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The title: Flash Bandwidth 1KHz to 100MHz
The title: Flash Bandwidth 1KHz to 100MHz
Digital Controlled Broadband
Anti-alias & Reconstruction Filter
Dear Sir: This is my discussion article.
The details:
http://www.cnindex.net/~tjsh/Base_of_Broadband_Access.html
http://www.cnindex.net/~tjsh/Base_of_Broadband_Access.doc
Sincerely,
Robert Tan
11.22
Flash Bandwidth 1KHz to 100MHz
Digital Controlled Broadband
Anti-alias & Reconstruction Filter
The Next Era Web of Multimedia Data-stream
Transmission Solution of the Internet!
By Robert Tan
Update: 1999. 11. 22
For the many more format and definite of standard of digital film and
video, digital audio
and the other multimedia data stream of tomorrow, the existing network
technology including
the modern internet webs will be fabulous and difficult to transmit it
for us. The Endpoint
Congestion almost resistant our viewer area full of the entire world, We
would need the
straightway link of the multi-media data-stream in real-time for us.
Would you like to get a lower cost & more effective digital signal
channel in a wide-bandwidth
or broadband hybrid coax cable system? For the FTTX, HFC networks,
especially in the HFC
networks with the 256QAM or 64VSB digital modulation technology systems,
the SSB-ASK or the
VSB-ASK technology transmission systems would be used normally. The
Flash Bandwidth 1KHZ to
100MHz digital control a variable frequency bandwidth, it is
high-performance anti-alias &
reconstruction (FBW) filter, it will be able to provide a variable
multiplex sub-frequency
band in any broadband HFC system. With the FDM assistant digital carry
system and SSB or VSB
signal channel, a group of FBW filters will provide separate
multi-frequency bands in spectrum
without any cross talking and distortion by a large frequency range in a
high-speed high-
effective transmission system. In a FTTX or HFC web, this digital
controlled signal channel
would have a very large frequency spectrum changed dynamic range. For a
large client group,
such as the Broadband Cable Internet Access or HFC users, one of them
would like to get a
variable data speed according to the applications of his needed. It will
provide a lot of
digital control frequency bandwidth which is separated one another in
HFC transmission system,
and it will more effective for the "hot clients", such as the VOD video
clients or the other
high-code rate users and high-speed data stream user's applications. The
FBW will improve the
speed of the data stream, diminish the amount of the spare resource
seizing of "Cool Clients",
reduce the calculations of the DSP processor of the center web main
switching system and the
branch switching system. Reduce the CPU utilities of the applications in
all of client
communication adapter and its cost of produce is very important. The
"Cool Clients" mains
the IP telephone users or the other lower speed code rate audio
applications. Anyway, the
speed of the up-stream data and down-stream data speed could be changed
to any value you
needed, and the changing degree will be very smoothly and very simply in
writing one or
two bytes in the command system of communication web switcher. By the
high-speed frequency
variable characteristic, if the FBW filter were used in your FTTX or HFC
switching system,
the upward and downward data stream speed could be managed and attempted
by your command
system. So that, the transmission bandwidth will be able to adjusted to
your needed in any
time within one millionth second. The real-time will be very more
improved and more effective
on the communication main roads such as FTTX and HFC system,
transmission controlling system
will completely control the data stream in real-time.
Dear Technology Research and Development Administrator:
I am an electronic engineer in the field of Analog and Digital
filters researching and
designing. I had been a DSP engineer for ten years. My development field
is electronic circuits
-- digital and analog hardware designing and researching in applications
of Digital Signal
Processing. My works contains the frequency spectrum analysis, digital
audio and digital video
systems, noise spectrum controlling and processing, and the other
military applications. I have
researched and designed several kind of analog and digital anti-alias &
reconstruction filters.
A few years before, in my R&D works, I find the special frequency of the
filters is usually
fixed, it could be very difficult to change the cutoff frequency of the
low-pass anti-alias
& reconstruction filter. But the fixed filter could not suit the target
of my technical
applications. If we want to get several special frequency of the
filters, we must to use
several different fixed filters or instead of fixed filter with
switching capacity filter
or digital filter, such as IIR or FIR filter, and their frequency must
be variable in order
to change the analysis frequency. It is very important for the spectrum
analysis system and
the digital random real time vibrated controlling system. But, in this
way, we must pay for
digital IIR or FIR filter, it is very expensive in the price, take a
large space for the DSP
chips and its outside memory banks to install it. So, we would get into
much troubles and
complex questions from a simple problem.
