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42 Cards in this Set

  • Front
  • Back
(808) What is the original source of the continuous wave (CW) transmitter drive?
37-MHz crystal oscillator.
(808) The transmitted pulse is made of two .5-microsecond pulses, separated in frequency by...
37 MHz
(809) The stabilized master oscillator multiplies the continuous wave transmitter drive signal to...
(809) How long is the traveling wave tube (TWT) turned on to amplify the transmitted RF pulse?
1.35 usec
(809) The purpose of the traveling wave tube (TWT) radar modulator in the transmitter is to...
provide voltage amplification and trigger shaping for the TWT.
(809) In the AN/GPN-22 transmitter, which fault would cycle the transmitter to the STANDBY mode of operation?

a. Traveling wave tube (TWT) arc.
b. High voltage (HV) deck fault.
c. Standby converter fault.
d. Airflow fault.
a. Traveling wave tube (TWT) arc.
(810) The principle purpose of the antenna beam position unit (ABPCU) and array phase control unit (APCU) in the AN/GPN-22 is to...
generate phase delay commands to phase shifter elements of the antenna.
(810) The 443 memory constants for each beam position are sent to the phase computation algorithm and converted into phase commands containing how many bits?
(810) Which of the following is an off-line test preformed on the antenna position control unit?

a. Mode control
b. Open loop
c. Closed loop
d. Rebound Test
d. Rebound test
(811) The AN/GPN-22 precision approach radar's transmit/receive (T/R) section does what?
It prevents receiver damage by the transmitter high-power pulse during transmission.
(811) The best description of sensitivity time control (STC) attenuators is they...
automatically adjust receiver sensitivity in the discrete normalizing target return energy depending on range.
(811) The sensitivity timing control (STC) assures constant amplitude intermediate frequency (IF) signal to the receiver by...
providing high attenuation for near targets (which produce strong signals) and gradually less attenuation for distant targets.
(811) In the AN/GPN-22 precision approach radar, the total multiplication factor used by the stabilized oscillator (STALO) to achieve an X-band frequency is?
[808] Why is the TWT used in the AN/GPN-22 instead of a magnetron?
The TWT provides high amplification over a wide range of frequencies, which is something a magnetron cannot do.
[808] Describe how the TWT amplifies an RF signal.
The TWT amplives through the bunching of electrons in an electron stream interacting with the RF signal energy on a helix, with each causing amplification in the other.
[808] The STAMO is a frequency multiplier that multiplies the input VHF drive signal by what factor?
[808] Why use contiguous pulses?
To provide frequency diversity.
[809] How many transmitter(s) can radiate into the antenna at a time?
Only one at a time
[809] Which LED on the front panel of the low power transmitter monitors the input VHF signal?
[809] What determines the amount of RF drive applied to the TWT?
The setting of attenuator AT1
[809] What is the purpose of the TWT Modulator A6?
It is a pulse shaper and voltage amplifier. It contains a regulator and clamp circuit that produces a flat-topped output pulse that is used to turn on the TWT.
[809] Define a 3X fault.
A condition that may cause damage if it is allowed to persist or reoccur in rapid succession.
[809] If a standby fault occurs, the transmitter cycles to what mode?
OFF mode
[809] List the events that take place during a 3X fault.
First the HVPS shuts down temporarily, then a second time, then shuts down completely. The system must be reset manually. An indicator points out which fault caused the condition.
[810] Name the units that make up the antenna beam position control equipment and the location of each unit.
The Antenna Beam Position Control Unit (ABPCU) located in an equipment rack in the PAR shelter and the Array Phase Control Unit (APCU), located in the antenna assembly.
[810] State the principal function of the interface equipment.
To generate appropriate phase commands to each of 443 phase-shifter elements of the antenna.
[810] Where are the control signals and the antenna beam positoin commands from the TDC routed?
To interface control circuits and TDC command data register logic respectivly.
[810] In scan mode the beam can be directed into how many separate beam positions?
[810] What are the two methods for testing the ABPCU and APCU?
Off-line tests and On-line tests
[810] How can the inputs from the TDC be duplicated during the off-line testing?
By the use of the ABPCU front panel controls.
[810] Which off-line test analyzes the communication lines between the Antenna Beam Postion Control Unit (ABPCU) and the Antenna Phase Control Unit (APCU)?
Rebound Test
[810] What is the purpose of the Shift Register test?
It analyses each shift register and the associated parallel data input lines, and reveals faulty block decodes.
[811] What is the purpose of the high-power ferrite circulator 1A40A1A2HY1?
The duplexer directs the RF from the transmitter to the antenna horn for transmission and directs the received sum channel RF energy to the receiver sum channel.
[811] List the parts of a reciever-protector.
Pretransmitt/Receive, STC, and two diode RF attenuators
[811] What is the condition of the STC attenuators just before transmitter firing a radar pulse?
All attenuators are switched in to provide maximum attenuation.
[811] What channel contains the FET amplifier?
The sum channel
[811] What is the multiplication factor in the reciever front-end STALO?
[811] In what mode of operation does the sum channel FET amplifier get bypassed?
Track mode
[811] What is the purpose of the UHF preamplifier?
The UHF amplifier-mixer provides RF-to-IF conversion, low-noise amplification, and IF image rejection for the sum, azimuth difference, and elevation difference signals.
[811] What is the final result caused by the negative pretrigger pulse to the STC circuit located in the UHF preamplifier?
It switches in the IF attenuators.
[811] At what increments are the attenuators stepped down as range increases?
10 dB steps
[811] Where does the receiver frount-end BITE signal originate?
In the transmitter, a sample of the RF drive signal is picked off from the signal chain at a point proir to the TWT.