Atec Agilent-81133A-81134A - Manual (Page 2)

2
Connectors
Front panel connectors
All signal outputs and inputs are
accessible at the front panel.
These are:
• 2 (or 4) output connectors for the
1 (or 2) differential channel(s)
• Trigger output
• Clock input
• Start input
• 1 (or 2) delay control input(s) for the
1 (or 2) channel(s)
Rear panel connectors
Remote programming interfaces:
GPIB, LAN, USB 2.0 (see also
‘Additional Features’)
Clock Source
Selecting the clock source determines
the origin of the time base. All other
timing parameters are derived from it.
There are two choices:
Internal
The Clock is derived from the internal
oscillator.
External
The Clock is derived from the external
input. The ext. frequency is measured
once and is thereafter used to
maintain the calculated frequency
dependant values including the pulse
width or phase if set to duty cycle
mode or phase mode respectively.
External 10 MHz reference
A 10 MHz reference clock can be
applied to the clock input. This clock
is used as a reference for all timing
parameters.
Direct mode (direct internal/
direct external)
The direct modes allow changes of
frequency without dropouts in the
range of 1:2. This can be used for
applications, where dropouts would
make a measurement impossible
(e.g.: PLL frequency sweep, micro
processor clock sweep). In both direct
modes, the delay and deskew of all
channels is set to zero (deskewed at
the connectors) and can’t be changed.
Square mode, data mode (NRZ only)
and PRBS mode (NRZ only) are avail-
able. In ‘Direct External’ mode the
PLL is bypassed and the instrument
exactly follows the externally attached
frequency.
Frequency/Period
The main frequency is set for all chan-
nels. The frequency can also be set as
period length. The frequency range is
15 Hz to 3.35 GHz, equal to 66.6µ to
298.5 ps period. The frequency range
can also be further divided individually
for each channel.
Available dividers are 1, 2, 4, 8, 16, 32,
64, 128.
Main Modes
Pulse pattern mode
In Pulse Pattern mode, each chan-
nel can be set independently to one
of the channel modes described in
‘Channel Modes’.
Burst mode
Burst mode enables the output of a
burst consisting of data repeated n
times followed by continuous zero
data. It can be started either by:
• applying a signal at the start
input.
• the start button.
• sending a command through
the remote connections.
Repetitive burst mode
This command selects a repeated
burst consisting of data repeated n
times followed by a pause of p times
zeros of the same length as the data
before the data is repeated.