Theory UQN"
OR "MASTERn PU LSES -
E.G"
lIF
SWITCH SIGNAL FROM CAMERA
-1--\-~\~-\-~\~-\--\--I:--l~-
"OFF" OR "SLAVE" PULSES fI fI fI FLIP/FLOP
aNn
[1d SYNC METER
fI
SPROCKET
HOLES
/\
/\
/\
~
I
,
U U
I I
OFF
FROM MAGNETIC FILM
rn
~
n n
tEXTRA "ONu
PULSE
~
[1d
METER SWI NGS
RAPIDLY ACROSS .6.T THIS POINT
In the i1 1 ustr~tion shown. the Cdmera is assumed to be ru nni ng faster than the Super 8 Sound Recorder. Master pulses are coming ear l ie r and earlier in each cycle relative to the s lave pulses from the sprocket holes. This s low speed "error" in the Super 8 Sound Recorder is detected and measured by a digita l 10g1c device known as a "flip/flop". EaCh master puls e turns t he flip/flop to its "on" state , and each sl ave pulse turns the flip/ flop "off" . If the recorder is slow, as assume<!, the nerage time the flip/flop is on will be increasing. The d~erage "on" t i me of this fli p/flop is an error SigMl which can be fed back 1nto the mo tor of the Super 8 Sound Recorde r, creating a closed se r vo " l oop", with the following property of stability at t he correct master pulse rate: If the Reco r der runs slow relative to the master sync pu ls es. the average voltage from the flip/flop inc r eases, speeding t he Recorder up to the correct speed.
IF the Reco rder runs fast relative to the master sync pulses, the average voltage from the flip/flop decreases, slowi ng t he Recorder down to th e co rrect speed.
EACH PIC TURE FRAME TURNS THE FLIP/FLOP NON " I
FLIP/FLOP LOGIC CIRCUIT
EACH MAGNETIC FILM SPROCKET HOLE TURNS THE FLIP/FLOP "OFF" METER READS AVERAGE VOLTAGE
..../
6 _e_
WHEN NEEDLE IS STEADY , RECORDER IS LOCKED IN SYNC
AVE RAGE VOLTAGE FROM THE FLIP/F LOP IS FILTERED AND SUPPLIED TO THE RECORDER'S MOTOR