DDS based Chirp Generator output mixed with Sinusoidal signa

[shitaldesai]

AWR: DDS simulation

Hello Everyone,
Wish You All A Happy New Year. I have a simple problem that I am trying to simulate in Microwave Office. Since, I am a novice user of MWO and in general AWR, I appreciate some help in this regards. The problem goes likes this:

A DDS based Chirp Generator output (FMCW Liner Chirp) is mixed with a Sinusoidal signal. How do I model this in MWO? Since this is a mixed signal design problem, I was wondering whether firstly it is possible. If yes, what is the best way to do it? The specs are as follows:
(1) The DRO is used to generate a 7.129 GHz signal (sine wave)
(2) DDS chirp generator generates a chirp from 100 to 106 MHz
(3) Both the signals are mixed using a upconverter mixer.

I appreciate some suggestions or ideas to go about with this. I think I should be able to grab some Mixer design ideas from the tutorials, should get the sinusoid oscillator source from the library, the problem I guess would be the DDS chirp generator. Correct me if I am wrong.

Regards,
Shital

 

[Manjunatha_hv]

Re: AWR: DDS simulation

Hello shitaldesai,

It can be generated using AWR Visual System Simulator (VSS).
Use VSS primitive blocks to construct a chirp signal. A SAW source in combination with a TONE source is used to drive an FM transmitter.
The saw tooth's amplitude swing in conjunction with the frequency sensitivity (K) of the FM transmitter sets the bandwidth (frequency range) of the chirp signal.

With the amplitude swing of the sawtooth set to +/-2 and K of the FM transmitter at 3.5MHz, the bandwidth of the chirp signal is 14MHz.

The chirp signal’s center frequency can be changed by setting the variable fc to another frequency.

An example on Chirp signal is available in the installation folder of AWR products...
I have attached the block diagram picture for your reference....


---manju---

 

[shitaldesai]

AWR: DDS simulation

Dear Manju,
Thank You very much for the solution. I did figure out the chirp generation part and now I am trying to upconvert the chirp to RF (7GHz). In the process, I am facing some problems with the tool usage....Hopefully, should get it sorted with experience. Do you mind if I send you an email in case I have problems?
Thanks again
Regards
Shital

 

[Manjunatha_hv]

Re: AWR: DDS simulation

Dear shitaldesai,


It's nice to know that you have solved your problem...
your welcome to send your problem or issues to my email ID: manjunatha_hv@ieee.org
I will try to help my level best...



---manju---