AP - The Recognized Standard In Audio Test

Class D amplifiers, switching power supplies, and D/A converters all produce spurious signals well outside of the 100 kHz bandwidth limit of most audio analyzers. These out-of band switching spikes, along with their harmonics and intermodulation products, can wreak havoc on audio gear and adjacent equipment. Audio signals combined with this noise can cause even more problems.

Ultra-high bandwidth analysis in the 100 kHz to 1 MHz band lets you identify and correct these problems. The APx BW52 ultra-high bandwidth option provides an unprecedented level of clarity with full 1 MHz bandwidth, 24-bit dynamic range and 2.38 Hz bin width at maximum FFT length.

The BW52 option is supported on the APx525 family and will be available January 2010.

Why 1 MHz bandwidth?

Why 24-bit resolution?

Square wave analysis with the AG52

Why 1 MHz bandwidth?

The switching frequency of Class D amps, sigma-delta converters and other modern audio devices often center around 250-300 kHz. Noise that is reflected into the audible range will directly degrade the sound.

Noise that remains above the audible range can also degrade the sound by causing problems such as oscillation, overheating and damage to components, loss of headroom, and interference with connected or adjacent equipment. A 1 MHz FFT is required to see the harmonics of this out-of-band noise.

Why 24-bit resolution ?

The higher the resolution, the greater the level of detail that can be seen above the noise floor. A typical spectrum analyzer may have very wide bandwidth (i.e: able to go far beyond 1 MHz) but the resolution is likely to be 8-bit, meaning many key details of the signal are totally obscured by noise. For example, 24-bit resolution allows low-level out-of-band artifacts to be seen clearly even in the presence of a much stronger fundamental.

 

Square wave analysis with the AG52

BW52's 2.5 MS/s sampling frequency allows APx to characterize square wave rise-times with unprecedented precision.

When BW52 is used in conjunction with the AG52 high performance analog generator option (which generates near perfect square waves), power amp designers have the best analyzer in the world for testing overshoot, undershoot, and ringing in the device under test.