Specifications
11
The 8257C can modulate the RF car-
rier with four types of analog modu-
lation: amplitude, frequency, phase,
and pulse.
AM, FM, and
ΦΦ
M Sources
•AM, FM, and ΦM have two source
paths each. These multiple source
paths are summed internally for
composite modulation of the RF out-
put.
•Each path can be fed by one of four
sources: Internal 1, Internal 2,
External 1 or External 2.
•Only one path can be active for each
source. For example, if AM Path 1 is
on and AM Path 1 source is set to
Internal 1, if AM Path 2 is on, AM
Path 2 source must be set to
Internal 2, External 1 or External 2.
Different paths cannot use the same
source at the same time.
•Waveforms available from Internal 1
and Internal 2 include:
Sine
sine wave with adjustable amplitude
and frequency
Dual-Sine
dual sine waves with individually
adjustable frequencies and a per-
cent-of- peak-amplitude setting for
the second tone (available from
function generator 1 only)
Swept-Sine
a swept sine wave with adjustable
start and stop frequencies, sweep
time, and sweep trigger settings
(available from function generator 1
only)
Triangle
triangle wave with adjustable ampli-
tude and frequency
Ramp
ramp with adjustable amplitude and
frequency
Square
square wave with adjustable ampli-
tude and frequency
Noise
noise, in a uniform or Gaussian dis-
tribution, with adjustable amplitude
generated as a peak-to-peak value
(RMS value is approximately 80% of
the displayed value)
DC
direct current with adjustable ampli-
tude
Pulse Sources
The following list summarizes the
different sources available for pulse
modulation.
External Pulse
modulates an external pulse signal
connected to the signal generator’s
PULSE/TRIGGER GATE INPUT con-
nector.
Internal Doublet
produces two pulses at the RF OUT-
PUT connector for each trigger event
at the TRIGGER IN connector. The
first pulse will follow the external
trigger signal. The second pulse will
have user-defined delay and width
parameters.
Internal Free-Run
produces internal, free-run, pulse
modulation with user-defined peri-
od, width, and delay.
Part 2: Configuring Analog Modulation
(E8257C Only)
Internal Gated
produces an internal, gated, pulse
modulation. When a valid gate signal
is applied to the TRIGGER IN con-
nector, a pulse train (with user-
defined width and pulse repetition
frequency parameters) will occur at
the RF OUTPUT connector.
Internal Trigger
produces an internal, triggered,
pulse modulation. An RF pulse (with
user-defined width and delay param-
eters) will occur at the RF OUTPUT
connector whenever a valid trigger
signal occurs at the TRIGGER IN
connector.
Internal Square
produces internal, square, pulse
modulation. The internal source is a
sinewave which is later squared by
the modulator to generate the pulse
squarewave with a duty cycle set to
50 percent.
Internal Pulse
produces internal, rectangular, pulse
modulation with with user-defined
width and period parameters.