Pim Puls .XR 7

[kadir6141]

drawing
There are some missing places.

[kadir6141]

thank you orbit. one best orbit

[Ferric Toes]

Original Pimdec and Superdec Parts List

I took this with a camera. It is reasonably clear when zoomed in.

Eric.

[kadir6141]

Thank you eric. Part list.

[bernte_one]

[ATTACH]42110[/ATTACH] drawing
There are some missing places.

delete all ultra long trace under ic sockets, just use some trace on top layer (or wire bridges instead)

if you upload sprint layout file as rar or zip Container i can Show you how

[kadir6141]

Yet not fnished

[eclipse]

Here's v0.4 with some component value fixes - XR7.pdf

[Ferric Toes]

Things move fast on this forum. I bet Orbit did not reckon that the response to his initial post would be on its 3rd page within a week.

It would be interesting to hear comments about what the seemingly complicated stages in the receive path do, and what the advantages (if any) are there over more conventional analogue circuitry.

Eric.

[Orbit]

Things move fast on this forum. I bet Orbit did not reckon that the response to his initial post would be on its 3rd page within a week.

It would be interesting to hear comments about what the seemingly complicated stages in the receive path do, and what the advantages (if any) are there over more conventional analogue circuitry.

Eric.

Hi Eric I am simply thrilled I can not wait to arrive pcb for small plaque to finally return everything its original state !
The guys are drawing fast am also delighted .

[Altra]

It would be interesting to hear comments about what the seemingly complicated stages in the receive path do, and what the advantages (if any) are there over more conventional analogue circuitry.

Eric.

I do not see any form of a dc to dc converter which is typical in PI's. From the original schematic it appears only one set of batteries is used with single +/- connections. IC3 LM741 looks like a virtual ground to form "-VT". Maybe the differential transistor pairs in the receiver are to level shift the signal to be within the common mode range of the LM318? Also do not see a damping resistor? Maybe off board or built into the coil?

TR4 and TR9 are interesting. Some type of blanking or SAT?

Nice to recover this kind of information before it's lost forever.

[KingJL]

IC3 LM741 looks like a virtual ground to form "-VT".

Correct (creates -VT on Eric's schematic).

Also do not see a damping resistor? Maybe off board or built into the coil?

Seems that R5 (Eric's schematic) is doing some damping above the diode thresholds.

[green]

Correct (creates -VT on Eric's schematic).


Seems that R5 (Eric's schematic) is doing some damping above the diode thresholds.

I use the input resistor, R5(Eric's schematic) for the damping resistor for my mono coil amplifier. Wondering if the circuit needs another damping resistor.

[Ferric Toes]

I use the input resistor, R5(Eric's schematic) for the damping resistor for my mono coil amplifier. Wondering if the circuit needs another damping resistor.

I wonder what happens when the flyback voltage drops below 0.6V. Is there an overshoot or ringing? It is something that is easily tried or simulated. Perhaps it did not matter as the first sample delay was relatively long in these detectors.

Eric.

[green]

I wonder what happens when the flyback voltage drops below 0.6V. Is there an overshoot or ringing? It is something that is easily tried or simulated. Perhaps it did not matter as the first sample delay was relatively long in these detectors.

Eric.

Spice simulation where input resistor is damping resistor.

[KingJL]

LtSpice model of Superdec Front end

This is a LtSpice model of the superdec front end. The collector circuit of Q7 (TR4 of Eric's superdec schematic) is tied back to the negative rail as the timing logic is not modeled. It appears that the FE gain is about 122.

Schematic:


Frequency response:



LtSpice Files:
superdec_FE.zip