The EICO Model 368 TV“FM Sweep generator is to our knowledge
the finest and most highly perfected instrument of its type
available for factory and service alignment of tv and fm
receivers. The Model 368not only incorporates new features
which are unusual for instruments in the price range, but
provides more ranges and better performance than any
competitive make. The features are listed below.
• Entirely electronic sweep circuit (no moving parts, hum,
or vibration) using an increductor unit, in which the
oscillator coil inductance depends on the controllable
excitation current in the primary windings of the unit. The
increductor provides a large and smoothly variable sweep
width and the sweep obtained is extremely linear and stable.
There is also nothing to fatigue or wear out with use and
age. The availability of a large sweep width renders
operation of the instrument non-critical, since the
band-pass region is easily located on the scope trace even
when tv set or generator are considerably off frequency.
Once the band-pass waveform is located, it is only a matter
of adjusting the sweep generator center frequency, the
sweepwidth, and thephasingof the60cps sweep voltage fed to
the horizontal amplifier of the'scope to cause the pattern
to fill the desired section of the 'scope screen.
• Extremely flat RF output provided by newly-designed AGC
circuit which automatically adjusts the oscillator for
maximum output on each band with minimum amplitude
variations. Resonance - free RF choke eliminates “suck-out"
points anywhere in the RF spectrum. The AGC action
constitutes an electronic regulation of the output, not the
power supply (which would be undesirable).
• Extremely high RF output level on all five bands permits
the cold alignment of all tuned circuits and filters.
• Phased 60 cps sine sweep (fed to horizontal axis of
’scope) is obtained by bleeding and filtering a large
voltage from a secondary winding of the power transformer.
In this way, the 60 cps sweep voltage is both undistorted
and isolated from the line. The undistorted sine sweep
provides excellent linearityof frequency versus horizontal
displacement on the 'scope screen.
• Multiple marker system for easieralignment. A variable
frequency marker oscillators covers from 2 me to 75 me on
fundamentals in three ranges and from 60 me to 225 me on
harmonicsof highest fundamental range. (Note that the marker
range includes the color burst frequency of 3.58 me.) The
fixed marker is a crystal controlled oscillator employing a
4.5 me crystal supplied with the instrument. As the crystal
plugs into a panel mount, other crystals may easily be
substituted when desired. Fixed and variable osci I lators
have a common output, controlled by a fine attenuator, which
affects the markers only, and a coarse step attenuator,
which affects both the markers and the swept RF output. When
fixed and variable markers are mixed, pips appearon the
'scope trace at the fundamental and harmonic frequencies of
both and at the difference and sum frequencies. If the pips
so obtained are not close enough for a particular job, a
crystal of lower frequency can be used. The output to
another marker generator can be fed into an external marker
connector on the panel if the work requires a marker
frequency not covered by the internal variable oscillator.
The external marker can also be used to beat against the
internal fixed and variable markers to provide a third set
of marker pips. The output of the internal marker oscillator
can also be taken out of the external marker connector for
external use, if desired.
• Positive action return trace blanking.
• Double pi line isolation filter.
• Tuning dials protected by plexiglass windows. Edge- lit
hairline indicators provide exceptional tuning accuracy
because paral lax error is eliminated from settings. 6 : 1
vernier tuning mechanism for ease of fine adjustment.
• Advanced wiring techniques and heavy filtering e-
liminates hum and leakage.