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FCL-X Frequency counter accuracy

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FCL-X Frequency counter accuracy

Postby gassanov » Mon Oct 05, 2009 1:24 pm

hi all

i just finish build my fclx meter,everything working fine except the frequency counter...the frequency counter have a bad accuracy...i already try to trim the tiny capacitor trimer on the 4 mhz crystal but the frequency reading still inaccurate.

for example:i inject 1mhz signal and the meter shows me 0.999.286.
it happens in all frequency from 1-30mhz.

can anyone give me a clue or sugestion.

thx.

Gassanov Fuad Iskandar
gassanov
 
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Re: FCL-X Frequency counter accuracy

Postby mvs sarma » Tue Oct 06, 2009 1:27 am

gassanov wrote:hi all

i just finish build my fclx meter,everything working fine except the frequency counter...the frequency counter have a bad accuracy...i already try to trim the tiny capacitor trimer on the 4 mhz crystal but the frequency reading still inaccurate.

for example:i inject 1mhz signal and the meter shows me 0.999.286.
it happens in all frequency from 1-30mhz.

can anyone give me a clue or sugestion.

thx.

Gassanov Fuad Iskandar


please read the article where the accuracy is mentioned as * Nearly 2% accuracy
thus i feel it is reading 999KHz for 1MHz
perhaps you may depend on another design as far as Frequency measurement is concerned
Regards
Sarma
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Location: Hyderabad, India

i still looking and for other possibilities

Postby gassanov » Tue Oct 06, 2009 2:15 am

:( i'm craying here...hikhikhik

thx for super fast response.

i still looking and for other possibilities,like changing the timer.etc.

is it possible to fix by changes the timer?
can anyone give me the original .asm file?

this is great tools...i still thinking that we must fix the inaccuracy.

sorry for my bad english

thx.
gassanov
 
Posts: 6
Joined: Tue Sep 29, 2009 10:07 pm

Re: i still looking and for other possibilities

Postby mvs sarma » Tue Oct 06, 2009 10:23 am

gassanov wrote::( i'm craying here...hikhikhik

thx for super fast response.

i still looking and for other possibilities,like changing the timer.etc.

is it possible to fix by changes the timer?
can anyone give me the original .asm file?

this is great tools...i still thinking that we must fix the inaccuracy.

sorry for my bad english

thx.
dont have to cry or crave
by the way, how do you say that your 1MHz is SO VERY accurate that you suspect the Freq counter section of the meter?
I suggest that you may check the 1MHz with any know standard freq counter. Also check the 4MHz oscillator of the FCL-X meter with the same counter.
After these tests, you may measure the 1MHz output. Let us see how it turns out. all the best.
Regards
Sarma
mvs sarma
 
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Location: Hyderabad, India

Re: i still looking and for other possibilities

Postby gassanov » Wed Oct 07, 2009 12:26 am

mvs sarma wrote:
gassanov wrote::( i'm craying here...hikhikhik

thx for super fast response.

i still looking and for other possibilities,like changing the timer.etc.

is it possible to fix by changes the timer?
can anyone give me the original .asm file?

this is great tools...i still thinking that we must fix the inaccuracy.

sorry for my bad english

thx.
dont have to cry or crave
by the way, how do you say that your 1MHz is SO VERY accurate that you suspect the Freq counter section of the meter?
I suggest that you may check the 1MHz with any know standard freq counter. Also check the 4MHz oscillator of the FCL-X meter with the same counter.
After these tests, you may measure the 1MHz output. Let us see how it turns out. all the best.


thx for your response sarma.

i already did,sarma.i'm using PLL as signal my generator and use VK3BHR F-Counter.
i also check with VK3BHR the 4MHz oscillator of the FCL-X and tune the small varicap to 4mhz precisely.
i know about 2% accuracy but i guest the 2% inaccuracy is not effect the frequency counter.

thx.

gassanov fuad iskandar
gassanov
 
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Postby vu3wij » Mon Oct 12, 2009 10:14 pm

Hi,
Instead of adjusting the 4MHz crystal to its exact resonance frequency, try to trim the trimmer across the PIC oscillator pin, so that the display shows the exact frequency you measure. I think doing this will solve your problem.

