Canon A-1 Repair Manual page 32

(2) Digital Control
The A-lis camera controls (input, memory, computation
and control) a r e all taken care of by digital signals.
Digital systems have following features compared to
the analog systems.
AS controls for the desired operations are carried out
by digital signals (combination of on-off switches)
instead of by analog values, there is no unfavorable
results from changes in temperature and humidity, no
wearing out of the parts sllch as resistors, and no
deterioration from age. This means upgrading of
quality and improved performance reliability.
The employment of the digital system instead of the
analog system results in lower manufacturing cost,
and more compact design. (Ver~atile functions due to
greater circuit density in the compact body.)
The infusion of solid-state technology for the display
of information resulted in improved durability against
vibration, shock and environmental change, and thus
greater reliability.
Great increase 1n the amount of information that can
be displayed and information that can be read with
far greater accuracy.
Reduction in the total number of parts and component
parts requiring adjustments. Quite a few parts can
be put into the form of monolithic IC chip and this
means lesser need to, as additional process, solder
parts such as resistors and capacitors. Credibility
in performance and cost reduction are thus realized.
Through digital control "of automatic exposure and
shutter speed, repeatability is improved . It means
greater overall accuracy.
Incidentally, in some aspects digital systems are
looked upon unfavorably compared to the analog system.
For example, digital response is not stepless. The
A-l's digital system is an 8-bit unit which means a
capability to control shutter speed and flstop values
in
1/8
step increments. (Yet in accuracy there is an
improvement over the previous analog control.) And
in readouts fresh information is fed every 0.5 second
and information display appears in 0.5 step increments.
This 0.5 value was established from the reasons of
easier viewing of displays and familiarity with the
values displayed. It is possible to display in-between
33