This instrument has been designed for production lines
and research on wide band amplifiers such as those
used in television and frequency modulation receivers.
Its outstanding performance is due to the incorporation
of original ideas specially adapted to this new technique.
In particular the range 5 - 220 Mc/s is covered on
a single scale without switching. All I.F. stages
can therefore be aligned, whatever may be their working
frequencies, and so can R.F. and local oscillator
stages up to and including 220 Mc/s.
This very wide frequency range is obtained by using
the difference in frequency between two oscillators
,one being swept about a fixed frequency and the other
being unmodulated but variable. Both frequencies are
always higher than 220 Mc/s.
A great advantage of this system is that only the
wanted frequency can act on the circuit under test,
all other frequencies being higher.This result is
not possible if the sum of the internal oscillator
frequencies is used.
Other features are:
Frequency sweeping is obtained by a system of variable
permeability. Neither mechanical parts nor electronic
tubes are used, this leading to stability and linearity.
The high attenuable output allows the use of any
oscilloscope provided with a horizontal amplifier,
even if the oscilloscope is not very sensitive or
the receiver out of alignment.