05-08-2012, 11:55 AM
I owe Al a visit so perhaps we should descend on him and beat it into submission 
Many moons ago I had a Solartron 'scope, long gone, which used valve dividers for the Calibrator. It consisted of a series of Blocking Oscillators which free ran just below the required frequency. Each stage was driven from the previous stage via a Diode Pump if I remember rightly. The threshold was set so that the tenth input pulse triggered the stage. There was a pot to set the threshold. It was a bit delicate.
I also have here two TV Pattern Generators which use similar transistor dividers to Al's, so I guess the technique was fairly general in that era, although I don't remember ever using it myself. I'll have a look at the Circuits to see if there's any sense to them.
Alan
Many moons ago I had a Solartron 'scope, long gone, which used valve dividers for the Calibrator. It consisted of a series of Blocking Oscillators which free ran just below the required frequency. Each stage was driven from the previous stage via a Diode Pump if I remember rightly. The threshold was set so that the tenth input pulse triggered the stage. There was a pot to set the threshold. It was a bit delicate.
I also have here two TV Pattern Generators which use similar transistor dividers to Al's, so I guess the technique was fairly general in that era, although I don't remember ever using it myself. I'll have a look at the Circuits to see if there's any sense to them.
Alan
