what are at least three units that can be displayed by the power meeter?
Watts, Milli-watts, Micro-watts, Nano-watts, dB, and dB (REL)
how do you use the relative power measurement mode for frequency response testing?
You set the dB(REF) for the transmitter under test, and then monitor and changes in power at different frequencies or settings.
In general terms, what does a power sensor do?
Changes energy from one form into another form.
what are some of the older power sensors?
bolometers, calorimeters, thermistors, and thermocouples.
what are some of the advantages of a diode detector over a thermistor mount?
higher sensitivity, reduces noise, less frequency drift, and lower SWR.
How much more efficient is a detecting diode than a thermistor?
what device determines the power measurement range of a power meter?
The power sensor.
what must you do before you can use the power meter/power sensor system?
Marry (calibrate) them together.
why should you not twist a power sensor when installing it?
You may cause major damage to the power sensor's internal circuits.
What is the basic RF power measurement?
what must you do before turning ON the power meter?
Make sure it's set to match the line voltage you're using.
after you've turned the power meter on, what's the first task you must do?
Zero the power sensor.
How much RF input is allowed when zeroing the power sensor?
What happens when you press he dB (REF) switch a second time?
Enters a new reference level.
When taking measurements of a signal, should you make the signal as high and wide as possible, or as short and narrow as possible?
As high and wide as possible
At what percentage amplitude points do you measure the rise time of a pulse?
between the 10% and 90% amplitude points on the leading edge of the pulse.
How much faster should the vertical system of your scope be than the rise time of the applied signal?
2-5 times faster
what is the formula for converting time to frequency?
F = 1/T
What is the frequency range of the typical spectrum analyzer?
9kHz to 26.5GHz
What must be done to the spectrum analyzer before making measurements?
it must be calibrated.
What piece of test equipment is used to self-calibrate RF devices within system or test station?
Generally speaking, what does a counter do?
It accumulates, from an applied signal, input pulses in binary form, and then converts them to decimal form for a digital readout
what are the basic measurement functions of the universal counter?
frequency, period, time, totalize, and volts
what the most accurate, convenient, and flexible instruments available for making frequency and time interval measurement
electronic frequency counters.
what are the five operating modes of the pulse generator?
Normal, Trigger, Gate, External width, and External burst
what determines the number of pulses output in B.BUR mode?
by parameter values set by the range/vernier rocker switch.
ow many control modes can be selected?
What sweeper keys are used to select specific frequent and power levels?
what key selects the special functions
what frequency must the start frequency be, in comparison with the stop frequency?
Must be 100MHz lower
what does the CF key select
Selects the center frequency
what does the (Delta)F key select?
Frequency span for the center frequency.
What are the three basic requirements of facility power?
be at proper voltage, at the required amperage, and at the necessary frequencies
what is the input voltage requirements of a test station?
what are the input frequency requirements of a test station?
60Hz and 400Hz
what two components are required to produce voltage outputs from an AC power supply?
transformers and filters
DC power supplies use what three types of rectifiers?
1. Half-wave 2. Full-wave 3. Bridge
what is the purpose of the 400Hz power to a test station
provide all voltages for a TRU and LRU
what is a stimulus
anything thats generated for application to a TRU or UUT
what items are considered stimulus
Cooling air, AC voltage, DC voltage, RF signals, AF signals, Logic signals
what are the possible output signals of a waveform generator?
sine wave, triangular wave, square wave, DC voltage level.
what is the frequency range of an AF generator?
20-20,000 cycles per second
what is the purpose of a measurement device
measurement, monitor, or evaluate responses from a UUT
what type of signals do digital multimeter measure
AC voltage, DC voltage, and resistance
what is frequency counter period measurement
the time from one input pulse or signal to the next - measured in seconds
what is used to measure the power level of RF signals
what is considered the most versatile measurement instrument capable of a visual disply
what primary function does switching provide
a means of interconnecting test station resources with the UUT
test station switching has what two classifications?
stimulus and measurement
what are the three major considerations in designing proper switching in a test station?
1. selection of stimulus 2. routing of signals throughout the test station and to the UUT 3. Routing of UUT responses to a selected measurement device
what controls the switching in a computerized test station
program execution of specific test statements
what is considered to be the mostimportant test station function
what is a major factor in determining the type of control device a test station will have?
speed of the UUT operation
what is a computer program
a set of instructions that allow a digital computer to process data.
instruction identified by a code number describes what type of computer program
what is commonly used to represent the digits in computer language?
volts and current
IEEE-488: how many devices may be connected to one bus
up to 15
list the four catergories in which the IEEE-488 bus lines are grouped.
