Trouble creating a Modulator Circuit

[Kush]

Hi,

    I have to create a modulator circuit in Multisim. The IC Chip that is needed for this circuit is the LM1496, which multisim does not have. After some research, i was able to create my own chip into multisim based of this post (http://forums.ni.com/t5/Circuit-Design-Suite-Multisim/Looking-for-MC1496-any-custom-part-library/m-p...) 

   However when i run the simultion, it returns hese 3 errors;

 ------ Checking SPICE netlist for Act1 - Wednesday, October 12, 2011, 9:38:29 PM ------
SPICE Netlist Error in schematic RefDes '', element 'mixer':  Not enough nodes found
SPICE Netlist Error in schematic RefDes '', element '<unknown>':  Due to errors, the component 'mixer' has been omitted from the simulation
SPICE Netlist Error in schematic RefDes 'u1', element 'xu1':  Not enough nodes found
======= SPICE Netlist check completed, 3 error(s), 0 warning(s) =======

    Below is my circuit file created in multisim.

     Another issue is that after turning the simulation on, when i look at the output of oscilloscope, i see a square wave at the output. I am not sure why this is happening. I am supposed to get a modulated perfect sine wave.

     Your help in this matter will be greatly appreciated. Thank You

- Kush

[Tien_P · Accepted solution]

Hi Kush,

I can see two problems in the component you created, these are:

1.  You have to comment out the first line by adding an asterisk (*).  

* Mixer Subcircuit

2.  Your model mapping is not correct, please refer to this tutorial:

http://zone.ni.com/devzone/cda/tut/p/id/3173

Step 6 and Step 7 explains the model mapping table in Multisim.

The attached file shows how you should map the model.

[Kush]

Thank You Tien,

                       I really appreciate that time that you took for looking intot his matter. I have considered your suggestions and they work 🙂

                       However, there is another problem, when i look at the output on the oscilloscope, i see a square wave output, as attached with this post, instead of a pure sinusiod. Why do you think its doing that?? Is there a way we could fix it?? I have also attached the updated IC. Thankxx

- Kush

[Tien_P]

Hi Kush,

I built the circuit shown in the attached datasheet (Fig 5) and I am getting a sine wave.  I don't know enough about this component but maybe you gain values you choose have too much gain.

[engineering-technician]

can't get crystal to oscillate even with 80Mhz noise to kick crystal into operation. also can't get mosfet to output 32khz signal. just a 15 volt level outputs.

[Tayyab_R]

Please reply to the email I sent you for your support request.