perfect and can still optimize pcb.
I will check the delay in differential pairs, if i found mistakes then I make my own PCB.
--- End quote ---
It looks like you used the hydrabus design. As discussed here, and according to the results of my tests, its changes will not interfere with the work, but for the bandwidth of LA MSO5074 they are not it does not matter.
nullik:
--- Quote from: S. Petrukhin on December 28, 2020, 12:46:48 am ---It looks like you used the hydrabus design. As discussed here, and according to the results of my tests, its changes will not interfere with the work, but for the bandwidth of LA MSO5074 they are not it does not matter.
--- End quote ---
Yes, I use his design. Perhaps you are right. But I know strict requirements high freq designs like USB bus.
Differential pairs work only if they have the same delay. And they become very easily ineffective if this rule is violated.
A simple example of a USB bus, with bad cable it can work ustable, lose
synchronization, data transfer speed drops.
The correct way is not to align the length of the lines, the correct is to align their delays.
Also for a better high freq design and low noise, you need to have at least a 4-layer PCB.
At high frequencies, we are very dependent on reactive capacitances and inductances.
S. Petrukhin:
--- Quote from: nullik on December 28, 2020, 02:53:14 am ---
--- Quote from: S. Petrukhin on December 28, 2020, 12:46:48 am ---It looks like you used the hydrabus design. As discussed here, and according to the results of my tests, its changes will not interfere with the work, but for the bandwidth of LA MSO5074 they are not it does not matter.
--- End quote ---
Yes, I use his design. Perhaps you are right. But I know strict requirements high freq designs like USB bus.
Differential pairs work only if they have the same delay. And they become very easily ineffective if this rule is violated.
A simple example of a USB bus, with bad cable it can work ustable, lose
synchronization, data transfer speed drops.
The correct way is not to align the length of the lines, the correct is to align their delays.
Also for a better high freq design and low noise, you need to have at least a 4-layer PCB.
At high frequencies, we are very dependent on reactive capacitances and inductances.
--- End quote ---
This has already been discussed. Rigol engineers did not even bother to install load resistors on the receiver side and did not turn them on inside the FPGA, and you will worry about leveling a couple of centimeters of the track. It's like covering up the gold of the thatched roofs. :)
You create more inductance and capacitance by looping the track. :)
nullik:
I checked KiCad logic probe. All works fine.
I gave my pcb to people. I will be making the next version of the probe with a different plug on the output so that I can use high frequency shielded wires from dslogic.
https://www.dreamsourcelab.com/shop/accessories/shielded-fly-wires/
S. Petrukhin:
--- Quote from: nullik on January 13, 2021, 06:02:01 am ---I checked KiCad logic probe. All works fine.
I gave my pcb to people. I will be making the next version of the probe with a different plug on the output so that I can use high frequency shielded wires from dslogic.
https://www.dreamsourcelab.com/shop/accessories/shielded-fly-wires/
--- End quote ---
Shielded doesn't mean high-frequency. :) High-frequency lines must be matched.
And for shielded wires, you can use double female pin, because each input has its own personal Gnd pin in an existing connector.
Get a savings of 23 bucks. :)
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