Search Results for 'DPSK'

[Ahmad Mahmood]

I want to implement DPSK(BPSK) modulator in optisystem 13 using delay feedback loop but I dont know what component should I use in place of 1 bit delay. Moreover I cant use the output of bit sequence generator at the input of electrical XNOR gate. Balanced modulator is also not present in optisystem 13. Kindly Help and guide. Schematic is attached.

Attachments:

1. 

   DPSK-modulator.jpg
   

[Subhash AryaParticipant]

Dear Debanjan,
I appreciate Alistu for his deep knowledge and experience of using Optisystem. After matching the bit rate and symbol rate the DPSK is giving its output. Please check it whether it is coming as per expectations. Simulated Circuit is attached here.

Attachments:

1. dpsk-1.osd

[Debanjan Sarkar]

Dear all
I am using the evaluation version of optisystem 13. i have encounter one problem while running one inbuilt example of “DPSK Step 3 – Pulse generator and decoding.osd”. According to me the output of DPSK sequence decoder should be same as input bit stream. But when I tried to run, the output of DPSK sequence decoder is showing only 0. please check the attachment .Please help me to understand what is wrong as I am new to this system.
Regards

Attachments:

1. 

   Untitled.jpg
   

[gaganpreet KaurParticipant]

Hi abhishek sorry for confusing u actually i wanted to refer to post no. of alsitu #24565 in response to DQPSK by dhiman in which alsitu suggested to generate DQPSK using DPSK (which is there in optisystem 7.0). Yes screenshot i referred to suggests use of RZ insead of gaussian to generate RZ-DQPSK. i hope i am able to make it clear now.

[gaganpreet KaurParticipant]

yes Sam, i am refering to design of DP_qpsk suggested on this forum which uses 4-DPSK precoder. i designed a single laser source modulated by DPQPSK as .osd now is it possible that i use this .osd project/file as component in another optisystem design.i hope i could make it clear now

[Ashu vermaParticipant]

Welcome,since you are asking about best modulation format then i would suggest you the DQPSK.However now all the modulation formats are like NRZ RZ DPSK MDRZ etc are provide different results and performance in different systems.Moreover you can try them by your own.lot of article you find on net regarding these formats and it is hard to find only one format to use which comes out best because different papers has differebt modulation format best according to scenario.For example if you kept non linearities off then Dpsk performs best and csrz mdrz also provide good results than Rz Nrz due to less prone to dispersion and are bandwidyh efficient .But where you consider non linearities ,trend become opposite ,here Rz performs better due to less prone to non linearities but yes more dispersion and bw requirements.So there is trade off between these .As i have seen many papers on PON and maximum use DQPSk has been analyzed for NG PONS .

[UMAR FAROOQParticipant]

Thanks sam for your reply.Can you please tell me which modulation format is best regarding WDM system for better reach and other considerations i want to improve the system by designing transmitter.I used DPSK modulation format at transmitter side and got good results now please tell how can i further improve the system? Please see the attached paper.

Attachments:

1. 4yousaf_SPIE_-015001_1_1357581874_11.pdf

[alistuParticipant]

Hi Dhiman,

Are you seeking something other than using the Optisystem DPSK component, setting bits per symbol as “2” in the component properties (to make it DQPSK), and setting the frequency as 4 0GHz? (I assume you need this for the system you introduced in the local oscillator topic)

Regards

[alistuParticipant]

Thanks for uploading the paper. I don’t think you need carrier generator block, as DQPSK signal generated by Optisystem DPSK block actually has a carrier whose frequency you can determine in the DPSK component properties (it’s the first parameter there with the default value of 50 MHz). That parameter is defined as “the frequency of the signal carrier” in the help section.

[alistuParticipant]

Thank you for the snapshot. The image shows only a small part of the whole system. If the frequency that is supposed to be generated by the mixer the frequency of the signal carrier, isn’t DPSK block “frequency” parameter what you are looking for?

[Ashu vermaParticipant]

Agree with Alisthu,you can check the tutorials and you can easily get help.Check the link,optiwave examples like DPSK and DQPSK used this type of detection

Advanced Modulation Formats

[Ashu vermaParticipant]

hi Mahammed, as far as i know MZI switch has two input ports and two output.Even i have read some papers and their diagrams indicates about coupler two ports.One thing you can do that connect null signal to one port as i have seen in DPSK receiver.But didint get exactly which MZI switch you referring to.Even i have looked it in another software,component is same as in optisystem.

[Hager]

DPSK is one of ROF modulation techniques,in this simulation at Tx the data are used to modulate three different carrier having frequencies 10,15,20 GHZ ,bandwidth= 1.5*Bit Rate which Bit Rate varying (0.5,1,1.5,2)GHZ These signals are
then combined using electrical power combiner and this combined signal is used to modulate an optical carrier of
frequency 193.1 THz using mach zehnder modulator (MZM), transmitted through the single mode fiber length varing (10,20,30,40 KM)
at RX These optical signals are then passed through optical band pass filters (frequencies 193.110 THz, 193.115 THz, 193.120)
in my simulation i used opti system 13 , Bit Rate 2 GHZ, length of SMF is 40 KM.
I modified it by using VCSEL instead of CW Laser , EDFA instead of optical amplifier and one user only for bit rate=10GHZ , varing distance from 10 km to 120 km but I found degradation results in BER analyzer, plz modify it for me

[Hager]

DPSK is one of ROF modulation techniques,in this simulation at Tx the data are used to modulate three different carrier having frequencies 10,15,20 GHZ ,bandwidth= 1.5*Bit Rate which Bit Rate varying (0.5,1,1.5,2)GHZ These signals are
then combined using electrical power combiner and this combined signal is used to modulate an optical carrier of
frequency 193.1 THz using mach zehnder modulator (MZM), transmitted through the single mode fiber length varing (10,20,30,40 KM)
at RX These optical signals are then passed through optical band pass filters (frequencies 193.110 THz, 193.115 THz, 193.120)
in my simulation i used opti system 13 , Bit Rate 2 GHZ, length of SMF is 40 KM
I have a problem in matching o/p of BER analyzer of my simulation with this paper plz modify it and attach it for me.

[Taiwo Ambali AbiolaParticipant]

Interesting issue raised by Muhammad Boron., However the topics relating to the usage of BER test set in place of BER analyzer have been discussed previously in some of the earlier posts. Any of these might be beneficial to you. I think you have to check the components property of the BER test set before you can actually read the received BER information.

DPSK with optical modulation

WDM QPSK THROUGH FSO LINK

OWC QPSK Design

visible light coomunication

https://optiwave.com/forums/topic/how-do-we-connect-bre-analyzer-to-a-dp-qpsk-reciever/ and several others.
enjoy!!!