There are some units on eBay, but the sellers mostly don’t know and describe them as having the “Opt 001” inside, a.k.a. 33120-80001, a.k.a. 33120-66503.
The Option 001 phase lock/TCXO timebase gives you the ability to generate synchronized phase-offset signals. An external clock input/output lets you synchronize with up to three other 33120As or with an external 10-MHz clock.
Please take note of the differences and do not sell with wrong description.
Last updated on 2022:12:20 at 01:24 UTC