![]() ![]() The peak at 1 kHz at a level of 14.46 dBV correlates perfectly to what we saw on the scope. I have the analyzer set to display 10 Hz to 20 kHz, though Sony can easily reproduce audio signals to almost 100 kHz on the analog outputs. To see how this scale works, give my recent article on decibels a read. First, the vertical scale is in decibel volts. To make sense, I need to explain what you’re looking for on the analyzer for the rest of this article. Frequency-based analysis of the Sony XAV-9500ES playing a 1 kHz test tone. Let’s look at that same signal in the frequency domain using my QA402 audio analyzer. The image above shows the output of the Sony XAV-9500ES multimedia receiver playing a 1 kHz test tone at volume 50.Īs we advance, let’s focus on what’s happening with the AC waveform, since that’s what makes up audio signals and is crucial to our understanding of harmonic distortion. The measurement shown on the scope above is at a level of 5.28 volts RMS. In the example below, I’m playing a 1 kHz test tone on the impressive Sony XAV-9500ES multimedia receiver I reviewed in early 2022. The person making the measurement will set the scope to determine the speed at which the waveform is sampled (in milliseconds or microseconds per division) on the horizontal scale and the voltage per division on the vertical scale. ![]() Looking at an AC voltage on an oscilloscope, we can see the amplitude move up and down as the trace moves across the screen. The yellow trace in the image above represents the 14.44-volt output from my power supplies. If we look at a DC voltage, we see that the level remains constant as the trace scans across the screen. An oscilloscope measures and displays voltage over a period of time. If we take things a step further, we can look at these or similar signals using an oscilloscope. Here’s the 14.44-volt output voltage of my power supply bank measured on a multimeter. If we switch the meter to measure AC voltages and carefully poke the test leads into an electrical outlet in our home or office, we’ll see around 120 volts. If we set our multimeter to measure DC voltage and connect it to a car battery, we’ll see around 12.8 volts. A multimeter is a device that can measure DC or AC voltage, resistance and current flow. Let’s start with something much less confusing than an oscilloscope or audio analyzer – enter the multimeter. Let’s Start with Some Definitionsīefore we dive into distortion, we need to understand the difference between the frequency and time domains. It’s a complex subject and requires looking at signals in the frequency domain rather than the time domain. Several statements in the video and the comments made it clear that people don’t understand the concept of audio signal distortion. Last week a friend of mine sent a link to a YouTube video by Steve Meade, who was experimenting with line output converters using an oscilloscope and an SMD DD-1+ distortion analyzer. ![]()
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