Lab.gruppen D Series Operation Manual page 27

Trigger voltage
100
90
80
70
60
50
40
30
20
10
0
0 5 10
Frequency [kHz]
Fig 11.4: VHF Protection Frequency Sensitivity
The attack time of the VHF protection circuitry also changes with frequency, becoming shorter at higher
frequencies. This is shown in Figure 11.5.
Full output voltage
1400
1200
1000
800
600
400
20
200
0
0 5 10
Frequency [kHz]
Fig 11.5: VHF Protection Attack Time Variations
The VHF pr
continuous VHF content. HF content of normal music or speech signals at peak levels will be passed in full.
Operation of the VHF protection circuits is indicated by the channel's AMP LED that will illuminate yellow and
display VHF Warning when the max of -12 dB of gain reduction is applied (only applicable for D200, D120
and D80) and light red for a VHF FAULT. Both of these will be registered in the Lake Controller and CAFÉ
status views.
11.3.11. Short Circuit Protection
A low impedance or short circuit at the power output terminals is detected when the output current is high (Current
Peak Limiter is active) and, simultaneously, the peak output voltage is below a predetermined threshold. When this
situation occurs, the output stage is muted to protect it from damage.
Operation of the short circuit protection system is indicated by Amp channel LED showing steady red and a
corresponding text description will register in Lake Controller and CAFÉ software programs. Refer to Section 14.1
for more information on warnings and faults.
15 20 25 30
15 20 25 30
11. Operation and performance 11. Operation and performance
solely to detect
D SERIES Lake Operation Manual rev 3.0.4
D SERIES Lake Operation Manual rev 3.0.3
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