Data lines, handshake lines, Bus management lines, ground lines,
list three handshake lines
DAV, NRDF, NDAC
which handshake lines is asserted by a listener to indicate it is not yet ready for the next data or control byte?
list the five bus management lines
attention, end of identity, interface clear, remote enable, service request
describe a service request line
the SRQ is like an interrupt; it may be asserted by any device. the SRQ is released when polled by the controller.
when can the NDAC handshake line go high?
when the slowest listener has accepted the data byte.
what is multiplexing
the process of transmitting information from several sources through one system with different signals staggered in time to form composite pulse train
what is the biggest advantage of multiplexing
saving in size and weight of avionics units and the interconnecting wiring between them
how many types of avionic terminals are there, and list them
three. Buss controller, monitor, remote terminal
what is the purpose of the bus controller?
coordinating the flow of information on the data bus
what is the purpose of an RT on an avionics data bus?
any terminal not acting as the bus controller or bus monitor
what are the four elements making up the MIL-STD-1553 data bus system?
bus controller, bus monitor, remote terminal, the data bus itself
what does the bus controller do when it detects an error
ertransmit the command to recover from the error
an RT must be able to handle protocol errors. what's a protocol error?
incoming command and data that's electronically correct, but the message is illegal by the protocol established within the MIL-STD-1553
what element of the data bus is ca[able of assuming the task of bus controller in the event the bus controller fails?
a remote terminal
what element of a data bus is not needed for normal operation and is not normally included in avionic data bus systems?
what element of a data bus id not needed for normal operation and is not normally included in avionic data bus systems?
when are transformers-coupled stubs used in the 1553 data bus
when stub length is over 20ft long
which type of stub coupling is better, transformer-coupled or directed-coupled
what types of digital information or words are used on a data bus
command, status, and data
describe the common structure of command, data and data words
each word type is 20 bit-periods in length. each word has a command sync charter, which is three bit-periods in length, followed by 16 information bits and, finally, 1 parity bit
in the SAM feield of a command work, to what does "subadderss" refer
to a function or an area within the RT to which the command is being directed.
which elements of the data bus transmit data words?
bus controller or an RT
During a controller-to-RT transfer, what does the RT do after receiving command and data words form the bus controller?
the receiving RT validates the incoming command and data words. If the message is valid, the RT responds with a status word, acknowledging receipt of the command and data.
In an RT-to-RT transfer, what does the receiving RT do upon completion of the transfer?
once the receiving remote terminal has received and validated the data words, it responds with its own status word indicating that successful completion of the transfer
in mode command without a data word, what does the word count field contain?
mode code for the command to be implemented
for what does the abbreviation VXI stand?
VME extension for instrumentation
what factors largely drove industry to develop the VXI standard?
industry demand for reduction in physical size, tighter time and synchronization between multiple instruments, and faster transfer rates
List four benefits that VXI brings to instrumentation user.
1. open, multi vendor standards that maximize flexibility and minimize obsolescence 2. increase system throughput reduces test time and/or increases capability 3. more precise timing and synchronization improve measurements capability 4. modular, rugged design improves reliability, increases MTBF, and decreases MTTR
how can the logical address of a VXI device be set?
manually or automatically
what are the two classifications of VXI devices with respect to register capabilities
register based and message based
what are VXI message-based devices required to use in order to communicate in a standard way?
word serial protocol
what is defined by the VXI bus and used to construct a hierarchical system of VXI devices?
command-servant communication protocol
how does a message-based device communicate with it's commander
word serial protocol
how does a register-based device communicate with its commander
device-specific register manipulation
the VXI bus specifies how many modules?
what are the larger size modules (C and D) for?
high performance instruments
within the VXI mainframe, what provides the communication path between the other modules in the mainframe and the host computer
a VXI controller may contain an embedded computer and/or with what can it communicate?
what are the three methods used to control a VXI system?
1. VXI mainframe linked to an external controller via the GPIB 2. VXI-based embedded computer 3. A high-speed MXI bus link from an external computer.
how does the MXI bus interconnect devices?
flexible cabling scheme
what classifies a device as an MXI device?
with MXI interface board installed
how does the MXI bus tightly couple multiple devices?
mapping together portions of their individual address space
How do MXI devices directly access each other's resources
performing simple read and writes to appropriate locations
at what rate does does MXI bus data transfer?
