Author Archives: Chutham

Gambatte ne!!!!

If you can still remember the ELCA festival, last time we made a donation for Japan and we played a song for Japanese friends.

This time the disaster moved to Thailand. Almost half of the country is being submerged and sadly it will last for more than a month from now.

Japanese friends also play a song for Thai people. It’s called ‘Gambatte ne’ which means ‘keep fighting.’

This is to warm up our ELCA festival 2012. We will have a brand new ELCA song and a special song for Thailand as well.

Again, we r not going to drink for nothing but part of our drinks will go for recovering Thailand and to tell Thai people ‘Gambatte ne!!!"

Be prepared for the first rehearsal.

Mr. Brain: The Role of Neuroscience in Crime Investigation

More than a week ago, Wouter recommended a Dutch documentary ‘Mystery of the brain’. I believe that the documentary must be very interesting but unfortunately I don’t understand Dutch… What a pity.

I also would like to share my experience with you all in a way that is more relaxing. There is a Japanese TV series called “Mr. Brain” that we can watch online at

After being busy with my research, watching it reminds me of myself and my work. It makes me smile sometimes. In these series, we will see how the detective and the neuroscientist deal with each other in a bitter-sweet-funny way. Understanding the brain helps a lot in interpreting the evidences that are left behind at the crime scene. Whenever the story goes to a complicated theory of neural processing there will be animations popping up to explain in a very cute way.

It is also good for kids, I think.

A few useful things I got from watching it:

  • I enjoy eating bananas more
  • I know where to sit in front of the girl I meet for the first time
  • Color comes first, shape follows but sound is the most powerful
  • We are using only 5% of our brain. There are still more than enough resources in our brain
  • For creativity, just don’t give up

Like Neil Yongjia said before singing: “I hope you’ll enjoy.”


Smaller can be better

After the 2011 edition of ELCA Music Festival, I was dragged (by some mysterious power) deep into the idea that came to my mind around three years ago. At that time, I was trying to simultaneously linearize and reduce a transconductance of a Gm cell (VI converter circuit) for very low frequency biomedical filtering. The linearization and transconductance reduction were successful but the success came prices that I needed to pay:

  1. circuit complexity which is really unfriendly to weak inversion CMOS.
  2. more current consumption which was not surprising. It was very well in line with the circuit complexity. 
  3. more noise contribution (this was also a good friend with circuit complexity).

When I looked into the dynamic range of my design, it was not improved that much from that of an ordinary differential pair circuit (even so the paper was published [1] :). Then I got an idea that ‘instead of inventing a sophisticated linearization technique to obtain larger dynamic range, trying to use as less as possible noisy circuit elements and forget about linearization are more reasonable for biomedical signal processing which requires a good deal of power reduction’. The idea was left there since then for two reasons: I had other jobs to do and the idea seemed too sloppy.

Let me tell you more about the mysterious power. Several times we did rehearsals before the ELCA festival. I was in charge of acoustic guitar and harmonica for the song called ‘The end of the world’ Playing two instruments at the same time made me tired and it did not make a good harmony as expected. So I stopped playing the guitar and exercised only the harmonica (of course combined with the piano from Wouter, the electric guitar of Mark and Wannaya’s voice (I could not find this song on our Youtube channel — don’t know why). The song turned out better than before and this reminded me of that sloppy idea!!!

I did an investigation and found that there are strong evidences supporting my idea founded in low-pass filter design [2] [3]… It works!!! Large dynamic range was achieved as well as a very good figure of merit. Although the above filters were dedicated to communication systems rather than for low frequency biomedical signals, the underlying concept of the filter should be applicable for biomedical signal as well. Only a bit more effort was needed to work it out.

Good news!!! Recently, with the help from Senad, who has become 22 years old today — the same as me :). Happy Birthday!!!— my sloppy idea was realized. A 6th-order ECG low-pass filter with a large dynamic range of 59dB and extremely low power consumption of 0.45nW has been designed. We plan to submit this work to BioCAS2011. Hopefully, the reviewers will like it, too.

