Dear All,

Hope you all are doing well with good health. Here i would like to ask one important question, that i have designed Triangle wave (170Hz) generator's circuit by using xtal osc, it wroks well. i have also designed separately 7.7MHz to 8.7MHz frequency oscillator (Square wave) by using a input/source signal of 170Hz (triangular waveform). For designing and simulation purpose i used LTspice tool.
But when i connected these two modules then i am unable to get output waveform, my system becomes too busy and makes too noisy. if someone can help me in this regards then i shall be highly grateful to him/her, I can provide my schematics.

Anxiously waiting for your kind and quick response please.

Regards

Post a complete schematic as you have it implemente. All the details.

 

Post a complete schematic as you have it implemente. All the details.

Dear Respected atferrari,

Thank you very much for your kind concern. Attached please find the schematics and description as desired, if you need any component or library used in this cct please let me know i will upload, i thought you must have that's why i didn't uploaded. forwarded for your kind information and further necessary help please.

Regards

 

But when i connected these two modules then i am unable to get output waveform, my system becomes too busy and makes too noisy.

Did you follow this part of the datasheet? :-
"V + (Pin 1): Voltage Supply (2.7V ≤ V + ≤ 5.5V). This supply must be kept free from noise and ripple. It should be
bypassed directly to a ground plane with a 0.1µF capacitor."
The LT1799 is most unlikely to work correctly on a breadboard: it needs a properly configured pcb.

 

Dear all

Did you follow this part of the datasheet? :-
"V + (Pin 1): Voltage Supply (2.7V ≤ V + ≤ 5.5V). This supply must be kept free from noise and ripple. It should be
bypassed directly to a ground plane with a 0.1µF capacitor."
The LT1799 is most unlikely to work correctly on a breadboard: it needs a properly configured pcb.

Dear Alec_t,

Thanks for your concern, yes i have considered. If you don't mind then please have look on description file and schematic file which i already attached in post no. 42. please review and help me in this regards, i shall be highly grateful to you for this act of kindness.
Anxiously waiting for your kind and prompt reply please.

Regards

 

replace your X-tal osc + frequency divider simulation with single square wave source (even the single transistor x-tal simulation takes a lot of computer resource)

 

If you don't mind then please have look on description file and schematic file which i already attached in post no. 42.

I have checked those files and run the simulation.
There is no decoupling cap shown (though it wouldn't have much effect in the simulation). That's why I commented about the datasheet.
Is the circuit built on a breadboard?

 

I have checked those files and run the simulation.
There is no decoupling cap shown (though it wouldn't have much effect in the simulation). That's why I commented about the datasheet.
Is the circuit built on a breadboard?

Dear Respected Alec_t,

Thanks for your concern. can you highlight where should i add in schematic if possible, if you have don't mind then with due respect can you simulate this cct for me coz i think my system have some low specification (again if you don't mind).

looking forward your kind reply.

Regards

 

I have run the simulation. It doesn't show any problem.
There is no decoupling cap shown in the schematic. It would be essential in a real-world circuit, though it probably wouldn't have any effect in the simulation.
The cap connects directly across the LT1799 supply pins. Read the datasheet.
You haven't said if you are using a breadboard or not.

 

made the LTC1799 to DiV100 otherwise it further slows down the thing
the only significant bug was opamp output had the same name (node) with the LTC1799 output (you tied these togeter)
just attempted to make it less noisy / faster -- but it's slow -- likely due the poorly written CD4000 library


versus



versus



( http://www.ti.com/lit/gpn/tl3472 , http://www.ti.com/lit/gpn/lm6142 )

 

made the LTC1799 to DiV100 otherwise it further slows down the thing
the only significant bug was opamp output had the same name (node) with the LTC1799 output (you tied these togeter)
just attempted to make it less noisy / faster -- but it's slow -- likely due the poorly written CD4000 library
View attachment 201784

versus

View attachment 201789

versus

View attachment 201798

( http://www.ti.com/lit/gpn/tl3472 , http://www.ti.com/lit/gpn/lm6142 )

Dear Respected ci139,

Thank you very much for your kind help and cooperation. I will consider these changes, but if you don't mind and it take not too much time from your precious time then please simulate the attached cct and upload the screen shot of results for only o/p signals (@OUT4, OUT5). The description is same mentioned in post #42. Actually the problem is same that i am unable to get the simulated the on my computer. It's Request please.

