APx555 B Series & ADC Test Mode Option
AP’s second-generation APx audio analyzers—the B Series—are led by the APx555-B, which offers improved sine generator frequency stability, lower system residual distortion, single-ended, balanced analog output and an optional ADC test mode which provides VBias, a common mode DC Bias.
The B Series APx555 audio analyzer brings several enhancements to the analog high-performance sine generator that will have broad appeal to developers of high-performance audio devices such as compressors, limiters, amplifiers, codecs and digital signal processors. This enhanced analog generator (EAG)—standard with B Series APx555 analyzers and available as an upgrade for Legacy APx555 systems—provides several improvements in its low distortion sine generator and high-precision sine analyzer, including improved sine generator frequency stability with an accuracy of <30 ppm. The system can now also generate low-distortion analog sine burst signals from 5 Hz to 100 kHz and allows users to independently invert the signal polarity of balanced channel outputs. Finally, the B Series APx555 has lower system residual distortion, with THD+N improvement above 50 kHz (−2 dB) and THD improvement above 5 kHz (varying from −2 to −5 dB).
For design engineers validating and testing complex, multichannel analog-to-digital converters (ADCs), the B Series APx555 now offers an ADC Test Mode option capable of generating balanced analog audio signals mixed with a calibrated common mode DC offset voltage. This optional feature is especially useful in testing devices that operate on a single supply voltage and require inputs with a DC bias voltage, such as audio codecs and ADC chips in mobile products. The ADC Test Mode also includes programmable voltage limits to prevent overvoltage damage to the device being tested. This option is included when a Legacy APx555 analyzer receives an EAG upgrade.
It is worth noting that all B Series APx analyzers require APx500 audio measurement software version 5.0 (or later) but are compatible with APx project files created from version 4.6 (or earlier) software. APx500 software v5.0 requires Windows 10, or Windows 8, 64-bit operating systems.
For further information on the ADC Test Mode option, check out Technote 136: Measuring Low-Power ADCs with the APx555 ADC Test Option, which includes example APx500 project files.