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Old 19th November 2008, 07:52 PM   #11
Gyula is offline Gyula  Hungary
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The output feedback was from the output of the demodulation filter, directly from the output terminals. The PSV feedforward measured the power supply voltage directly. Of course there were many feedback loops in the FPGA signal processing as well. For example in the Smith-Predictor and Noise Shaper. And in every integrator of the CIC filters, and inside the DCMs and even in the 2-DOF controller filter... ...and outside of it every op. apm. were fed-back on the board .
It was also stable unoaded.
The utilization of the XC3S400 FPGA was about 96 % of Slices and 16 pieces of dedicated multipliers and worked with 99 MHz clock frequency. The signal processing was 36-bit wide up to the Noise Shaper. We originally built a simpler one with György Dancsi for the SSC last year autumn. I used the FIR interpolators from that what Gyuri made, and the 2-DOF controller, and developed new blocks with the written thesis in 2.5 weeks. That was a very hard deadline. I made that on Géza Balázs and Tibor Kimpián's FPGA board what they made for a loudspeaker cone velocity feedback amplifier project for the SSC in 2005. At this time it's in the Acoustical Laboratory of Building I.
The board contains one more ADS8422. We are planning to expand the control with cone velocity feedback for this amp as well.

P.S.: I forgot to mention that there's a mistake in Post #9. Not the absolute sum of the NS filter's coefficients represents the power gain but the squared sum, according to the Parseval-theorem. But it doesn't matter for the understanding because the square and the absolute value of first coefficient are always equal to 1. So the sum will always be larger than 1.
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Old 20th November 2008, 07:43 AM   #12
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For wich process did you use the smith predictor? How much was the delay?
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Old 20th November 2008, 07:59 AM   #13
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That was used because of the linearizer filter. The delay was 3 clock cycles and the sample rate was 99 MHz/256 but the linearizer filter interpolated the audio up to 99 MHz for PWM comparation.
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Old 20th November 2008, 10:20 AM   #14
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OK, but what was the controlled process? It mustn't be only a linearizer filter.
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Old 20th November 2008, 11:02 AM   #15
Gyula is offline Gyula  Hungary
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The controlled process comprised the output and the feedback as well. A part of them is personal confidential data .
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Old 20th November 2008, 03:44 PM   #16
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Ezt direkt csinálod?
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Old 20th November 2008, 05:47 PM   #17
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Nem. A harmonikus kiejtes amit hasznaltam szerintem meg nem jelent meg irodalomban, ezert nem akarom leirni. Utana akarok nezni hogyan lehetne szabadalmaztatni.
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Old 20th November 2008, 09:05 PM   #18
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Akkor azt ne írd le! Vagy ha leírnád, hogy a smith prediktort milyen szabályzási körbe tetted, abból kiderülne a találmányod lényege? Ha így van, akkor simán megírhattad volna elsőre is, hogy nem publikus, a látszatválaszok helyett.
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Old 21st November 2008, 05:25 PM   #19
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Hi Pafi!

This is an English forum. Please keep it in respect. I wouldn't like to describe the whole control loop because I think it's unique. But I will do it as I can.
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Old 21st November 2008, 06:05 PM   #20
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Gyula!

I'm sorry for having broke the forum's rule, but when I asked you in English, i didn't see the answer was really referred to my question.

Quote:
I wouldn't like to describe the whole control loop
I didn't ask you to do this.

Quote:
But I will do it as I can
Thank you!
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