Measuring phase angle shift

[ivconic]

Take a deep breath; i finally founded schematic of device with which we can simply measure,scope or follow phase angle shifts...Sort of diy, easy to make, suit,cute...yeah!
This could be done as standalone measuring instrument and also could be included in md design as extended discrimination stage...Yeah again!
This was taken from old "Wireless World" magazine from august,1979.
Issues (for me) here is that ic pins are missing. I am not pretty familliar with 4007 and 4081....so this logic draw is confusing me a bit....
That's why am i posting it here...
Any suggestions?

[ivconic]

Desert...wind is blowing...dust...cactus alone...
And nobody really interested here!? It seems you didnt understand real potential of this schematic? Carl is only one who can afford being uninterested since he already have pretty descent phase angle shift measuring instrument, so far as i know.
With this we can observe phase beahvior while nulling coils...man oh man!?
Also can observe phase behavior after, when coil is finished, attached to detector, and moving various metals over coil we can observe differences in phase angle; which metal shifts phase more or less. But real cake would be if we include this in our metal detector design as extended discrimination stage.
Indication here is not an issue. At the moment, vu scale is used.Could be easily changed to vco audio...Splendid idea? Ha?
So many various ways to use this...
Completely analogue, yet has potential as much more complicated projects...
Only thing not clear to me yet is that inverter. Here 4007 is used. I am not sure about 4007 setup here yet. Active or passive load? What to do with unused pins? In this setup two of cd4007 must be used. Since power supply is strictly 12v (due used components values) than 5V regulator must be included to supply 4007 separately..or not?
4007 acting as inverter is sure best thing here. But could it be replaced with other kind of inverter circuit?
To many questions. First thing is to distinguish proper 4007 pin assgnments here...
Once this is finished and working...it will open quite new chapter on this forum, i am sure!

[ivconic]

I tried to "decipher" this more. Not sure i this is correct?

[ivconic]

It will be easy to calibrate VU to zero phase angle.Simply to load ref.in and signal inputs with same signal, adjust zero with trimmer and that is all.
Later ref.in will be reference taken from TX stage and signal input will be fed with RX signal. Any angle shift would be easilly indicated on VU scale...cute!
Does this need so much imagination to understand?
C'mon folks...!

[ivconic]

Or...going further i am thinking how to make this more portable;
could 4007 part here been replaced with IRF7107,IRF7309 or simillar?
I am really novice in this things,need help here...
Must be that someone here know this better than me?

[Carl-NC]

This reminds me of a classic phase detector in a PLL. The outputs of the NANDs are just pulses that vary in duty cycle due to the phase difference, and the duty cycle is seen as an RMS value by the meter. No reason why you can't run the whole thing from +5V. No reason why you can't put the whole thang in a PIC, within certain limitations.

- Carl

[ivconic]

Thanks Carl! This can really be used as standalone instrument - huge help during coil balancing. First idea was to make it for that.
I was wandering about 5v supply. Now when you saying it will work - even better. Also to make this even more portable i was thinking to use CA3240 instead 2 CA3130. Logically no reason why it shouldnt work?
PIC...yes, small 16F84 can handle this task easilly. Instead VU scale, LCD could be used also....

[Qiaozhi]

Both the CD4007 and the CD4081 are CMOS devices that have a recommended operating voltage of between 3V and 15V. So there's no need to use a stabilized 5V supply.
A CA3120 should be a good replacement for the CA3130.

I was also thinking this looks like a classic phase detector from a PLL.
Your main problem will be calibrating the meter. Let us know how well it works.

[Max]

Take a deep breath; i finally founded schematic of device with which we can simply measure,scope or follow phase angle shifts...Sort of diy, easy to make, suit,cute...yeah!
This could be done as standalone measuring instrument and also could be included in md design as extended discrimination stage...Yeah again!
This was taken from old "Wireless World" magazine from august,1979.
Issues (for me) here is that ic pins are missing. I am not pretty familliar with 4007 and 4081....so this logic draw is confusing me a bit....
That's why am i posting it here...
Any suggestions?

Hi,
cd4007 are dual complementary inverters, then 4081 are NAND gates and 4013 are very common D-type flip-flops...

Seems easy... but what about precision ? I'm not sure this is the best way to know about phase shifts...

