Modulation Keys - HP 8340B Operating Instructions Manual

Modulation Keys
DESCRIPTION
These three keys select frequency modulation, pulse modulation, or amplitude modulation of the RF
output. These keys are used in conjunction with the front panel FM, PULSE, and AM BNC connectors
(shown in Figure 3-15). Table 1-1 lists instrument specifications for the three types of modulation.
PANEL LAYOUT
mam
modulation ■■■
o o o
' FM
j
' PULSE
j ^
AM
j
FUNCTIONS
rPULSEl (HP-IB: PM1 turns on pulse modulation. PMO turns off the function) activates the pulse
modulation function. When pulse modulation is in effect, the RF output of the HP 8340B/41B is turned
on (full power selected) and off (>80 dB attenuation) at a rate determined by the pulse modulation
input (described in Figure 3-15). Pulse and amplitude modulation can be in effect simultaneously
(amplitude modulation is described in a following paragraph). Press [PULSE] a second time to turn off
the function.
rSHIFT] [PULSE] (HP-IB: SHPM) turns on pulse modulation, allowing proper operation with HP
8755C 8756A, and 8757A scalar network analyzer. The scalar analyzers' 27.8 Khz square wave
modulation output is connected to the HP 8340B/41B PULSE input. When the SHIFT PULSE mode is
activated, the RF output of the HP 8340B/41B is modulated by the 27.8 kHz square wave. This
capability is present on all HP 8340B/41B's regardless of option configuration. Pressing [PULSE] (HP-
IB: PMO) will turn off this function. This mode may be used for other purposes, providing 2 nsec rise
and fall times for pulse widths wider than about 7us.
TAM] (HP-IB- AMI turns on amplitude modulation, AMO turns off the function) activates the ampli-
tude modulation function. Amplitude modulation allows the pre-attentuated RF output of the HP
8340B/41B to be continuously and linearly varied between —30 dBm and the maximum power avail¬
able, at a rate determined by the AM input (described in Figure 3-15). Amplitude and pulse modulation
can be in effect simultaneously. Press [AM] a second time to turn off the function.
TFM1 (HP-IB- FM1 turns on frequency modulation, FMO turns off modulation) activates the frequency
modulation function. Frequency deviation is dependent on the magnitude of the input signal. Pressing
rpMl a second time turns off the function. FM sensitivity is either 1 MHz/volt or 10 MHz/volt and is
selected by following the FM1 "on" sequence with either [1] [MHz] or [1] [0] [Mhz] respecitvely.
[SHIFT] [FM] has no effect on the HP 8340B/41B.
Figure 3-14. Modulation Keys
HP 8340B/41B
Operating Information