However, we have the switching capacity technologies, and the product of
up to 8th order
filters is a very normally used. But the switching capacity filter will
have a high noise
and low frequency range, and it has a non-exactly special frequency,
generally. The special
frequency of most of the switching capacity filters is from 1/95 to
1/105 times of its main
switching clock and it is difficult to improve its accuracy. Actually,
the switching capacity
filter circuit is very difficult to adjust and use in applications.
Anywise, its order is
normally below 8th order, and the special frequency and bandwidth of the
switching capacity
filters is below to 50KHz, and the amplitude response is not exactly
yet, the dynamic range
of the amplitude is very low, normally, it is below the 48dB. Except of
frequency range from
0 to 50Hz, in this field, its dynamic range is lower than 30 dB and not
usefully, it is
normally being used in the speech processing circuit and the other lower
frequency band
processing systems. Attention, all of this analysis is not including the
phase noise of the
main switching clock and the noise of clock feed through yet. The
others, it is difficult to
get much more analysis frequency bands or special frequency points for
the switching capacity
filters, it is especially for the higher frequency band which is
approached to the top
frequency point. All of these characteristics of the switching capacity
filters will restrict
its applications in the area of modern digital communications.
The others method of the filters designing is the contact-time analog
filter .I have found
some method. It could make many transfer functions. Such as the
elliptical function,
Chebyshev function and Butterworth function, but there is some
interesting things here,
it is that the same circuit frame could be built into many transfer
functions, and it
would have programmable (digital controlled) special frequency. Changing
special frequency
on line is available. It could get the very wide frequency range, very
quickly to change
the used band, and the digital controlled circuit is very directly and
simply, the special
frequency step is very smoothly (because the Frequency is controlled by
long bit Digital
multiplier). In that points, integrate the FBW filter circuit technology
is very useful
for the digital controlling and processing systems. Because of the
Digital Controlling
Flash Bandwidth Filer (FBW) is depend on a few chips of high quality 8
or 12 bits long
Digital Multiplier and a few chips of high-speed amplifiers. The other,
this filter
technology is used with a few exactitude resistors and exactitude
capacitors also. For
example, an 8th order elliptical filter need 8chips of dual Digital
Multiplier and several
chips high bandwidth amplifiers, 8chips exactitude capacitors and
several chips exactitude
resisters. If it is possible, integrating all the Digital Multiplier and
amplifiers into
one chip or one plastic package (mixed circuit), place all the
exactitude resistors and
capacitors out of the package. It will be finest filter and very easy to
used and could
be re-designed agilely by the customers and the OEMs. The parameter of
the filters is
depending on the value of the resistors and the capacitors. Its value
could be designed
by the customs freely and calculated by constant functions directly, and
that is very
simply.
And then, the FBW filters would be very usefully in the FTTX or HFC
networks. For working
with the 256QAM or 64VSB modulation technology and any narrow-band
transmission technology
systems, such as the Broadband Cable Internet Access webs, HDTV or SDTV
and VOD systems, it
would compress the used frequency bandwidth in mostly extent. Because of
the WAN systems in
any nations will be depending on the "Tree structures" as the main road
in the webs in the
future. The frequency source is very expensive in this web, It would be
welcomed in the
Internet web digital information transmission, exchanging and switching
technology area,
DSP area and digital communications area, such as MAN and WAN coax cable
webs or the FTTX
system applications. Any way, the most of modern networking transmission
mode is TDM. It
is very suitable for the text material or media, because of it is a
fixed media in size,
and it is the fixed continue time in length and generation procedure.
But the most of
multimedia is not to be suitable with that. The data stream of voice and
video will have
no constant size to be forecasted has no constant procedure time. It is
only have a constant
and fixed bandwidth of media data stream. Because of your interesting
points is onto the
generations and the procedures of the video or audio information of thus
material or the
news, such as the high quality digital cinema, digital musicale and so
on. Certainly, you
could take the any multimedia information and any moving picture on you
desktop through the
Internet Web. It will be appeared the true alive world with you in any
site you can go! So
that, the only one of best way of the media data streams transmission
and exchanging is the
FDM mode with the SSB-ASK or VSB-ASK technology, it should be working
with the QAM or
VSB- ASK digital modulation technology in the future Internet webs.
FBW filter would be used in most of switchers and routers, which is
depending on the FDM
technologies. For the cable TV systems STB (set top box), video & audio
servers in Broadband
Cable Internet Access, cable modems or the client-end adapters in the
most of family users
and the most of business cable users in the world will need a very great
deal of broadband
web transmission bandwidth. Because of that, in any modern
home-electronic equipment, such
as the Internet officers, shopping's and the VOD or the other broadband
information
electronics, its using method would be depending on the FDM switching
technologies. So that,
the "Online Home-Electronics" or the other Internet accessing products
which is used in
people's homes would be simply to operate and easy to use. And it must
be depend on the
simply low-layer hardware equipment and protocols of the webs, such as
the VOD systems
and the STB terminals in the Broadband Cable Internet Access or HFC
networks. The FBW
technology would provide us more applicable and useable method in the
physics layer of
the public HFC networks, its FDM applications in a broadband web get us
in a lower building
price, more effective than the other technology. Such as the Broadband
Cable Internet Access
webs, HFC networks, FTTX networks, and the other and the other WAN
public broadband networks
would have a very great applications of the FBW filters.
The others, using a Flash-Band-width filter will help you get in to a
fully data stream
bandwidth management of any expensive data-link channels and the very
expensive communication
data stream bandwidth, such as the communication data-link of the
satellite communication
systems, and the ocean bottom communication systems. FBW filter will
control the any leased
data-stream bandwidth in dynamic mode within a very large frequency
range, a large range of
signal frequency bandwidth and data-stream speed in any time for a
communication administration
and operation system. It will change the bandwidth with you leased data
stream very imminently
within several microsecond, improve your expensive bandwidth of
data-stream transmission channel,
save your leased payment and money cost for any customers of digital
communications and any
Tele-communication operating and service company. It will hold any
important transmission of
data-stream in smoothly and take it freely. So, in this system, any
interrupt of your
communication data stream will be never.
The Digital Control Flash Bandwidth Filter specifications:
(1) General details:
Frequency range: 0.1Hz--100MHz
Useable frequency range: 0.1Hz--100MHz(at least)
Special frequency step: 0.001Hz-1000KHz
Transfer functions: Elliptical, Butterworth, Chebyshev, and Bassel
function.
And the others contacted-time filters.
Available filter type: Low-pass filter, High-pass filter, Notch filter,
Band-pass filter and All-pass filter.
Noise Level: -160dB(max) (Only depend on the number of the used
amplifiers.)
Order range: 2nd--12th(Depend on the sensitivity of the transfer
functions.)
Filter switching time: Less than 300nS (Filter Setting time is 200nS)
Useful Range: Anti-alias filters, Reconstruction filters.
(2) Pass Band Specifications:
Frequency selectable range: 100Hz--100MHz
(Depend on the performance of the selected amplifiers)
Special Frequency steps: 1Hz-1000KHz
Pass band Dynamic range: 90dB (Depend on the amplifiers and the order of
the filter.)
Ripple: 0.01--1.0dB (Only depend on the filter function and the
passband ripple designed.)
(3) Pass to Stop Band:
Drop speed of Interim-band Cut-off:
180db/oct (8th order elliptical function with 0.05dB pass-band ripple)
(4) Stop Band:
Amplitude min drop: 120db(8th elliptical filter for example)
Frequency range: 0.1Hz--100MHz
(Depend on the amplifiers and the Digital Multiplier specifications)
(5) Digital Control specifications:
Digital component is used (8 bit, 10bit, 12bit, and 16bit is available).
The special frequency is (N1/N2) * Frequency (ref).
(The N1, N2 is the Digital component input byte, from 8bit to 16 bit.)
The Frequency (ref) is form 10Hz to 10MHz.
(This parameter is depends on one RC time constant.)
High speed and voltage feedback high-bandwidth operation amplifiers are
required.
(6) Requirement: (The filter section of 8th order)
Digital component: 8 chips (Selections depend on the frequency range)
High-performance Amplifiers: 12 to 24 chips (Selections depend on the
frequency)
Capacitors or inductors: 8 chips (exactitude degree value is 1% to
0.1%)
Resistors: 16-36 chips (exactitude degree value is 1% to 0.1%)
(7) Group delay: Depend on the function of the filter
designed, filter
phase response designed, and the filter
order.