As Carl said... maybe you can do better with a PIC.
A PIC can use e.g. a 20MHz clock signal to have really accurate timing and internal timer to count for time intervals: if you make it autorange and lock to
signal frequency you can easy find phase shifts making some calculations and measure will be really accurate, probably some 1/10 degree on low frequency signals like 10-15Khz.

The advantage of this simple circuit is that you don't need to program an MCU to get it work... but I always think the best way to know about phase shifts is using really accurate frequency locking or for fixed freqs using quartz reference signal to measure time intervals.

Anyway... I'm interested too in results... cause it's boring to wire each time scope to look at shifts... so please let me know of any progress with it.

Kind regards,
Max

[Max]

I tried to "decipher" this more. Not sure i this is correct?

Hi,
dechypering it a bit more:

2 parts ca3130 are zero crossing detectors... they are open chain connected so acts like comparators, the 2 diodes are for input protection and will limit voltage transients to -0.7 ..+0.7V at each input used.

Capacitors of 0.1u used for decoupling Dc component; resistors there are voltage divider... and impedance stuff... not important.

The upper zero crossing detector will give positive saturation when signal (reference) will rise over zero volt ; the second the opposite, give positive saturation when signal to measure goes down zero volt, negative otherwise.

Upper NAND gate will get output at 0 just when both inputs are at 1, so at positive voltage: this happens when reference signal is more than zero volt and when "signal" at second input is lower than zero volt.

The second NAND gate gets opposite signals than the upper so its output is always 1 except when both signals out of comparators are 1, so its output is 0 when reference is under zero and signal is over zero.
This is a useful trick to double voltage provided to meter using reverse edges of transitions to count for phase shift.

The NANDs drive a rectifier diode each branch that will provide DC output for the meter--> the current flowing in meter depends directly on how much wide are positive pulses from nand gates... so on duty factor of these two signals.

These 2 signals depends linear way on pphase shift:

- when signals are in phase the duty factor is zero... cause when one comparators out are NEVER 0 same time but always 0-1 or 1-0

- when signals are out of phase the duty factor is >0 , depends linear way on shift value and maximum at 180° off phase cause comparators out are both 0 for the maximum time (1/2 period of signals)

The flip-flop will be periodically resetted by first comparator at each positive edge of reference... and used to detect more than 180° phase shift.

As said seems easy stuff... and it is... BUT I see problems having hi resolution using an analog meter there... too old approach and good maybe to detect 2-3degrees variations.
There's also non-linearity of diodes to keep in mind and maybe fast ones like some shottky will perform better there... and also I don't understand why there isn't any little cap to hold voltage a bit! This seems truly a mistake there! I will add a 2.2 uF there or 10uF.

Kind regards,
Max

[ivconic]

Sure thing, i will report here.
Accuracy...well,certainly this can not compete MCU but enough for scoping some phase behavior. Recently i "discovered" another thing (i am learning yet); null balancing is not end of a story with coil. So far i tried hard to achieve absolute null. And managed so so. Those coils are working pretty good but i noticed some lacks. Discrimination is better at coils with a bit higher residual voltage than coils i usually did "best" !?!?!? Pretty confusing!?
Few coils i managed to null at almost absoulte null lacks of being deaf at some metals - obviously phase is somehow shifted more than needed. I cant tell a thing about this, simply i dont have scope and phase shift measuring instrument.So i was thinking to make this and do some extra investigations on such coils. No, it was not as i thought earlier - closest possible balance to null is not solution to all problems....pitty. I can be sure this is about coils cose already do have comfort to have few same detectors and coils, so possibillty that something is wrong with detector is out of question. It is something about coils. Without scoping phase angle i simply could not go further with this. I will wander in a fog. I simply need this or similar instrument. Eh...if i had the one Carl posted picture on other thread...

[ivconic]

I did some fast pcb. Design is not some state of the art, but will do the job for fast testing. If this turns to work than i will draw better pcb...

[ivconic]

Damn! This pcb will never work, until correct supply pins on CA3130!!! Instead 7. pin i connected 8. pin!!! What a hurry!? Only that i spotted so far.....Damn!

[ivconic]

This one is correct!
Huuh!

[ms.nomi]

This one is correct!
Huuh!

Hi, good work

Please result after test this circuit

Thx Michal

P.S. Sorry my bad english