Carl's fluxgate Gradiometer ckt.

[damiafix]

Hi damiafix.
Do not forget whole Test8 from extortion how:
Test: 3j, 3k, 3l, 3m, 3n, 3o, 3p, 3q!
Best regards Chris.

Hi Crhis,
the whole test8 with all the 64 samples, is available at the follow link:

AD557 test: 3j, 3k, 3l, 3m, 3n, 3o, 3p, 3q


Have a good night, Dam.

P.S. I think that this thread will be a usefull guide for those who want to understand, step to step the FMX-1 or to found problems on the own mag!

[Krzysztof]

Hi damiafix.
Do not forget whole Test8 from extortion how:
Test: 3j, 3k, 3l, 3m, 3n, 3o, 3p, 3q!
Best regards Chris.

[damiafix]

Hi Damiafix.
Now its time for Test9.
Terms: R6 determine to hear loud signal in a wide range.
Set a FGM3, SCL007, Logic Analyzer, AD557, LM in its place on the PCB.
Stimulate sensor and listen.
Test10.
FGM3 Add a second and see what's going on.
Position of both FGM can be anything but on the table!
Stimulates only one FGM.
You are already close to finals and good luck!
Best regards Chris.

Hi Chris,
many thanks, about the waveforms I understood, I've read wrong the schematic; synopsis for everyone:






LM393 PIN3 (Input A/B wired, from LM393 I/O: - "A" from Fig.1 Simplified VCO)



LM393 PIN1 (Output A from LM393 I/O: - "E" from Fig.1 Simplified VCO)



LM393 PIN7 (Output B from LM393 I/O: - "C" from Fig.1 Simplified VCO)


for the next test (9) I hope to make it, as soon possible! Many thanks again!

Best regards, Dam.

[Krzysztof]

Hi Damiafix.
Now its time for Test9.
Terms: R6 determine to hear loud signal in a wide range.
Set a FGM3, SCL007, Logic Analyzer, AD557, LM in its place on the PCB.
Stimulate sensor and listen.
Test10.
FGM3 Add a second and see what's going on.
Position of both FGM can be anything but on the table!
Stimulates only one FGM.
You are already close to finals and good luck!
Best regards Chris.

[Krzysztof]

Hi Damiafix.
Everything OK!
In thee is a little mistake.
The description of the scope PIN1 is to be "E" is output to the amplifier speaker.
In the description of the last scope Pin 7 is to be "C" is control PNP transistor.
Since Pin6 is soft (float voltage, depending on the capacitor charging current - the voltage drop across the resistor internal Pin14/13 AD557) is your charts are great!
And now you still care about listening experience and do well Test8 in its entirety.
I asked them to drive the implementation of extortion, as in Test3j until Test3q how you take the time to do the MP3.
Then you can hear the signal frequency and signal level.
It is perfect for pre-selected, yet the extent of your table rezystancjii R6.
This allows for a nice tone and does not deal with this on the ground.
He will be checked.
In trials with 2 FGM3 will not be wondering what you hear, you will no longer sure!
Best regards Chris.

[damiafix]

Hi Chris,
those are the results of the oscilloscope analysis to the Vco, LM393. The points are refered to the fig.1 Simplified VCO and fig.2 Vco Waveforms of the original Carl's document.
I've measured with the LM393 on the PCB.

See yourself:

LM393 I/O:


The VCO as explained from the Carl's document of the FMX-1:


My results, for R6 0KΩ - AD557 Pin8 5v, Pin1/7 GND:

LM393 PIN3 (Input A/B wired, from LM393 I/O: - "A" from Fig.1 Simplified VCO)


LM393 PIN1 (Output A from LM393 I/O: - "C" from Fig.1 Simplified VCO)


LM393 PIN7 (Output B from LM393 I/O: - "E" from Fig.1 Simplified VCO)


Vref1, Pin 2 (B): 3,51v
Vref2, Pin 6 (D): 2,03v

The waveforms of the LM393's outputs, seem inverted, respect to the Fig.2 Vco Waveforms (from the Carl's document) and the Output B "E" for the Fig.1 Simplified VCO is very different from the waveform "E" shown on the fig.2. Maybe there is a error in the nomination of the waveforms of the fig.2, or maybe I should to do the measures with the LM393 out the PCB!?!?

All the best, Dam.