Regards

 

I have run the simulation. It doesn't show any problem.
There is no decoupling cap shown in the schematic. It would be essential in a real-world circuit, though it probably wouldn't have any effect in the simulation.
The cap connects directly across the LT1799 supply pins. Read the datasheet.
You haven't said if you are using a breadboard or not.

Dear Respected Alec_t,

Thank you very much for your kind help. here i would like to inform you that i am not using breadborad. At this stage i just wanna simulate the cct by using LTspice. if you don't mind then can you send me the screen shot of the simulated output please. i shall be highly grateful to you for this act of kindness (as i mentioned before i don't know why i am unable to get simulated results, i think my machine is not too good, sad)

Waiting for your kind response please.

Humble Regards

 

11h and i donno if i got enough disk space = you need to get up with better concept what information you want to retrieve from the simulation . . . besides it's a SIMULATION not the real thing
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
the point is your input is 32768Hz (2¹⁵) → :128 (2⁷) → :2 → 128Hz (2⁷) →→ f.osc : f.3wve = 256:1
the LTC1799 ≈ 8.4MHz (2²⁸) →→ f.3wve : f.rf ≈ 1 : 2097152
you can likely run the required simulations on your own computer :

1. if the quartz and divider work you can replace them with single 128Hz square wave source
2. if the integrators work you can replace them with 128Hz triangular wave source
3. to test the modulator you can bring that 128Hz closer to the 8MHz say 1:6 to 1:32 or higher if the LTC1799 does not respond linearly enough to the fast varying input

 

The sim works, albeit excruciatingly slowly because you are asking it to do so much at once.
As suggested above, check the circuit in sections. In the sim result below I replaced the oscillator, divider and integrator (all simulated ok previously) by a simple ramp generator (labelled TestOnly) to test the modulator. This reduced simulation time from the 11 hours which ci139 experienced to about 1 second !

 

11h and i donno if i got enough disk space = you need to get up with better concept what information you want to retrieve from the simulation . . . besides it's a SIMULATION not the real thing
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
the point is your input is 32768Hz (2¹⁵) → :128 (2⁷) → :2 → 128Hz (2⁷) →→ f.osc : f.3wve = 256:1
the LTC1799 ≈ 8.4MHz (2²⁸) →→ f.3wve : f.rf ≈ 1 : 2097152
you can likely run the required simulations on your own computer :

1. if the quartz and divider work you can replace them with single 128Hz square wave source
2. if the integrators work you can replace them with 128Hz triangular wave source
3. to test the modulator you can bring that 128Hz closer to the 8MHz say 1:6 to 1:32 or higher if the LTC1799 does not respond linearly enough to the fast varying input

View attachment 201802

Dear Respected ci139 ,

First of thank you very much for your great effort and help. i am really so thankful to you for this act of kindness. you did a great work and spare time for me.. I have lots of good wishes for your future endeavors.
Thank you very much, at this stage i just wanna confirm through simulation that circuit is working or not, your results reflects that there is no problem is cct, i works fine.
So nice of you .. !!!

Regards

 

The sim works, albeit excruciatingly slowly because you are asking it to do so much at once.
As suggested above, check the circuit in sections. In the sim result below I replaced the oscillator, divider and integrator (all simulated ok previously) by a simple ramp generator (labelled TestOnly) to test the modulator. This reduced simulation time from the 11 hours which ci139 experienced to about 1 second !

View attachment 201835

Dear Respected Alec_t,

First of thank you very much for your help. i am really so grateful to you for this act of kindness. you did a great work and spare time for me.. I have lots of good wishes for your future endeavors.
Again thank you very much for you kind cooperation.

Regards

 

Dear Respected

I have lots of good wishes