Texas Instruments DEM-PCM2912A EVM manual Recording Performance, Dout

Recording Performance www.ti.com

4.3Recording Performance

The DEM-PCM2912A EVM playback performance presented in this section was obtained under the following conditions:

∙fS = 44.1 kHz

∙Input PGA (Microphone input volume): 0 dB

∙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.

∙Use analog input data provided by the AP2 analog generator (SYS-2722) with unbalanced floating ground setting.

Configure the equipment as shown in Figure 4-2.

PC

Recording￿at￿fS =￿44.1￿kHz￿by￿application￿software (for￿example,￿Sound￿Recorder,￿QuickTime,￿etc.)

			Mic
			J1
	PCM2912A
			Headphone
D2	D1	100￿mA
USB	SW1	JP1	J2
		0￿dB
Connector
		JP2
	PCM2912A-EVM

Audio￿Precision

SYS-2722

Analog￿Generator

Unbalanced

Floating￿GND￿setting

Figure 4-2. DEM-PCM2912A EVM Configuration for Recording Performance Measurement when

Recording Data

To measure recording performance with the recording data, use S/PDIF digital interface output data. Connect the EVM to the AP2 digital analyzer (SYS-2722); for example, as the DEM-PCM2704 EVM shown in Figure 4-3.

PC

Volume￿gain￿=￿0￿dB

USB

Connector

DEM-PCM2704EVM

S/PDIF

Output

Audio￿Precision

SYS-2722

Digital￿Analyzer

Figure 4-3. DEM-PCM2704EVM Configuration for Recording Performance Measurement with Recorded

Data

Table 4-4. Line Input Recording Performance

Power Supply	Performance	Filter Setting	DOUT
5.0 V	THD+N (–1 dB at 1 kHz)	400 Hz to 20 kHz LP	0.008%
	SNR (BPZ input)	400 Hz to 20 kHz LP	92.5 dB
		+ A-weighting
	DR (–60 dB input)	400 Hz to 20 kHz LP	90.5 dB
		+ A-weighting

36	Evaluation and Measurements	SBAU141–January 2009
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