Gary Ayton's camping and photography wiki

see also:

• oscilloscopes

• https://www.fnirsi.com/products/dpos350p
• a great value for money budget Chinese battery powered combination 2 channel oscilloscope, signal generator, spectrum analyzer and frequency response analyzer with a 7“ touch screen
• but given the price as would be expected, there are some significant limitations which may not make it useful for many use cases, in particular:
  • at time periods longer than 20msec/div, it seems that it automatically engages rolling mode and you can no longer set a trigger value hence a trigger event only can capture a max of 0.2secs
    • this means you cannot capture the starter motor current as it compresses the pistons to assess relative compression pressures - you only get the initial crank current and its delay - there does not seem to be a way of turning off rolling mode and allowing trigger mode at these longer time periods
  • no ability to finely adjust vertical axis;
  • no rise time measurement;
  • cannot select specific probe settings other than from the 4 main configuration settings you can store
  • trace buffer limited to 60,000 samples
    • hence at 10msec/div which gives 0.1secs of capture, acquisition is 50000 per 0.1 sec (10 divs x 10msec = 0.1 sec capture) hence 500KSa/s is automatically used
    • and at 20msec/div which gives 0.2secs of capture, acquisition is 50000 per 0.2 sec (10 divs x 20msec = 0.2 sec capture) hence 250KSa/s is automatically used
  • no maths functions
  • no demodulation of signals - ie. no support for UART
    • high end scopes can be set to recognize the hex and even ASCII content of serial data and can even trigger from a given hex value - this scope cannot do any of that
  • the simple FFT display does not offer any measurements you have to guess the frequencies based on position in the grid
  • the signal generator has limited output to only 5V and other limitations
  • spectrum analyzer has limited resolution at ~29kHz
  • reviewers have stated there are some software issues with spectrum and frequency response analyzers
    • eg. frequency response analyzer log scale lines constantly show the same 3 decades of lines irrespective of selected range and thus are only accurate for some settings and needs some improvements to software
• https://www.aliexpress.com/item/1005008897925504.html ~$AU375

• timing chain / camshaft
• misfiring engine
• assessment of ignition coils, spark plugs
• assessment of CAN-BUS function

• component assessment
• circuitry

• 2hr 8000mAh 29.6Wh battery
• 18W QC 2hr fast charging - only comes with either EU or US AC 18W QC charger
• 10W 2.4A consumption;
• 7” 1024x600px touch screen;
• very fast boot up time of only 3 secs

• 2 channels with female BNC inputs with max 400V high-voltage input with overvoltage protection;
• “350Mhz bandwidth” limited by hardware to 150Mhz/50MHz;
  • when using 2 channel inputs, max is 150MHz per channel
• max 1GSa/sec;
• time base range / div = 5ns to 50sec
• roll time base is automatically activated and triggering disabled for time bases 50msec-50sec/div
• time accuracy +/- 0.01%
• DC accuracy +/- 2%
• adjustable vertical resolution from actual 8 bit and up to 16bit resolution although above 8 bits appears to be software interpolated
• 60000 pts buffer trace memory;
• basic trigger options
  • does not seem to allow triggering if time is longer than 20msec/div?
• X-Y mode
• vertical sensitivity at 1x probe: 2mV-20V sens;
• 1x/10x/100x probe setting;
• two 350MHz Probes with 1x/10x switches
• simple FFT display
  • does not display frequencies but you can guesstimate then from the position in the grid - each division changes with the Hor. time period
  • each division = 10000Hz/Horiz time division in msec
    • ie. if time period is 1msec then each division is 10kHz, if 10msec then each division is 1kHz
    • NB. you lose the FFT and channel measurements with time period is 50msec/div

