The AS3340 example circuit uses a higher pulse out pulldown, and the onboard zener is a bit different so you can use a slightly lower Vee series resistor, but it works just fine with the CEM3340 values.
The sync inputs expect brief spikes, and the example schematics just use 1 nF capacitors on the way in, to turn pulses into spikes:
EDIT: The 1222 performance VCO follows the example schematics, and routes the sync input via a 1 nF capacitor (C4).
EDIT: I just noticed that the CEM3340 data sheet has a section on sync on page 6, with a couple of alternative sync circuits, and some discussion about voltages.