(8) Filter switching time: Less than 300nS (Filter Setting time is
200nS)
The Comparisons of the 4 kinds active Filters
For example:
8th order filter
Switching Capacity Filter
Digital Filter
(FIR or IIR Filter)
Traditional
Fixed Analog Frequency Filter
Digital controlling FBW filter
Noise Level or (THD+N) Value:
Highest
-48db
Lower
-70db
Very Low
-160db
Very Low
-120db
Filter Dynamic Range
The Value:
Little
50db
Middle
70db
Very Large
160db
Large
100db
Real-time active frequency
The range of the value:
Narrow
200Hz to 300KHz
Wide
0.001Hz to 50KHz
Very Wide
0.1Hz to 1MHz
Very wide
0.001Hz to 100MHz
The Outside in advance Anti-alias & Reconstruction assistant filter
requirement
The degree of assistant filter Quality
Required
2nd to 4th order anti-alias & reconstruction assistant outside filter
Required
4th to 6th order anti-alias & reconstruction assistant outside filter
Not required.
----------
Not required
----------
The Precision of the special frequency:
The ability of on-line changing the filter special frequency
&Method
Low.
+/-3%
Very easy
(Changing the switching clock)
High
+/-3%
Very difficult
(Change a new programs and
parameters )
Very high
0.1%
Very difficult.
(Changing the system time
constant)
Very high
0.1%
Easy(Writing digital word to the filter control port)
The complex degree of the filter system designing
&The used space
Simple
Small
Very complex
Very large
Simple
Middle
Middle
Middle
The price for produce a filter
&The difficult degree of the applications
Very low
$10~50
Easy
Very high
$300~600
Difficult
Low
$30~90
Easy
Middle
$50~100
Middle
Anti-alias & Reconstruction filter Performance: (1)Pass Band
Ripple &Dynamic Range:
(2)Stop Band
Rejection
(3)Interim Band Dropping Slope:
Low Quality & Low Price.
+/-0.2db
50db
55db
50db/oct
Normal or High Quality & High price
+/-0.01db
70db
70db
130db/oct
Normal Quality & Low Price
+/-0.01db
120db
120db
180db/oct
High Quality & & Middle Price.
+/-0.01db
110db
120db
180db/oct
Online/offline Changing of highest/lowest special frequency rate &
Range:
&changing time:
All available
1000 times
300Hz to 300KHz
10mS(Time of PLL tracking & locked)
Offline available
Not available
Not available
Not available
(Reboot DSP & A/D system)
Offline available
1000 times
Not available
Not available
All available
100000 times
1KHz to 100MHz
160nS (TTL 2 bytes writing time)
Filter online reconstruction setting time (The total time of
filter frequency switched)
10mS
Not available
Not available
300nS
Group delay and the phase response:
Producer design only.
Linear or Producer design only.
Producer design only.
Producer & User design is available.
Equality data stream speed or comported speed of its TxDAC :
&Butterworth 8th filter
(Broadband channel HFC usable signal dynamic range is about 50dB):
4.8Kbps to 4.8Mbps
(600SPS to 600KSPS)
8bit TxDAC
Constant 400Kbps
(50KSPS)
8bit TxDAC
Constant 800Mbps
(100MSPS)
8bit TxDAC
16Kbps to 1600Mbps
(2KSPS to 200MSPS)
8bit TxDAC
Suitable with the 8bit TxDAC and used 256QAM (or 64VSB) in SSB/VSB mode
of technology
(Data speed of Base Band):
Carrier signal RF full-band tie up:
Difficult to be used with the 256QAM and 64VSB.
(High Level Phase Noise)
4.8Kbps(Min)
4.8Mbps(Max)
384Hz to 384KHz
Difficult to be used in variable data-speed transmission or receiving
system
Difficult to be used in variable data-speed transmission or receiving
system
With 256QAM:
8Kbps(Min)
800Mbps
(Max)
With 64VSB:
12Kbps(Min)
1200Mbps (Max).
1.28KHz to 128MHz
For the HFC Specialty signal TV Channel:
40dB Eb/N
6MHz Full-band 64VSB model
@1KHz-6MHz
Data-rate:
With 64VSB:
9.375Kbps
(Min)
56.25Mbps
(Max)
Contact Address:
No.2 Buliding Room1007,
Mudanyuan Beili, Haidian District
Beijing P. R. China,
Post Code: 100083
Name: Tan Junsheng (Robert Tan)
Tele: 8610-82076834, 86-13701070213(Mobile)
E-mail: Tjsh@netchina.com.cn or tanjun@hotmail.com
Homepage: http://www.cnindex.net/~tjsh
Details Remind:
http://www.cnindex.net/~tjsh/Base_of_Broadband_Access.html