HUYGENS MCD
TECHNOLOGY

What's
the MCD?

MCD stands for
"MHz Class-D", A new amplifier technology from John.Fu(Fumac)
and Zhaolian.Fu. This New Class D amplifier
technology runs a very high sampling rate Frequency (from around 700KHz~2.6Mhz, at a fixed frequency). This technology
enables us to produce amplifiers of high power(up to 800w), Low THD(0.00x%),
Low phase-shift, and a Class A like sound all from a compact, cool running,
environmentally friendly design, perfect for a HiFi,
AV system, active speaker or professional amplifier.

MCD amplifiers feature two feedback paths (Figure 1), one to produce the High
Frequency oscillation frequency, the other for AF error feedback,
this AF feedback includes the output filter to ensure load independent
performance. By combining these two loops, you can create a system with both
outstanding technical and subjective performance.

AF
Error Feelback , Low THD

MCD has an AF error feedback from the speaker terminal , this feedback can fix
the large THD from the filter , so MCD can get a very low THD also at very high
power output. Figure 5: samples of THD in high power output .

THD spectrum analyzer of MCD-300 at 2W 6ohm,

THD=0.0035%(-87db) at 1k ,THD=0.0100%(-80db) at 7k ,THD=0.0112%(-79db) at 15k

THD spectrum analyzer of MCD-300 at 100W(rms) 6ohm,

THD=0.016%(-76db) at 100Hz ,THD=0.012%(-78db) at 1k ,THD=0.016%(-74.5db) at 7k

The Higher The Sample Frequency , The More Detail

Previous Class D technology ran below 100KHz. This is not quick enough for
full-range (10Hz~20KHz) audio performance, and can
only be consider suitable for subwoofer (10Hz to 250Hz) applications.

More recently Class D designers have been able to increase the switching
frequency of their designs to 200k~250k. These type of
Class D amplifiers can produce close to full range audio (about 10hz ~18KHz).
Typically these designs had great bass but poor treble. Still these amplifiers
have found homes in AV systems, sub woofers, and Mid Fi
applications. Figure 2 show level error at different speed of damp.

Bringing us up to date, there are some very good designs that now run at
between 350¨C400KHz. These are the first designs that can reproduce the
accepted "full bandwidth" (10Hz~22kHz) with finesse
. However, the phase shift between bass and treble is to
great to produce a fully cohesive sound. (Figure 3)..

High Frequency, Low Phase-shift, Low EMI

MCD runs at speeds of between 700KHz to 2.6MHz (up to 6 times faster then the
current state of the art), It has an extended audio bandwidth from below 1Hz to
beyond 60KHz with a simple filter (80KHz Low Pass Filter), as the high
switching speed makes this possible.

Looking at he picture(Figure 3 and Figure 4), the MCD
generates lower EMI, has less phase shift and has a greater bandwidth than
other D Class amplifiers. With a AF error feedback,
the phase shift can be zero.

Balance
response

A Butterworth filter is inside most of HIFI class-d amps, this is make the
lowest EMI of damp, make it work well with others.

Some old class-d amp have a 3V carrier frequency output(about
280mW, like a ).Class-d amp running in 400k have 0.8V(about 20mW to 4ohm, like
the output power of wireless microphone) . Through the speaker line, it will
transmit to anywhere. MCD just have less than 0.1V(about
0.3mW ) carrier frequency output. It's very lower than the others.

A simple filter can't make the balance with audio frequency flag
, low phase shift and lowest carrier frequency output, except the
carrier frequency far away from the audioband. But
MCD can, because the very high frequency(700k~2.65MHz).(Figure 3 Figure 4 )

Active
loads

Speakers have different loads, a 4ohm speaker some times between 2ohm to 8ohm,
sometimes we use a same AMP to drive different speakers, this is call active
load character.

The simple filter of class-d amp response like Figure 5 ,
we found that the treble will different in the different load.

Figure 6 shows the active load character include 400k class-d amp and MCD, we
found that the MCD have a more flag response than the 400K class-d amp (13.7dB
VS 7.5dB from 1ohm to 16ohm) . This is meaning MCD can driver different load
with a same-like response.

MCD with a very strong current output, most types of MCD can driver 1ohm load.

15
Years Experience, offer customs design

John.Fu and ChaoLian.Fu are
the designer of MCD . They have Experience working in
RF design and AF design for 15 years, Good at super high speed PCB design and
Hi-FI audio design. This make the MCD work in very high
performance. We offer our designs to other companies for Custom design all
around the world.

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copy right: john.fu zhaolian.fu
2006~2007

email: [email-masked] (skype)

website: www.class-d.net