Listen Technologies LA-140, Руководство по конструкции

Страница: 22 / 148

16
Design GuideDesign Guide
Design Guide
Designing a System
5A
Cross out the LT-82 transmitters not required in your system.
Cross out the LT-82 transmitters
5B
Determine how many radiators will be used on each radiator daisy chain by reviewing the room layout work-
sheet. Cross out the unused radiators on the system layout worksheet.
Determine how many radiators will be used
5C
Write in the coaxial RF cable lengths for each radiator used in the spaces provided. Review your room layout
worksheet for this information.
Write in the coaxial RF cable lengths for each radiator
5D
Draw a connecting line from the power supply output of the LT-82 transmitter(s) and the LA-205 power
VXSSOLHVWRHDFKRIWKHUDGLDWRUV.HHSLQPLQGWKDWHDFKWUDQVPLWWHUDQGSRZHUVXSSO\FDQSRZHUXSWRWZR
LA-140 radiators.
Draw a connecting line from the power supply output
5E
Cross out the unused power supplies.
Cross out the unused power supplies
5F
Write in the CAT-5 power supply cable lengths for each radiator used in the spaces provided. Review your
room layout worksheet for this information.
Write in the CAT-5 power supply cable lengths
5G
Now determine the delay compensation for each radiator using the Delay Compensation Calculator located
in the back of this design guide. The correct setting of the delay compensation is necessary only in systems
where there is overlap in coverage between two or more radiators. Write the delay setting on the System
/D\RXW:RUNVKHHW7KHGHOD\VHWWLQJIRUHDFKUDGLDWRULVGHWHUPLQHGXVLQJWKHFDOFXODWRUDQGDVIROORZV
Determine the delay compensation for each radiator
Determine which radiator is the furthest from the transmitter on one of the two daisy
chains. Calculate the distance from the furthest radiator to the transmitter and record it in
WKHÀUVWFROXPQRIWKHGHOD\FRPSHQVDWLRQFDOFXODWRU6HHH[DPSOHEHORZ
Distance of Furthest Radiator (DFR)
1
For each radiator, determine the overall distance from the transmitter to the radiator.
Record the value of each radiator in the RDT column. See example below.
Radiator Distance from Transmitter (RDT)
2
Determine and record the propagation delay of the coaxial cable being used. For Listen
coaxial cable the delay is 1.54 ns/ft or 5.05 ns/m. This information can be obtained from
WKHVSHFLÀFDWLRQVKHHWVVXSSOLHGE\WKHFDEOHPDQXIDFWXUHU
Cable Delay (CD)
3
Now calculate the delay setting for each radiator using the Delay Compensation
Calculator. The calculator uses the following formula to determine the delay setting of
HDFKUDGLDWRU
Calculate the delay setting for each radiator
4
Delay Setting = (DFR – RDT) x CD / 25
NOTE: If your calculations suggest a delay setting greater than nine, please
contact Listen Technologies tech support for more information.