20
pointer advances and stays for a
sufficient time in order for
a reading to be taken.
The modulometer measures
signals that can affect systems
prone to overloading such as
amplifiers and radio transmitters.
It shows signal peaks that would
saturate - an average value of
the signal is of little value in
preventing system overload.
In particular, while monitoring
spikes, indications from the
modulometer are always exact,
no matter how long the duration
of the spike may be.
• VU Meter
On the contrary versus the
modulometer, the VU meter has
the same rise and fall time. It
indicates the accurate
physiological sound level with a
good balance between speech
and music. It is used a lot in
sound post-production houses.
It’s not at all adapted for the PL-
P.
Modulometer Calibration and its Use
There are 3 scales and 1 legend
printed on the face of the
instrument:
• Logarithmic-scale markings in
relative dB from –20 dB to +3 dB
indicating the output level
present at the tape loop output
connectors.
•
Linear-scale markings in
absolute voltage from 0 to 1.4 V
corresponding to the –20 dB to
+3 dB scale referenced to 1.0 V
at the tape loop output
connectors.
•
Linear-scale markings in
absolute voltage indicating
battery reserve per cell from 0.9
V to 1.5 V, with proper operating
voltage ranges marked in green.
• A written legend, “ref 0 dB = 1.0
V”, printed on the lower center
portion of the dial on the
instrument, reminds the user that
all modulometer markings are
referenced to 0 dB = 1.0 V on the
tape loop connectors.
The modulometer can be used to
aid in the following operations:
• Adjusting the Line A, Line B and
Line C internal level-matching
trim pots.
• Selecting moving-coil phono or
moving-magnet phono input with
internal jumpers.
• Selecting to bypass the moving-
coil phono transformer.
•
Adjusting the input level
potentiometer to reach:
