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attila

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Posts posted by attila

    Logic Detector as trigger in Scope. Is it possible?

    in Test and Measurement

    Posted

    Hi @m72

    After adding the Order option in Logic Analyzer (splitting the Input selection in two) I have forgotten to update the Protocol/Logic Analyzer to set the Order option automatically.

    Thank you for the observation, it is fixed for the next release.

    On 9/13/2019 at 7:46 PM, m72 said:

    Digital Discovery, WaveForms from 3.11.18, Windows 7 x64.

    When allow "Logic Analyzer" from "Protocol" by default it change DIO24 -> DIN0 (mode 800 MHZ, DIO0..7).
    If start "Logic Analyzer" at "200 MHz, DIN0...DIN23, DIO24...DIO31" it change sample rate "100...400MHz" -> "800 MHz" and change DIO24 -> DIN0. 
    If start "Logic Analyzer" at "400 MHz, DIO24...DIO39" it change sample rate "100...400MHz" -> "800 MHz" and make DIO >= 32 "not available". 
    And after that "800 MHz" -> "400 MHz" moves DIO32 -> DIO24 and DIO33 also to DIO24.

     

    Logic Detector as trigger in Scope. Is it possible?

    in Test and Measurement

    Posted

    Hi @m72

    This looks like a digital issue in the ADC.
    Have you used for this tests the WF v3.11.23 I sent you in private message?

    On 9/13/2019 at 7:07 PM, m72 said:

    Hello!

    Just tested it with simplest settings (attenuation 1X, 50 ns/div, zero signal). Only offset on the screen is changed.
    Scope1 ... Scope3.
    1. It happens only with second channel.
    2. When offset is [-2.34V ... -1.76V].
    3. At the borders noise is like a rare peaks. At the center like as an ADC input is overloaded.
    4. Peaks values are -7.6V & +7.6V.

     

    Logic Detector as trigger in Scope. Is it possible?

    in Test and Measurement

    Posted · Edited by attila

    Hi @m72

    You have in private message a software version which changes a bit the digital timings.
    Please install this, reconnect the device to make sure it will get reconfigured and start the application. Let me know if this solves the issue.

    The scope inputs are rated for up to +/-50V, but it should survive higher voltages due the 820k series resistor before the 7.5-20mA protection.
    High voltages (with energy) usually damage the gain selector analog switch, which leads to DC reading.
    https://reference.digilentinc.com/reference/instrumentation/analog-discovery-2/reference-manual#scope_input_divider_and_gain_selection

    The attenuation option is intended to scale the scope readings, it is not a device feature. For instance when you use a 10x scope probe (9M series), the scope input will actually get 1/10 of voltage. Specifying 10x attenuation the software will multiply the readings by 10, to compensate this. You can also use this to reflect external voltage dividers, amplifiers...

    Edit:
    The calibration adjust the amplitude and offset.

    Logic Detector as trigger in Scope. Is it possible?

    in Test and Measurement

    Posted

    Hi @m72

    This may look like a digital issue, from ADC to FPGA... but i don't it is since we should see similar glitch on the upper side too.

    Could you provide detail about the experiment?
    I see you have set 10x probe... Are you using (single ended) BNC probe at 10x ?

    In case you are using differential input with high common mode voltage, the signal might enter in limitation or clamping starts to act, which also depends on the offset:
    https://reference.digilentinc.com/reference/instrumentation/analog-discovery-2/reference-manual?redirect=1#scope_driver
    https://reference.digilentinc.com/reference/instrumentation/analog-discovery-2/reference-manual?redirect=1#scope_signal_scaling

    The highlighted "noise band" indicates high frequency signals (noise, glitch), above current sampling rate, which indicates some analog issue:

    image.thumb.png.d0e9c276f6fa3ce717918177555188e3.png

     

    Logic Detector as trigger in Scope. Is it possible?

    in Test and Measurement

    Posted

    Hi @m72

    The 1kHz is generated from the 100MHz system clock with 50% duty.
    The 1.1kHz is actually generated as 1.099989kHz with 49.9945% duty. Due to this the 180* phase, the middle falls in low level which gets used as initial value.
    For the next release I have modified the duty to round up, so the 1.1kHz will have 50.005499945% duty and the 180* phase will start high.

    I'm also adding negative delay for the next version.

    Thank you for the observation.

    Current version:
    image.thumb.png.c1b05c22b6534b66c837620bfe8c7953.png

     

    Next version:
    image.thumb.png.02dcd89b5386d9731dffe538f08fe221.png

    Logic Detector as trigger in Scope. Is it possible?

    in Test and Measurement

    Posted

    Hi @m72

    I have fixed the "pit top" for next version.

    I was unable to reproduce the crash. If you add multiple interpreters (Bus,I2C,SPI,UART...) it will use more memory and process the capture slower...

    The DD ram is 4Gbit (256MB). 
    With 8 bit sampling (input: 800MHz x8) you can capture in ram 256M samples, with 16 bit (400MHz x16) 128M, with 32 bit (100-200MHz x32) 64M (67108864).
    At lower rate you can capture up to 100Mi samples. In this case the data is streamed over USB, which could lead to sample lost due to congestion.
     

    Analog Discovery 2 vs Raspberry Pi 3

    in Test and Measurement

    Posted · Edited by attila

    Hi @Grimmers

    The Raspberry Pi 4 Model B is working well with the Analog Discovery 2 when connected to the USB 3 (blue) ports. It was running continuously for more than 24 hours.
    The connection to the device over the USB 2 (black) ports dropped after 6-12 hours.
    It looks like the problem was caused by the external USB hub. After connecting the AD2 directly to RPi4B USB 2.0 port it is working since 2 days.

    image.png.136c7dc8a77eb34e934775a96831f8f9.png

    Network Analyzer versus Impedance Analyzer

    in Test and Measurement

    Posted · Edited by attila

    Hi @Andras

    A. Comparing two different tools might not be the best option, it could give different results.

    B. At the moment the Impedance Analyzer interface takes control over the Supplies and DIO lines to control the IA Adapter.
    On the Adapter the negative supply and some DIO lines are unused.
    In the next software version I will add option to be able to control these.
    Having these you could use a small signal relay with ~5V control, similar to the ones on IA adapter but non-latching, to switch between the measured and control DUTs.
    https://reference.digilentinc.com/_media/reference/instrumentation/analog_discovery_impedance_analyzer_sch.pdf


    Edit:
    You could use the current software for plan B.
    First, in the Impedance interface using the Adapter option select the needed resistor value, then select "W1-C1-DUT...". This will release the Supplies and DIO lines to be used from other interfaces, and the latching relays on the Adapter will remain unchanged. Then you can use the Static IO or Negative supply for other purposes, to control the external relay...

    image.thumb.png.ff57340d6a481b02b556bfdde95161ef.png

    Suggestion for improving the impedance analyzer

    in Test and Measurement

    Posted

    Hi @modmix

    I'm not sure if it is true but Windows Defender identifies it as threat!

    image.png.a645ffcbfbe2df21d9e312d89fab9fb6.png

    The AD1 and AD2 hardware are very similar. The API is identical. The only differences are in the power supplies configuration where AD2 voltages can be adjusted and user supplies vs auxiliary supply monitoring.
    The "Impedance Analyzer"/"Audio Analyzer Suite" software should work with AD2 if the creator would allow connecting to it. For this he only needs to accept the ID of AD2 like it does for AD1.

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