Peak/Slow/Fast Switch
This three position slide switch, labelled SLOW-FAST-PEAK,
determines the damping coefficient of the analogue meter. The
SLOW position sets the instrument for the standardised ‘slow’ meter
response with a time constant of 1 second. In the fast setting the in-
strument has a time constant of 125ms for the standardised fast meter
response. When the meter is used in the PEAK mode, the meter has
minimum damping and allows quick acting transient sounds to be
shown.
Maximum Hold Button
The MAX button is a momentarily acting push button which holds
the maximum sound level whilst the button is depressed. Once the
button is released the meter returns to normal operation. This facility
is very useful for capturing the maximum rms sound level of tran-
sient sound events.
Filter Mode Switch
The octave band filters can be used by placing the switch in either
the MAN or the AUTO position. When in the OUT position the me-
ter operates as a normal sound level meter with a ‘linear’ (‘flat’) or
‘A’ weighted response. When using the filters the ‘A’ weighted re-
sponse can also be used if desired.
The filters can be used in two different modes, MAN or AUTO. In
the MAN (or manual mode), the centre frequency of the filters is
changed by depressing either of the select buttons, ‘frequency up’ or
‘frequency down’. The frequency of the filter currently in operation
is displayed by means of ten LED’s (light emitting diodes) ,
positioned on the front panel.
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Summary of Contents for GA112
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