3L5

The Tektronix 3L5 is a 50 Hz — 1 MHz spectrum analyzer plug-in for 560-series scopes.

It is very similar to the 1L5 and can be used to measure the spectrum of signals. In conjunction with the 015-0107-00 "Swept Frequency Generator" (tracking generator), the 3L5 can also be used to make scalar frequency response measurements. A video filter switch was added to the later SNs (1971 Catalog).

75 Ω Version

There is also a 75 Ω version of the 3L5. Its input is on the rear, via a coaxial connector. A lever on the front panel switches between two frequency ranges:

10 kHz - 1 MHz
18.010 MHz - 19 MHz

Timebase Support

3L5 requires a timebase plug-in in the horizontal compartment to operate. Timebase plug-in units with serial no listed and below require modification 040-0413-00 to provide the sweep signal to the 3L5 (To pin 18 of the plug-in connector).