2001 Wohler Technologies, Inc. ALL rights reserved
1
I. GENERAL
DESCRIPTION
The AM-2B is a CRT based display system used to verify proper stereo audio phase,
amplitude and separation.
The oscilloscope display shows the phase relationship between the left and right channels.
Channel 1, or left, drives the scope Y-axis and channel 2, or right, drives the X-axis. The
correct phase vector is marked on the graticule with a line and the words "IN PHASE" for
operator convenience.
Measurement of amplitude is done with average reading true VU meters and peak reading
LED meters. The VU meters, one each for left and right audio, meet all electrical and
ballistic specifications established by Bell Laboratories and ANSI as required by broadcast
and sound engineers. The LED peak reading meters, one each for left and right audio, are
full wave rectified, reading both positive and negative peaks. They have a rise time response
of approximately 250 microseconds and a fall time of 300 milliseconds.
Audio inputs are through 3-pin XLR connectors and are balanced and buffered with greater
than 50K ohm input impedance. Inputs can be resistively terminated according to studio
standards.