8,16,and 32 bit
what is the maximum data transfer rate for the MXI bus?
describe the MXI bus point-to-point cable
has a single connector on each end
Describe a multidrop cable
sing connector on one end and two connectors on the other end
an MXI bus cable is similar to what other type of cable
The MXI bus requires the first and last devices in a daisy chain to have what?
Describe block data rate.
the rate at which you can move a large block of data to or from memory on an ideal VXI device using back-to-back VXI transfers.
what affects the actual data transfer rate that cab be achieved?
the read/write access time of your remote system and length of MXI cable
Why are system procedures to be used only by programmers who have intimate knowledge of the test station hardware, control system, and software system?
improper usage may cause improper connection, catastrophic damage to the test station, damage to the UUT, incorrect or ambiguous test results, incorrect resources status information
how d ATLAS system procedures allow low-level control of the test hardware?
by permitting direct output of hardware control signals on the station internal control buses.
a standard ATLAS program structure consists of what?
preamble and procedural structure
what is always the first section of an ATLAS program?
list the three functional classes of ATLAS statements that are commonly used in the preamble structure to define the words and phrases of the language?
common, declare, and define
how are ATLAS variables identified
By a label or name using single quotes, or dinks
what ATLAS statement number normally begins the procedural section and is normally the first executed statement during UUT testing?
in statement syntax, how is the provision for one-time looking back distinguished
by the dot on the bypass line
name six fields that can make up each ATLAS statement
Flag field, statement number, verb, field separator, variable, and statement terminator
what are the two basic fields in an ATLAS statement?
Fixed and variable
what does the variable field element of an ATLAS statement accomplish?
allows the programmer to specify in great detail exactly what is applied or how the timing of a signal is set up.
what are the types of statements that you don't need the rest of the test station to properly execute
which statments are used to set aside computer memory to hold the contents of variables
what do calculate/compare statements do?
test and modify the values of variable and system flags
COMPARE statements set or reset which system flags
GO, NO-GO, HI, and LO
What is the purpose of decision/branching statements
to alter the normal sequence of program flow.
How does a WHILE-END WHILE statements differ from a FOR-END FOR
the looping in the WHILE statement continues until the condition specified is satisfied
what function do test statements perform
they cause the test station hardware to perform specific tasks
what are the three categories of test statements
analog measurements, analog stimulus, and digital testing
For what are analog stimulus statements used
to make the test station generate a signal that is analog in nature
what are the six basic verbs used in a digital testing.
SETUP,CLOSE, READ, REMOVE, DO, and APPLY
what is the major difference between ATLAS statements and protocol?
The protocol doesn't have to be converted to machine code like on ATLAS statement does before the computer runs it
is substitute equipment allowed to be used to perform a PATEC calibration
Yes, provided they meet required functions, ranges and accuracies
What controls the automatic station calibration
What does the SECAL program control in the ATE computer during calibration
support equipment operation during calibration
what are the three main parts of the uncertainty factor
1. gross errors 2. system errors 3. random errors
list three types of systematic errors
Instrumental, Environmental, and Observational
which type of systematic errors result from external conditions, such as temperature, vibration, and magnetic fields
if a meter has been calibrated by PMEL and has a calibration sticker on it, where should you be about to trace the calibration standard to?
what ration ensures traceability
can you use a meter with an accuracy of .03% to align a meter with a tolerance of .02%
what calibration sticker is normally used to indicate ATE has been calibrated?
AFTO form 108
What does the SPECIAL block of AFTO form 99 identify
limitations placed on the piece of TMDE
when is AFTO form 256used on a piece of equipment
when an item is identified as needing no calibration
why must the PATEC remain plugged in to an acceptable power source
to maintain the Rubidium frequency timing standard
what happens if the PATEC is unplugged from its primary power source
its battery back up maintains calibration standard for a limited period of time
What is PYM-1 CAPRE system
a common reprogramming device that can be utilized by many systems on many airframes
what power source(s) is/are available to the CAPRE
AC adapter and an internal, rechargeable battery
what operating system runs the CAPRE computer?
What is the purpose of the CCM
convert files from the SFF to whatever format is required to communicate and transfer data
what DOD network may be used to transfer classified data
how often does the CAPRE rewuire visual inspection?