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Application guide 78, Analog input gain structure examples – Lab.gruppen PLM 20K44 User Manual

Page 78

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10. Application Guide

78

PLM+ SERIES Operation Manual rev 1.0.0

Figure 10.3 illustrates how to achieve the lowest possible output noise, although this is not a recommended
configuration.

• Input Clip: 0 dBFS
• Amp Gain: 22 dB
• SNR: 114.8 dB
• Absolute Noise Floor: -71.9 dBu

Table 10.3: Digital Input Optimized for Minimum Noise - Not Recommended

The improvement in noise performance (at the cost of losing headroom and compression features) is only 0.6 dB;
it is therefore not recommended to optimize performance in this manner.

10.4.3.2. Analog Input Gain Structure Examples

Figure 10.4 illustrates how to minimize absolute noise while limiting the available SPL. Input Clip: 12 dBu

• Amp Gain: 22 dB
• SNR: 105.5 dB
• Absolute Noise Floor: -71.5 dBu
• SPL is limited to -8.9 dB relative to clip in this minimum absolute noise level example

Table 10.4: Analog: Low Noise with Limited Output (Low Input / Low SPL)

-250,0

-200,0

-150,0

-100,0

-50,0

0,0

50,0

100,0

Analog

AES Input

Input Mixer

Module In

Module Out

Amp

Attenuation

Analog Ref

Amp Gain

ISVPL

Output

dB

/d

B

u

Clip
Nominal
Noise

-140,0

-120,0

-100,0

-80,0

-60,0

-40,0

-20,0

0,0

20,0

40,0

60,0

Analog

AES Input

Input Mixer

Module In

Module Out

Amp

Attenuation

Analog Ref

Amp Gain

ISVPL

Output

dB

/d

B

u

Clip
Nominal
Noise

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