Open micbeldyga opened 3 months ago
So to summarize, there should be the following connectors:
The switch can be replaced by a DIP switch and available only from inside; make x2 x3 x4 options available.
Adding x2 option complicates things. Since each Sel0, Sel1 and Sel2 inputs is 'tri-level', i.e. it can discriminate between 0, Vcc/2 and Vcc, I'd place a ON-OFF-ON slide switch on each SelX pin and add a key/graphic on the silk screen with x2/x3/x4 settings marked
Great. I assume that adding LEDs on the panel gets complicated? Maybe some LMV339 would do the job..
Right, now driving LEDs becomes really a crux of the project. Avoiding erroneous LED states may get tricky. Have to look into it
Let's do the opposite. Just make a 3-way switch, 3 LEDs, and a set of MOSFETs to control pull-up, pull-down, and Hi-Z states.
If you feel that it's overengineering, leave the x3/x4 option using the internal DPDT switch. We already have x2 output
by saying "we already have x2 output" I meant that we can use first bank of divider and set division to 1. That would require adding a dip swich.
by saying "we already have x2 output" I meant that we can use first bank of divider and set division to 1. That would require adding a dip swich.
Should x1/x2 option be available on any particular connector or should we have it as an option for the entire "Bank1", i.e. LEMO, 2x SMA and SFP?
Since there are outputs available in Bank2 and Bank3, we can rearrange the connections and have x1/x2 option available only for a specific connector.
Lemo and SFP will always be 40MHz; connect it to bank 1 SMAs scan be 40, 80 MHz, connect them to bank 2 Two other SMAs can be 80, 120, 160 MHz; we will drive Kaslis with them. Connect the multiplier to bank 3 That will cover all use cases However, if we can make it more versatile without complicating things much, let's do it. For unused LVPECL outputs it's fine to install just pulldown, no need to dissipate power with proper Thevenin termination
left to right: USB-C power input 40MHz clock via SFP 40MHZ clock via LEMO connector 120/160MHz via 2x SMA, frequency selected with internal switch. Selection indicated with front panel LED 40/80MHz via 2x SMA, frequency selected with internal switch. Selection indicated with front panel LED
First draft of front panel connectors placement.
From left to right:
SMA staggered with 10.5mm spacing like in DIO_SMA project
It's a tight squeeze, especially around switch and LED indicator. Since SMAs shouldn't be placed any tighter, additional room must be found by moving LEMO, SFP and USB-C connectors