PI CHIP

[ashkelon]

hello
when reading 10 bit sample unisurfv3 output for example 500, in short time this number going down 490 - 480 .... there is no movement coil, battery voltage and current decrease so must adjust gain pot to find 500 again , working not stable. what can i do for this battery current variable problem ?

[PICoil]

I am trying to develop similar ckt using PIC16F1508 , i will be using its in build NCO and a pulse my TX coil , i am not sure about the analogue front end . Is there a IC with everything included that would derive a TX coil ?

[scrungy_doolittle]

fet switch

R36 forms a low pass filter to control the gate voltage on the damping mosfet. We are using the mosfet as a variable resistor here not a pulse driver. Any noise on this will modulate the damping and cause false target noises.


moodz

and yes, I understand that this is an old thread.
I first saw this done on a Russian medical instrument, circa 1985. Most creative abuse of a part ever. Using an opto in that case, and driving it with a variable duty pulse stream to generate damping. Gave no end of fits, so we went with a array of fet swiches to dampen the flyback. 7 damping levels. Used in an electrotherapy device.
Cheers

[starmoml]

Does this chip can be used to surf pi?
Schematic and hex file to give me. PLEASE

[sido]

Hi all,

Moods is the winning book still on offer on who can work out your GB method which is Trivial and should be known as you say???
No one has worked it out so far....correct??

You mention conventional RF Amateur principles used for years for a Antenna/RF power transfer Transmatch.....
We know thath C and R introduces alot of internal noise/heat intereference...so

I must have missed your post awhile back....since reading it now I have a suggestion for what it's worth.......

Does it have something to do with a Broadband Toroidal RF Choke/Balun???...tuned within the TX/RX frequency range of the Detector's operation??

This will have to depend on the (R) Resistance of the input RX amp and TX's overall (R) resistance to have a optimal transfer of TX power v's variable Coil RX.

To clarify me......Is it correct to say that there is No MCU Control of your GB method.....Is it purely physics and generic RF principles that you refer too in some previous post.

You have me thinking of how you go about your Simple Ground Balance that you have adopted which you say is trivial and should be known to all in RF System Concepts.

Do I win the Book prize....Heehhheee

Cheers Sid.

[hdphilip]

I am out in the field at the moment testing

A few nuggets for your attorneys will keep them happy....


Philip

[moodz]

I am out in the field at the moment testing ....however to answer your question there are two op amps configured for non inverting feeding into inverting both set to gain =10 or gain =33 providing a cascade gain of 100 or1000. ( ie 10x10 or 33x33 ). 22pf caps across feedback resistors.
...33x33 =1089 ..... But I still call it 1000 ;-)

[sido]

10 MHz. ... You can change the clock divider inside the chip. I have used the THAT device and ne5534 with equal success. I just coonected one side of the diff to ground and the other to signal. Could have done it better I suppose but have been caught up with front end business. :-)

Hi Moodz...are you using the NE5534 as a dual stage (low gain then higher gain).....and if so do you have the schema that you may want to disclose and share.

Interesting that both devices have same results!!...seeing that the THAT has better premium spec's for a differential input v's output than the NE5534.

Cheers Sid

[moodz]

10 MHz. ... You can change the clock divider inside the chip. I have used the THAT device and ne5534 with equal success. I just coonected one side of the diff to ground and the other to signal. Could have done it better I suppose but have been caught up with front end business. :-)

moodz,

on your MCP3903, what freq is the xtal? and are you usuing a differential op amp driver configured as a single ended to differential conversion for the adc frontend?

I'm planning on trying it on my qed project.

but in the meanwhile, I'm putting together a few circuits on a pcb to send to the pcb fab house as a "test" board, and i'm including a circuit for the mcp3901

philip

[hdphilip]

moodz,

on your MCP3903, what freq is the xtal? and are you usuing a differential op amp driver configured as a single ended to differential conversion for the adc frontend?

I'm planning on trying it on my qed project.

but in the meanwhile, I'm putting together a few circuits on a pcb to send to the pcb fab house as a "test" board, and i'm including a circuit for the mcp3901

philip

[hdphilip]

...you won the lotto or something

can't win the lotto, all the money i save on tickets, I buy toys with

[moodz]

We are still working out how to do that.

[moodz]

...you won the lotto or something

[hdphilip]

got a new bluetooth adapter (Asus BT211), bluetooth between the uno and my computer works Great!



Also replaced my dual monitors, now their matching(great for programming and PCB layout), and a new video card to drive them

philip

[fmtemp]

Schematic front end

Hi everybody,

I am very impressed by the results you obtain.
I am interresting in testing all your experiments and i am wondering if it would be possible for you to post the front end schematic, and if possible the pcb, you are using for obtazining such results ?

Thank you very much for your job that seem to be really performant.

FM.