Broadcast Electronics 3000 Series - Azimuth; Stereo Phasing Test

5-41. AZIMUTH
Playback head azimuth is adjusted while reproducing a 15 kHz tone
from the alignment cartridge. Record head azimuth is adjusted while
recording a
15 kHz tone from an external signal generator at a level of -10
VU on the front panel meter. Adjust the azimuth screw for peak 15 kHz output
as
measured on an external VU meter. Remove and reinsert the cartridge
several times and repeat the adjustment.
5-42.
STEREO PHASING TEST
Once the azimuth and height are established as described in
paragraphs 5-41
and 5-42, check the unit's phase response. Connect the
right and left playback outputs to an oscilloscope as shown in Figure 14.
Reproducing the alignment
test cartridge (playback units) or recording from
an external signal generator connected to both inputs (record units), observe
the
Lissijous pattern produced on the oscilloscope. Alternately check the
phase response
at 400 Hz and at 4,000 Hz tone can easily be phased 360
degrees rather than 0 degrees, so check the 400Hz tone after adjusting the
azimuth
(4,000 Hz tone).
Remove and reinsert the cartridge and perform the phasing test
several times.
OSCILLOSCOPE
VERT.
HORIZ.
RIGHT ________________________ -J
OUTPUT
LISSAJOUS PATTERNS ADJUST
HORIZONTAL AND VERTICAL FOR EQUAL SENSITIVITY
Figure 5-2. Tracking Cartridge and Stereo Phasing Test
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