Here's a cable we made for our SecurityCamera2000 CMQ1993X FPV Camera (also works with the PZ0420). This cable powers the camera from a 3S LiPo battery, filters the power with a capacitor, diode, and ferrite choke, and sends signal and power to your OSD or Video Tx.
1. Batt power (red) to positive (no white stripe) side of diode.
2. Negative (white stripe) side of diode to Positive (no white stripe) side of capacitor.
2. Negative (white stripe) side of capacitor to Batt GND.
3. Camera power (red) to Positive side of capacitor.
4. Camera GND (black) to Negative side of capacitor.
5. Camera signal (yellow) to OSD or Video Tx.
6. GND (black) from Negative side of capacitor to OSD or Video Tx GND reference (important: this wire runs straight to the OSD or Video Tx; don't use a ground reference coming via some other indirect connection that will result in a corrupted video image).
The resulting circuit is the same as the power filter for the camera in the project described here: http://www.rcmodelreviews.com/fpvbackpack02.shtml
And in the schematic at http://www.rcmodelreviews.com/filestore/Schematic.pdf, the upper left hand portion is this exact same circuit, with the capacitor and diode filtering the power for the camera.