The microfiche reader-printer is a self-
To ensure a wide variety of whistle characteristics,
contained machine designed for reading and
the fundamental frequency of a whistle must be
printing enlarged copies of microfiche images.
between the following defined limits:
There are normally two modes of operation:
reading and printing. During the reading mode, an
250 to 700 Hz, for a ship less than 75 meters
enlargement of the microfiche image appears on
(240 feet) long
the translucent viewing screen. A print of the
image may be made by pressing a PRINT button on
130 to 350 Hz, for a ship 75 to 200 meters
the console of the machine. After an exposure and
(240 to 650 feet) long
development cycle, the print emerges from a slot in
70 to 200 Hz, for a ship more than 200
meters (650 feet) long
basically of six systems. These are the optical system,
light source, paper feed system, developing system,
paper cutter, and power distribution system. These
A whistle shall provide in the direction of
systems are all housed in a cabinet and frame
maximum whistle intensity and at a distance of 1
meter from the whistle, a sound pressure level in at
least one 1/3-octave band within the range of 180 to
OPTICAL AND LIGHT
700 Hz ( + 1 percent) as listed in table 11-1.
The purpose of the optical system is to project
an image in sharp focus on the viewing screen. This
is accomplished with a system of mirrors and lens.
according to the applicable technical manual. All
Figure 11-1 is an optical system from a 3-M 500
preventive maintenance should be accomplished
Reader-Printer. In this particular system, the
according to the preventive maintenance card for the
reflector is adjustable to allow concentration of the
system aboard the ship at the time.
The lamp is the source of the light rays.
Normally, the voltage of the lamp is adjustable. This
There are many types and sizes of microfiche
allows the operator to select the proper exposure for
equipment in use today. Regardless of size and shape,
the particular microfiche image.
they all accomplish the same job.
Table 11-1.--Intensity Level and Audibility Range