[damiafix]

Hi Crhis,
again here for share the results:


TEST 3j - AD557 Pin 1: 5 volts Other pin to GND
R6: 0KΩ, 0.5KΩ, 1KΩ, 1.5KΩ, 2KΩ, 2.5KΩ, 3KΩ, 4,5KΩ


TEST 3q - AD557 Pin 8: 5 volts, others pin to GND
R6: 0KΩ, 0.5KΩ, 1KΩ, 1.5KΩ, 2KΩ, 2.5KΩ, 3KΩ, 4,5KΩ

You could to see that, from R6 2,5KΩ to 4,5KΩ, is very hard to hear the sound, the last better audible sound is for R6 1,5KΩ, but from R6 2KΩ to R6 4,5KΩ the volume is much low.

Many thanks again for your help.

Have a good day, Dam.

[Krzysztof]

Hi Damiafix.
Hooray for good ideas, those MP3 are super.
These results show that the R6 is set around 0.5 - 1.5 Kom, to obtain a sensitivity at low voltage.
Coupled test7 as the voltage below 0.5 V blocks Q1, what shown in MP3 (V = 0.2 V) is a signal to the LCD refresh rate from your digital meter!
It turns out that all components are OK.
Now the next test of cooperation and parts AD557 V / f.
Note that the actual system voltage 0 - 2,5V PIN14/15 occurs.
And there it should be measured.
PIN16 is now about 1V higher voltage (0.7 V + (Ic/R6).
Test8.
Measurement conditions: AD557 set separately as in post # 24; PIN14, 15.16 system connected to the V/f on the original PCB; attached to the analyzer enter PIN1 - PIN8 AD557.
Forcing voltage as Test3j - Test3q.
PIN14/15 voltage measurement only controls - should be as before in Test3.
Setting R6: 0, 0.5, 1.0, 1.5, 2, 0, 2.5, 3.0 Kom.
The results of the hearing. MP3 would be nice.
Best regards Chris.

[damiafix]

Hi Chris,
please, listen yourself the results, from this link.

All the best, Dam.

[Krzysztof]

Hi Damiafix.
I found something for you.
Winscope can directly or through an additional snap-checked.
http://www.qsl.net/om3cph/sb/winscope.zip
http://www.qsl.net/om3cph/sb/dcwithsb.htm
http://www.elektroda.pl/rtvforum/dow...74aff6ec1dbdca
http://www.elektroda.pl/rtvforum/dow...74aff6ec1dbdca
Best regards Chris.

[Krzysztof]

Hi Damiafix.
See post # 21 Figure 2 and chart post # 18.
This combination means that the output voltage (0-2,5V) AD557 will PIN14/15! (Voltage Repeater).
It also means that the collector current of Q1 is equal to the voltage at PIN14 / 1.62 Kom.
This loads the current C5.
Of course, the resistance of R6 can not be too big, not too much pent-charging current, is also used to determine the operating point LM393 and Q2.
Tension on the C5 and C6 are important for determining size power saws and range frequency.
To this must be sound in reception was nice, otherwise it quickly tired of hearing and harder to recognize the change in frequency.
Subjective feelings are important!
Sincerely, Chris.

[Krzysztof]

Hi Damiafix.
Everything will be fine and free You do not need the frequency meter.
Your measurement is your ear, you hear the signal from the speaker.
Frequency easily done by a computer sound card. The simplest program "Winosc" I will when I find bearings in the net.
Then you will see the images from anywhere in the Part V / fi compare to figure Carl.
Test6 is there to find the best operating point V / f.
The resulting signal is the most useful and most famous in the 100Hz - 2kHz.
Above 4kHz means a very strong signal, or interference, hardly use it.
Tenderest place is at the lowest frequencies. However, assuming the presence of EMI at the beginning of 20Hz can be ignored as a disturbance, the rest is pure signal.
Of course, like Walk a little more, you can set a threshold of 0 V at 30Hz, and then you have the maximum sensitivity and auditory impressions like in a normal MD!
Best regards Chris.

[damiafix]

Hi Chris,

H
Test7:
Measure the resistance between the AD557 PIN14 - PIN13.

1.62 KΩ

Measure the resistance between the PCB blank PIN14 - PIN13.

18 MΩ (from the dac socket without the IC)

About the test "systen V/f " I don't understood where I must to measure the results; maybe the frequency value on the VCO output (Pin 1 of the LM393)?
Unfortunately I don't have a frequency meter (I must to buy one, I know )for now, I could to use a frequency meter software? The frequency range, that I must to measure is very low (5-30hz) and from 0hz to 20.000 hz an pc audio card should to be suitable, right? For the output of the sensor is different, the pulse train is in the 100khz range...
What do you think?

All the best, Dam.

[damiafix]

Hi Chris,
many thanks, I'll ceck again the pcb!

All the best, Dam.

[Krzysztof]

Hi Damiafix.
Out of curiosity.
Test7:
Measure the resistance between the AD557 PIN14 - PIN13.
Measure the resistance between the PCB blank PIN14 - PIN13.
Best regards Chris.