Tektronix RSA3300A, Service Manual

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Theory of Operation
RSA3303A & RSA3308A Service Manual
3- 5
The A30 Trigger board is an optional circuit board to achieve real-time frequen-
cy trigger function. The board consists of a dual port SRAM and a pipeline-con-
nected operational processor.
When the Frequency Mask Trigger function is activated, window function
operation is executed to the input signal first. To accelerate the operation, data
are divided into two groups: the odd frame data and the even frame data. With
pipeline-connected FFT processors, real-time FFT is applied to these groups of
data. After being converted into frequency domain, the data are further converted
into the power domain with a pipeline-connected quadrature-to-polar coordinates
converter. After comparison with the reference data, the trigger board outputs the
trigger detect signal. When the Power Trigger function is activated, window
function operation and FFT operation mentioned above are bypassed. The data of
the time domain are converted into the power domain and sent to Trigger
Comparator.
The A40 Memory board saves time domain data separated into I and Q signals
by the A20 DDC board. The A40 Memory board also interfaces between the data
block and Windows system.
I/Q data output from the A20 DDC board is saved to the dual port SRAM, and
then transferred to SDRAM as a block of data. The memory block of SDRAM is
also connected to the PCI bus via a different dual port SRAM. This allows the
Windows system to refer to the contents copied to this dual port SRAM as the
data on the PCI memory space. The TRIG IN and OUT connectors located on
the rear panel are connected with this board. The trigger detect signal output
from the A20 or the A30 board is output to an external device after being
synchronized with the memory’s address controller on this board. An external
trigger signal input is used, in addition, as the timing reference signal for the
address controller.
This memory board also contains a microprocessor that controls various software
settings and various types of hardware as well as peripheral devices such as
ROM/RAM.
Power Supply
The power supply circuit consists of two units of AC/DC Converter (Power
Supply 1 and 2) energized from AC power line, and A70 DC power board,
which regulates the output voltages of AC/DC converter units and distributes the
regulated outputs to each of the boards and fans.
Note that Power Supply 1 and 2 units have different output voltage specifica-
tions. The Power Supply 1 output voltages are +5 V / +15 V / --15 V / +24 V; the
Power Supply 2 output voltages are +5 V / +12 V / --12 V / +3.3 V.
A30 Trigger Board
(Optional)
S/N below B020000 and
J300100 and above
A40 Memory Board
S/N below B020000 and
J300100 and above
Power Supply 1 and 2