Texas Instruments DEM-PCM2912A EVM Datenbogen
4.1
Measurements for Dynamic Characteristics
4.2
Playback Performance
PC
Playing test data at f = 44.1 kHz by application software
(for example, Sound Recorder, Media Player, etc.)
(for example, Sound Recorder, Media Player, etc.)
S
USB
Connector
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
R
L
Measurements for Dynamic Characteristics
www.ti.com
Typical dynamic performance graphs for playback and recording devices generally represent three
performance 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 separation
is also a performance characteristic. These graphs also specify the test environment and measurement
conditions required in order to meet typical performance values defined in the product data sheet.
performance 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 separation
is also a performance characteristic. These graphs also specify the test environment and measurement
conditions 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 following
conditions:
conditions:
•
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
Ω
are 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.
QuickTime and ITunes for Mac OS X.
•
Equipment: AP2 Analog Analyzer (SYS-2722)
Configure the equipment as shown in
Figure 4-1. DEM-PCM2912A EVM Configuration for Playback Performance Measurement
34
Evaluation and Measurements
SBAU141 – January 2009