[time-nuts] ACAM GP22 Chip

[Robert LaJeunesse]

If the goal is to create two signals consistently spaced near 70us apart why not use a good, fast 8-bit serial-in, parallel out shift register, clocked cleanly at 100kHz? Using the outputs from stages 1 and 8 would result in a 70us delay between signals. The data in would be fed 100KHz divided by 10 (or 16, or anything greater than 8) at whatever duty cycle is available. This allows the GP22 to see the combined instabilities of the clock and the shift register, which could be down in the nanosecond range, possibly less since the shift register delays would inherently cancel all but their differences.

Bob LaJeunesse

> Sent: Tuesday, November 24, 2015 at 9:04 AM
> From: "Thomas Allgeier" <th.allgeier at gmail.com>
> To: time-nuts at febo.com
> Subject: [time-nuts] ACAM GP22 Chip
>
> Hello,
> 
> I have an ACAM GP22 TDC chip and evaluation board which I am looking at for “work” purposes – I work for a company active in the weighing and force measurement world. 

...

> We want to use this chip to measure the period of a square wave, of around 13 kHz i.e. in the 70 µs range. As the application is potentially high-accuracy we need to know the period to within 1 ns or better.