HP Agilent 33120A AWG Opt 001

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.

Without option
With option
Option itself

Symmetricom Rubidium Standard

This precious thing allows me to connect my GPSDO and have very stable 10MHz output, so all test equipment can use it as reference. The GPSDO itself provides very stable frequency, but has “only” an OCXO inside. So, long-time stability comes from GPS, but now short-time stablility also comes from the rubidium standard and not from the OCXO anymore. So more long- and short-time stability!

Actually this is a DOCSIS Timing Interface device. But, you can use it as 10MHz Rubidium Standard, because an X72 from Symmetricom is built in. There is also 10MHz reference input, which can be connected to GPSDO. So, the internal rubidium standard will be adjusted to the external 10MHz from GPSDO thus resulting in stable and clean 10MHz out of the rubidium oscillator.

And… having an atomic clock at home is really cool ;)

View 500MHz on Tektronix TDS380

This is how the old good Tektronix TDS380 acquires a 500MHz signal from Marconi Instruments 2031 signal generator. Very stable, calm trigger and display. No jumping around, albeit using 16x averaging.

And this is a picture of how 800MHz signal looks on the same scope.

And, last image is, the same setup, but a 1GHz signal, same scope.

Playing with the oscilloscope

This is frequency modulated signal on a oscilloscope, but the carrier frequency is lower than the modulation frequency.

In XY mode, two signals and all zoomed. Had much fun changing the frequencies and wave forms. Endlessly interesting patterns.

The special pattern you see has something to do with the oscilloscope’s internal 10kHz trigger frequency. But it’s just a guess. It could also be a ground loop problem.

Max freq of test equipment

Many measuring devices have a maximum frequency up to which they work correctly, as stated by the manufacturer. Above that frequency they don’t just stop working, rather they still have a range above where they still may work correctly, just aren’t as sensitive. Many oscilloscopes, for example, can work up to twice their bandwidth, but the measured amplitudes are not more than some random numbers. You can still see the waveform, but not do any meaningful measurements.

ManufacturerModelInputStated freqWorks freq
Agilent53181ACH1225 MHz400 MHz
CH23 GHzsure 2.7 GHz
Philips6654A120 MHz160 MHz
C1.5 GHz1.81 GHz
TektronixTDS380CH1400 MHz820 MHz
CH2400 MHz640 MHz
HamegHM1507-3CH1150 MHz250 MHz
CH2150 MHz260 MHz
HamegHM8021-2A1 GHz1.09 GHz
B150 MHz180 MHz
HamegHM8021-3A150 MHz240 MHz
C1 GHz1.47 GHz
HamegHM8021-3A150 MHz240 MHz
C1,6 GHzsure 2.7 GHz
HamegHM8021-4A150 MHz170 MHz
C1.6 GHzsure 2.7 GHz
Philips6611A80 MHz110 MHz
Oscilloscope: max triggered freq / Counter: max precise counted freq

Signal generator used: Marconi Instruments 2031.
Settings: output level +13dBm, frequency step 10MHz.