21-10-2016, 04:23 PM
(This post was last modified: 21-10-2016, 04:24 PM by Murphyv310.)
Hi.
As there is already a thread about Franks pattern generator I'll give a review of the one Frank gave me to make up when I was discharged from hospital. The generator comprises a small board, it has three outputs, Composite Video, (75ohm) and separate frame & line syncs (50ohm)
I'll not go into the circuitry on this post as I am purely showing the results on a TV.
The original chip gave an out of 407 lines and the field frequency was correspondingly out, another small discrepancy was caused by some of the ceramic resonators being a bit off from 6Mhz. Frank has kindly supplied me with a new chip and a crystal conversion.
The results are good if not to the quality of the BBC test card "C", the circle is slightly ragged on the "test card option". The crosshatch, checkerboard, grey scale and other patterns are of good quality and extremely useful.
The other use this little generator is to supply syncs, I've already used the syncs to lock up the free running oscillators in my Pye lynx camera, having an interlaced picture makes a huge difference to the results.
I've taken some screen shots from my Philips Tvette using my phone so the white balance isn't too great and it doesn't do the generator justice.
I'll add more info to the thread in due course.
Cheers.
Trevor
MM0KJJ. Member of, RSGB, GQRP, WACRAL, K&LARC.
Trevor
MM0KJJ. Member of, RSGB, GQRP, WACRAL, K&LARC.