--- I had one left and I can't find it... Sorry.
I can build some more, but they'll be in the $1000 range for a short run. Size is 7-1/2" long X 3-1/2" wide X 2" deep for both the tramsmitter and the receiver, and the interface is a 50 pin "D" type connector with 50, 15" long test leads terminated in booted Mueller mini alligator clips which clip onto the cable under test.
Email me if you're interested for a firm quote.
-- John Fields Professional Circuit Designer
Just AND the clock with each of the output lines and you get 1-thru-32 pulses per cycle.
Then the receiving end can simply be a (probably BCD) counter and an LED or LCD display driver.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
"Winners never quit, quitters never win", Jack Bradley Budnik ~1956
Cute to drive the shield, PROVIDED they're not grounded somewhere.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
"Winners never quit, quitters never win", Jack Bradley Budnik ~1956
[snip]
Do it backwards? A chain of 32x 1k 1% resistors in series at the source-end, a cable inner connected to each tap, and all cable outers connected to the bottom end of the chain. Then use an ohmeter at the remote end to identify which cable.
1% of 32k is 320 ohms, plus (say) another 100 ohms for worst case cable resistance. 420 ohms is less than the 500 ohms resolution needed to identify which step.-- Tony Williams.
"Barry S." schreef in bericht news: snipped-for-privacy@4ax.com...
[snip]What about a box with resistors, of 1K, 2K, 3K, upto 32K. Then measure the resistance, using your multimeter.
-- Thanks, Frank. (remove \'q\' and \'.invalid\' when replying by email)
"Barry S." schreef in bericht news: snipped-for-privacy@4ax.com...
How would you connect 32 different frequencies to your cables? No matter what method you use, you still have to connect you cables...
-- Thanks, Frank. (remove \'q\' and \'.invalid\' when replying by email)
I think the main peeve against resistor strings in general is the ambiguity in readings in the case of wires shorted to each other. This doesn't apply to this request though; I think the OP is a cable company technician.
Jim Thompson wrote:
That was the main drawback of my original cut at this. That makes 32 ANDs or 8-quad ICs- so something had to be done about that. After fiddling with a few ideas it dawned on my that since this will a battery operated field instrument, you can chop all the output lines with a single gate driving the reference shield: View in a fixed-width font such as Courier.
. . XMTR . PWR LMTD . ISOLATED 32-bit SR . LINE # . ---------- . .--------|RST Q0|-------[1k]---> 32 . | | | . | | | . | '1'-|D Q1|-------[1k]---> 31 . | | | . _ _ | | | . _| |_| |_-------+--->CLK | . . | | | | . . 1KHz | | | | . . | | | | . | | | | . | | | | . | | | Q31|---+---[1k]---> 1 . | | ---------- | . | | | . | | | |\\ . | '---------------+--|---| o----> SHIELD . ------------------- __ | | |/ . | Q | / |----' | . | B |----< | | . | CD4538 | \\__|-------' . | | . ------------------- . 3ms ONE-SHOT . . . -------------- . | __ __ | . | | | | | | . | -- -- | . | | | | | | . RCVR | -- -- | . ------------- . | . / 14 . CD4093 | .LINE __ __ -------------------- . >-|>|-+--[33K]--+----| \\ | \\ | | . | | | o--| o-->CU CD40110 | . [3.3K] | .-|__/ |__/ | | . | | | | | . | | | | LATCH RST | . --- | | -------------------- . com | | _ _ | | . | | | | [100K] _|_ . | | | | . | | '--------. +---. . | | | | | .SHIELD | +------[100K]-------+----+-----||-' [10K] . >----. | | | | | 100p | . | | === | | | --- . | | | 470p | | | com . --- | --- | | | . com | com | | | . | __ ------------------- . | | \\ | Qa Bb /Qb | . +-----------| o---|Ba | . | |__/ | CD4538 | . === | | . 470p ------------------- . | 1,5ms retriggerable . --- . com . . .
Shield can be grounded anywhere- just keep it connected to RCVR COM and isolated from XMTR COM.
A microcontroller would do this easily in a single chip (plus power and caps if you want to ac couple).
Instead of straight tones you could send morse letters (a-z, 0-9 gives you 36 symbols without even having to use 2 digits).
You could also build a custom box on the other end to receive the signals. With a small pic and some big decoders you could bit-bang out something like I2C or SMB (round robining among all of the wires) and pick it up with a pic on the other end.
Hell, if it's coax cables you could probably bit-bang out enough NTSC to put up a couple of digits on each one. It's been done many times for one output and moderately high res (eg pong-like). Super low res but many output might not be that hard. Do the vertical blank and front/back porch stuff in parallel and then multiplex out the display. Maybe in binary with horiz stripes?
-- Ben Jackson http://www.ben.com/
New version with count-type outputs...
Simulation presumes a pull-down resistor on each output (*), otherwise the tri-stating will create "floats", which could make decoding difficult.
(*) Or on the receiver probe.
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |
Newest version with count-type outputs and extended blanking to make trivial receiver synchronization....
Simulation presumes a pull-down resistor on each output (*), otherwise the tri-stating will create "floats", which could make decoding difficult.
(*) Or on the receiver probe.
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |
That's much better...
In article , John Popelish wrote: [...]
You can do better if you allow more divider types and run the BRMs up at a higher frequency. It is a good idea to divide after the BRM to reduce the jitter in the output anyway.
-- -- kensmith@rahul.net forging knowledge
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