More good news!!! The application is not limited to low-pass filters only. I’m developing this idea further to apply it for a cochlear channel band-pass filter. What I can say now from the circuit simulations is that the filter provides the best figure of merit compared to state of the art designs. The secret is that all terminals of a single MOSFET device are being used, one pole and one zero are achieved by only two transistors sharing the same bias current.

Next time, I will tell you more about this. Stay tuned if you are interested!!!

Healthy Haring is coming. I heard from Marijn that this year, since the weather is warm, the fish is growing bigger. See you in the Pub this coming Thursday for Harings and Beers 😀


[1] C. Sawigun, D. Pal and A. Demosthenous, “A wide linear range transconductor subthreshold transconductor for sub-Hz filtering,” Proc. IEEE ISCAS, pp.1567-1570, 2010

[2] D. Python, A. S. Porret and C. Enz, “A 1V 5th-order Bessel filter dedicated to digital standard proceses,” Proc. IEEE CICC, pp. 505-508, 1999

[3] S. D’Amico, M. Conta and A. Baschirotto, “A 4.1mW 10MHz fourth-order source-follower-based continuous-time filter with 79-dB DR,” IEEE J. Solid-State Circuits, pp. 2713-2719, Dec. 2006

Donation for the recovery of Japan

The 2011 ELCA music festical will be held on Friday, March 18th, at 19:00 hrs. Last year, it used to be an activity for people to enjoy music after a year of research. This year the theme has changed. While we were preparing for an evening full of fun, a tragedy happened. After the earthquake, Japan has been bruised again by the wave ‘Tsunami’. More than 10,000 people have been swept away. Nuclear reactors are at the verge of exploding. People in that area can hardy find clean food and water.

We cannot not just watch the news and go to bed without worrying about the Japanese people.

Then a discussion arose in our research group. "How can we help?" The result is: we will dedicate our performance at the ELCA festival this year to Japan. The price of the beer will be 10 cent higher. This is for a donation; the money we get from the drinks will go to Japanese people. We know this is not gonna be big money but every Euro counts.

Dear readers, please come to the ELCA festival in the Pub, Mekelweg 4, Delft, at 19:00 hrs. We have prepared a Japanese song for this. 

Each glass that you drink is meaningful. It is the drink of kindness driven from human symphathy inside you.

Let’s sing together for our Japanese friends letting them know that they are not alone.

See you on Friday.



Is darkness only all blind people can see?

Doing research on neural recording & stimulation that are dedicated to recovering human senses, a question like this may come to your mind: "between loss of hearing and vision loss, which one will make me suffer the most"

It’s a difficult question to answer…and for sure noone wants to experience it. But let’s see what famous people say…

Beethoven stated that "….for me there can be no relaxation in human society; no refined conversation, no mutual confidences. I must live quite alone and may creep into society only as often as sheer necessity demands… Such experiences almost made me despair, and I was on the point of putting an end to my life…"

Helen Keller wrote "…I am just as deaf as I’m blind. The problems of deafness are deeper and more complex, if not more important, than those of blindness. Deafness is much worse misfortune. For it means the loss of the most vital stimulus — the sound of the voice that brings language, sets thoughts astir and keeps us in the intellectual company of man." 

Three, my favourite Dutch band 😉 sings in their song ‘Way back from the Hague‘ that "Silence came over me!!!!"   …and " Darkness is all I can see."

Caraboa, the most famous Thai rock band also has a song dedicated to a blind musician called ‘Wanipok‘. In short it says (interpreted by me): ‘when my eyes are covered by darkness, my life is still illuminated… by music.’ 

For me, silence will isolate us from the society and this will lead us to a deep loneliness. Sometimes… just listening to songs, beautiful scenes can occur in our minds. Is the brain playing tricks on us? Or does it imply that losing sense of hearing is more severe than being blind and darkness is not what blind people can only see.

On March 18th, there will be the 2nd ELCA music festival in the EWI student pub Pub, at TUDelft. The Biomedical Group’s band will perform Wanipok, a cover, and many other songs. I really look forward to that 🙂