1-24. TEST CONSOLE TEST BENCH 2A2 (cont)
(b) Command, flag, and timing signals from the digital computer assembly
1A1O control the transfer of camera signals to the bus multiplexer CCA 2A2A7A6A7.
(9) Bus Multiplexer CCA 2A2A7A6A7.
The bus multiplexer CCA operates in different
modes to process data between the digital computer assembly and the multiprogrammer
assembly, analog to digital converter assembly, and FIFO memory.
(10) Programmable Pulse Generator (PPG).
The PPG logic CCA, PPG mux CCA, and PPG
analog CCA provide digital pulses for the video signal generator and UUTs. Twelve
connectors on the front of electronics drawer assembly route signals from the PPG CCAs
EXTENDER ASSEMBLY 2A2A8
The extender assembly receives and transmits serial data to the
HP-1B extender 1A9A1 in the electronic station.
(2) Receive Mode
(a) A data frame arrives as a string
the data passes through and is synchronized
of 22 bits at the receive coupler where
with an internal clock frequency of
The rear panel SERIAL DATA RATE switch is set to NORMAL.
(b) From the receive coupler, the data frame is clocked into the decoder.
After decoding, it is clocked into the 16-bit data register.
Then the four parity
bits, start bit, stop bit, and frame reject signal are checked, and if correct the 16
data bits are loaded into the parallel register.
Transfer from the 16-bit data
register to the parallel register is the serial-to-parallel conversion.
(c) Data is transferred to the bus interface, status is checked, the hand-
shake sequence between extenders is performed, and the data frame is put onto the
IEEE 488 bus.
(3) Transmit Mode.
After the receive data frame has been accepted and the hand-
shake sequence completed, the HP-IB extender assembles a return frame. The return
frame is passed to the 16-bit data register, clocked into the encoder, encoded into a
transmit data frame, and transmitted over coaxial cable by the transmit driver.
MATRIX SWITCH ASSEMBLY 2A2A1O
The matrix switch assembly 2A2A1O (FO-28) is remotely controlled to
enable external instruments in the AN/USM-410 test station to access units under test
Control of the matrix switch assembly is from the switch controller assembly
2A2A12, operating under computer control via the IEEE 488 bus.