SHAJI
VU3WIJ
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Postby gassanov » Mon Oct 12, 2009 11:43 pm

vu3wij wrote:Hi,
Instead of adjusting the 4MHz crystal to its exact resonance frequency, try to trim the trimmer across the PIC oscillator pin, so that the display shows the exact frequency you measure. I think doing this will solve your problem.

SHAJI
VU3WIJ


yes
i already try to adjust the trimer the tiny cap to any hf spectrum (1-29.999mhz)still have no luck. for example:

i inject 29.999.999mhz signal and adjust the trimmer cap so the meter show "29.999.999mhz" and after doing the trimer calibration i inject 1mhz the meter show 1.999.928. and vice verse.

i also try to replace the 4 mhz crystal with external oscillator to pin no 16 pic.i get the same result. the meter never shows me the righ frequency.

another experiment i want to try is,
1.adjust the timing on the pic using asm editor
2.replacing 16f84 with 16f628.

thats why i asking you to sent the .asm file to my email.
after made some modification i sent it again the asm file to you.

here's my email address:
gassanov@yahoo.com.

thx mr shaji.

gassanov fuad
gassanov
 
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can anyone help?

Postby gassanov » Fri Oct 16, 2009 8:33 am

can anyone help?
gassanov
 
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Postby vu3wij » Sun Oct 18, 2009 9:04 pm

Hi,

I have sent ASM file with both 16F84 version and 16F628 version. Make changes and see whether it solves your problem.

SHAJI
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Postby s56zvd » Sat Oct 31, 2009 12:17 am

Hi,
I was made FCL meter and working OK, but I have one problem.
When switch to measure Xtal working only to 10,5Mhz. Oscilator working with xtal for 14,315 Mhz but nothing on display. On pin 3 on pic I have signal but not on display.
Frequency measure working to 30 Mhz with signal 0db.

73
S56ZVD
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FCLX-TAL METER NO X-TAL AND FREQUENCY MEASURING

Postby YO8TJJ » Sat Nov 14, 2009 1:26 am

Hello guys,

I've just finish to build the FCLX-TAL METER and i can't measure the frequency and the x-tals. The capacitance and inductance scale works very well but i can't measure values of capacitance over 10 nf! Can anyone help me with a solution ? Or maybe somebody has the same problem and can tell me a solution!

Apologise for the bad english language!

Thanks!
YO8TJJ
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Inacuracy

Postby VE5GA » Thu Dec 08, 2011 9:44 am

I am having the same problem with inaccuracy of the readout in both the crystal and frequency modes even with the pic's crystal trimmed to exactly 4 mhz. The readout is consistently low.
Has anyone found a way around this issue?

VE5GA
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Postby mvs sarma » Thu Dec 08, 2011 11:22 am

Perhaps you should avoid loose wires using on pcb switches. Try to use Frequency range alone (remove the switches) and connect the input freq or crystal very close to pcb and check once.
Regards
Sarma
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Error

Postby VE5GA » Sat Dec 10, 2011 1:26 am

The frequency readout is rock solid but is consistently low. Removing the wires from the board to the switches had no effect. Pulling the crystal frequency with the trimmer brings the readout closer but can't be shifted enough to compensate for the error. I assume the problem is in the pic code and the timing period, but may be beyond the capabilities of the 16f84. But I know little about writing code so it may be the end of the line for my troubleshooting.

VE5GA
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Re: FCL-X Frequency counter accuracy

Postby Ernando » Mon May 26, 2014 10:06 pm

hi,my FCL-x meter was working good since last week,
when i turn it on,it starting on LCD like a setup mode,
it only shows some like it Constant
X1000

could you tell me what problemm it is?


tanks

Ernando@oi.com.br
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