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10-09-2018, 03:50 AM
Oscilloscopes for audio - Part-3
The OWON XDS2102A is bigger in person than the photos suggest and the 8" screen is divided into 10 vertical divisions by 16 horizontal (1cm graticule with further subdivision by ten). The unit is about 2.6kg (5.72-lbs) and feels hefty. One nice thing about a DSO is that since it is a piece of industrial equipment that is designed to measure tiny high-frequency signals, it must be fully shielded. This means its own noise-generating CPU and other circuitry cannot spray EMI into the environment. You can get the unit with a North American mains plug or a European one. I bought mine from Hilitand Instruments Store on Aliexpress.
The OWON showed up some issues with my signal generator inasmuch as the generator output is a little drifty until it has been running for quite a while. It's over twenty years old and has a frequency counter as well. The counter's two least-significant digits fluctuate constantly, reflecting either the counter's inaccuracy, the generator's instability, or both. The scope can lock the waveform on its own depending on how you set its triggering, or if you set it to catch the wave in memory.
With a music signal or guitar input, the DSO does show a small delay in its response which I was expecting. It is large enough that you could find it annoying or not? For most tests we do with the oscilloscope we are using continuous signals and the small latency is a non-issue. For example, when the generator was still drifting, the wave on the scope display would be stable but a ghost wave would appear every few seconds or so. This is very "analog-y" and you can even get the scope to show a doubled wave -an inverted wave over the noninverted wave - just as if it were a CRT scope with the trigger not set properly - you won't feel like you're missing analogue for very long - haha.
Generally, the DSO will lock the wave form right away. You can have aspects of the wave displayed, such as the peak value, RMS value, or its period (time for one cycle). There are usually "zoom" functions, as well, where you can set cursors vertically and/or horizontally and then see that part of the wave expanded in an alternate view. This is where the memory depth and vertical resolution work together to show fine detail. You should have a look at the videos on OWON's site.
One thing that the XDS2102A excels at, as I'm sure most DSO do, is showing high-frequency noise. For example, switch-mode power supplies operate at high-frequencies and produce noise output at much higher frequencies. Things get worse if secondary SMPS modules are powered from the first and "beat" frequencies are created that get into the grounds and power paths. These noise pulses feed right through any post-regulator circuitry there might be and intermodulate with the audio signal. The result is an increase in general noise - hiss - but with a an "edge". Where a regular scope may not show this, the DSO does.
The OWON XDS2102A is bigger in person than the photos suggest and the 8" screen is divided into 10 vertical divisions by 16 horizontal (1cm graticule with further subdivision by ten). The unit is about 2.6kg (5.72-lbs) and feels hefty. One nice thing about a DSO is that since it is a piece of industrial equipment that is designed to measure tiny high-frequency signals, it must be fully shielded. This means its own noise-generating CPU and other circuitry cannot spray EMI into the environment. You can get the unit with a North American mains plug or a European one. I bought mine from Hilitand Instruments Store on Aliexpress.
The OWON showed up some issues with my signal generator inasmuch as the generator output is a little drifty until it has been running for quite a while. It's over twenty years old and has a frequency counter as well. The counter's two least-significant digits fluctuate constantly, reflecting either the counter's inaccuracy, the generator's instability, or both. The scope can lock the waveform on its own depending on how you set its triggering, or if you set it to catch the wave in memory.
With a music signal or guitar input, the DSO does show a small delay in its response which I was expecting. It is large enough that you could find it annoying or not? For most tests we do with the oscilloscope we are using continuous signals and the small latency is a non-issue. For example, when the generator was still drifting, the wave on the scope display would be stable but a ghost wave would appear every few seconds or so. This is very "analog-y" and you can even get the scope to show a doubled wave -an inverted wave over the noninverted wave - just as if it were a CRT scope with the trigger not set properly - you won't feel like you're missing analogue for very long - haha.
Generally, the DSO will lock the wave form right away. You can have aspects of the wave displayed, such as the peak value, RMS value, or its period (time for one cycle). There are usually "zoom" functions, as well, where you can set cursors vertically and/or horizontally and then see that part of the wave expanded in an alternate view. This is where the memory depth and vertical resolution work together to show fine detail. You should have a look at the videos on OWON's site.
One thing that the XDS2102A excels at, as I'm sure most DSO do, is showing high-frequency noise. For example, switch-mode power supplies operate at high-frequencies and produce noise output at much higher frequencies. Things get worse if secondary SMPS modules are powered from the first and "beat" frequencies are created that get into the grounds and power paths. These noise pulses feed right through any post-regulator circuitry there might be and intermodulate with the audio signal. The result is an increase in general noise - hiss - but with a an "edge". Where a regular scope may not show this, the DSO does.
