4.1 Measurements for Dynamic Characteristics4.2 Playback Performance
PC Playingtestdataatf =44.1kHzbyapplicationsoftware
(forexample,SoundRecorder,MediaPlayer,etc.)
S
USB
Connector
D2 D1
SW1 JP1
J1
JP2
J2
100mA
0dB
PCM2912A
PCM2912A-EVM
Mic
Headphone
AudioPrecision
SYS-2722
AnalogAnalyzer
Leftch
Rightch
RL
Measurements for Dynamic Characteristics
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Typical dynamic performance graphs for playback and recording devices generally represent threeperformance characteristics (in addition to other specifications): total harmonic distortion and noise(THD+N); signal-to-noise ratio (SNR); and dynamic range (DR). For playback devices, channel separationis also a performance characteristic. These graphs also specify the test environment and measurementconditions required in order to meet typical performance values defined in the product data sheet.
For the DEM-PCM2912A EVM, the evaluation environment specifications are:
•Equipment used: Audio Precision, System Two Cascade Plus
•Power supply: V
BUS
= 5.0 V (Bus power setting)
•Temperature: Room/ambient
The DEM-PCM2912A EVM performance presented in this section was obtained under the followingconditions:
•f
S
= 44.1 kHz
•Output PGA (Speaker output volume): 0 dB
•Sidetone from microphone PGA: –76 dB (mute)
•R
L
= 10 k Ω/ 32 Ω/ 16 Ωare inserted into headphone jack J2 for headphone output
•Jumper setting: set JP1 to 100 mA and JP2 to 0 dB
•Application software for playback: Sound Recorder, Media Player and ITunes for Windows Vista/XP;QuickTime and ITunes for Mac OS X.
•Equipment: AP2 Analog Analyzer (SYS-2722)
Configure the equipment as shown in Figure 4-1 .
Figure 4-1. DEM-PCM2912A EVM Configuration for Playback Performance Measurement
34 Evaluation and Measurements SBAU141 – January 2009Submit Documentation Feedback