• FFT length (resolution): 4K-32K;
• 200kHz-350MHz range
  • this covers radio frequencies of high end of LW, AM MW, SW, all of VHF (ie. including FM radio, Airband, digital TV, DaB digital radio, 6m and 2m Ham bands, and Aeronautical Radionavigation) as well as low end of UHF which may include some radar
  • can be extended to 0Hz to 500MHz but with attenuation, this may help detect ISM 433MHz and CB radio
  • the 200kHz lower limit is not going to show audible sound frequencies as these are much lower than this (the scope mode and FFT will display them though)
• Level range -60 dBmV ~ +260 dBmV
• waterfall;
• 3D waterfall chart;
• signal strength is in dBmV not dBM;
• limited resolution at ~29kHz at its max 32k FFT window and 950Mhz sampling
• https://www.youtube.com/watch?v=8onuyeiZuFY
• see also spectrum analyzers

• sine wave 0-50MHz;
• others up to 3/5/10MHz;
• max 5V;
• 50,000 wfms/s;
• Frequency resolution 1 Hz
• Amplitude resolution 1 mV
• Offset resolution 1 mV
• Duty cycle resolution 0.1%
• Customizable captured waveform 500 groups
• can output a captured wave form up to 3MHz;
• see also signal generators

• Excitation signal frequency 100 Hz ~ 50 MHz
• Excitation signal amplitude 0~5 VPP
• Excitation signal offset -2.5V ~ +2.5V
• Excitation frequency count 20~500
• Cursor measurement Frequency / gain / phase
• “very cool and useful” but:
  • the log scale lines constantly show the same 3 decades of lines irrespective of selected range and thus are only accurate for some settings and needs some improvements to software
  • no averaging of repeated assessments
• see https://www.youtube.com/watch?v=8onuyeiZuFY
• see also frequency response analyzers

• https://www.youtube.com/watch?v=kyA4d5DfWvY automotive use - assessing network BUS signals
• https://www.youtube.com/watch?v=gsuC_kD4kt0 automotive use - cam and crank sensor assessment and engine timing
• https://www.youtube.com/watch?v=Noav-EsKkug - automotive use
• https://www.youtube.com/watch?v=jdcUqWK2NGU review part 2
  • no ability to finely adjust vertical axis; no rise time measurement; only has sinx/x and no vectors;
• https://www.youtube.com/watch?v=8onuyeiZuFY review part 3
  • FFT function does not give any measurements so only good for qualitative viewing.
  • freq response analyzer worked well but could do with some averaging
  • “best value for money scope”
• https://www.youtube.com/watch?v=qMOetpIUgGQ review
  • Vpp seems to vary when zooming or setting Auto and ch2 gave 1-8-2.5 x the actual voltage if zoomed out but freq is accurate
  • no math functions
• https://www.youtube.com/watch?v=nILiuOlv9V8 review
  • will take up to 400MHz input although above 200MHz, amplitude becomes attenuated, however, when using 2 ch, max is 150MHz per ch and amplitude starts to drop over 175Mhz up to 230MHz
  • spectrum analyzer signal strength in dBmV appears to be incorrect and there are a lot of harmonics presumably from over-saturation of input and perhaps internal shielding issues; fairly high noise floor and lowish dynamic range; no peak search function; can't set a resolution bandwidth and seems quite poor;
  • freq resp analyzer: phase values don't seem to be correct
• https://www.youtube.com/watch?v=dcexJ4CTvOg - review
  • noisy cooling fan but the boot up time is only 3 secs so u can just turn it off when not in use
  • no multi-touch zoom but the 25% greater resolution than the Rigol makes a big difference
  • 12V 20W power via USB-C but adds lots of noise unless grounded
  • doesn't have a proper roll mode - ie. if you freeze it, you can't go backwards to review
  • great scope for the price although only has 60,000 trace buffer - Rigol has 6 million
  • spectrum analyzer has limited resolution at ~29kHz at its max 32k FFT window and 950Mhz sampling but can pick up FM radio stations just with a piece of wire, but not AM stations very well - much better than the Rigol but no where near as good as a SDR
  • freq resp analyzer is very cool and useful but the log scale lines constantly show the same 3 decades of lines irrespective of selected range and thus are only accurate for some settings and needs some improvements to software