Filter design for a communication system in 0-60Mhz

I am working on a powerline communication system where i need to upconvert
in 28-56Mhz range and later downconvert it to 0-28Mhz so that it works in
the coupler range.So i need to design a band pass filter in 28-56Mhz and a
low pass filter in the 0-28Mhz range. I need to design an analog filter for
the same. I have no experience of filter design. I have been looking online
for resources but wherever i go there is an explanation on chebyshev,
butterworth and elliptic filters.Then you have 1st order,2nd order and
higher order filters equations. My problem is from all this i am unable to
decide which type of filter to use and what order to use. So i need to
understand practical design constraints and examples of how to design given
certain constraints and then boiling down to a solution. So could anybody
help me in how to approach the filter design problem and suggest either
examples or resources to go forward. 

	 

_____________________________		
Posted through www.DSPRelated.com

On Wednesday, August 21, 2013 9:53:03 PM UTC-4, talasila wrote:
> I am working on a powerline communication system where i need to upconvert
> 
> in 28-56Mhz range and later downconvert it to 0-28Mhz so that it works in
> 
> the coupler range.So i need to design a band pass filter in 28-56Mhz and a
> 
> low pass filter in the 0-28Mhz range. I need to design an analog filter for
> 
> the same. I have no experience of filter design. I have been looking online
> 
> for resources but wherever i go there is an explanation on chebyshev,
> 
> butterworth and elliptic filters.Then you have 1st order,2nd order and
> 
> higher order filters equations. My problem is from all this i am unable to
> 
> decide which type of filter to use and what order to use. So i need to
> 
> understand practical design constraints and examples of how to design given
> 
> certain constraints and then boiling down to a solution. So could anybody
> 
> help me in how to approach the filter design problem and suggest either
> 
> examples or resources to go forward. 
> 
> 
> 
> 	 
> 
> 
> 
> _____________________________		
> 
> Posted through www.DSPRelated.com

Are you familiar with heterodyning and radio design? To determine the filter (type, order, rejection etc), you need to spec your system. What are the signal levels? What are your source and load impedances? How much out of band rejection do you need? Are you going to have the 28MHz carrier present so you can do synchronous modulation, demodulation? Your project has a lot of questions - the more you have already answered, the easier it will be for someone to help.

IHTH,
Clay

"talasila" <98371@dsprelated> writes:

> I am working on a powerline communication system where i need to upconvert
> in 28-56Mhz range and later downconvert it to 0-28Mhz so that it works in
> the coupler range.So i need to design a band pass filter in 28-56Mhz and a
> low pass filter in the 0-28Mhz range. I need to design an analog filter for
> the same. I have no experience of filter design. I have been looking online
> for resources but wherever i go there is an explanation on chebyshev,
> butterworth and elliptic filters.Then you have 1st order,2nd order and
> higher order filters equations. My problem is from all this i am unable to
> decide which type of filter to use and what order to use. So i need to
> understand practical design constraints and examples of how to design given
> certain constraints and then boiling down to a solution. So could anybody
> help me in how to approach the filter design problem and suggest either
> examples or resources to go forward. 

You're reinventing the wheel. TI has already done a ton of work in this
area.
-- 
Randy Yates
Digital Signal Labs
http://www.digitalsignallabs.com

On 22.8.13 4:53 , talasila wrote:
> I am working on a powerline communication system where i need to upconvert
> in 28-56Mhz range and later downconvert it to 0-28Mhz so that it works in
> the coupler range.So i need to design a band pass filter in 28-56Mhz and a
> low pass filter in the 0-28Mhz range. I need to design an analog filter for
> the same. I have no experience of filter design. I have been looking online
> for resources but wherever i go there is an explanation on chebyshev,
> butterworth and elliptic filters.Then you have 1st order,2nd order and
> higher order filters equations. My problem is from all this i am unable to
> decide which type of filter to use and what order to use. So i need to
> understand practical design constraints and examples of how to design given
> certain constraints and then boiling down to a solution. So could anybody
> help me in how to approach the filter design problem and suggest either
> examples or resources to go forward.
>
> 	
>
> _____________________________		
> Posted through www.DSPRelated.com
>

Forget it.

If you're attempting to transfer those HF/VHF signals in normal 
household wiring, it won't work. To make it work, you should change the 
wiring to CAT6, but it is not good for power. Feeding HF signals to 
normal household wiring will create an illegal radio station, radiating 
the crud to outside and receiving everyting from outside. Besides, the 
attenuation of normal powerline cable insulation on those frequencies is 
much more than you would like.

-- 

Tauno Voipio

>On 22.8.13 4:53 , talasila wrote:
>> I am working on a powerline communication system where i need to
upconvert
>> in 28-56Mhz range and later downconvert it to 0-28Mhz so that it works
in
>> the coupler range.So i need to design a band pass filter in 28-56Mhz and
a
>> low pass filter in the 0-28Mhz range. I need to design an analog filter
for
>> the same. I have no experience of filter design. I have been looking
online
>> for resources but wherever i go there is an explanation on chebyshev,
>> butterworth and elliptic filters.Then you have 1st order,2nd order and
>> higher order filters equations. My problem is from all this i am unable
to
>> decide which type of filter to use and what order to use. So i need to
>> understand practical design constraints and examples of how to design
given
>> certain constraints and then boiling down to a solution. So could
anybody
>> help me in how to approach the filter design problem and suggest either
>> examples or resources to go forward.
>>
>> 	
>>@Tauno vaipio  I am not transmitting on household cable. we are
transmitting over a stinger cable which can also take communication
signals. we have run those experiments and also checked power level to meet
FCC specs.
>> _____________________________		
>> Posted through www.DSPRelated.com
>>
>
>Forget it.
>
>If you're attempting to transfer those HF/VHF signals in normal 
>household wiring, it won't work. To make it work, you should change the 
>wiring to CAT6, but it is not good for power. Feeding HF signals to 
>normal household wiring will create an illegal radio station, radiating 
>the crud to outside and receiving everyting from outside. Besides, the 
>attenuation of normal powerline cable insulation on those frequencies is 
>much more than you would like.
>
>-- 
>
>Tauno Voipio
>
>	 

_____________________________		
Posted through www.DSPRelated.com

>"talasila" <98371@dsprelated> writes:
>
>> I am working on a powerline communication system where i need to
upconvert
>> in 28-56Mhz range and later downconvert it to 0-28Mhz so that it works
in
>> the coupler range.So i need to design a band pass filter in 28-56Mhz and
a
>> low pass filter in the 0-28Mhz range. I need to design an analog filter
for
>> the same. I have no experience of filter design. I have been looking
online
>> for resources but wherever i go there is an explanation on chebyshev,
>> butterworth and elliptic filters.Then you have 1st order,2nd order and
>> higher order filters equations. My problem is from all this i am unable
to
>> decide which type of filter to use and what order to use. So i need to
>> understand practical design constraints and examples of how to design
given
>> certain constraints and then boiling down to a solution. So could
anybody
>> help me in how to approach the filter design problem and suggest either
>> examples or resources to go forward. 
>
>You're reinventing the wheel. TI has already done a ton of work in this
>area.
>-- @Randy Yates. Do TI have band pass filters IC's in this range? 
@clay  I am using a kind of direct conversion architecture. I am taking two
modems which can transmit and receive. The bandwidth that they work is from
0-28Mhz. so i am transmitting one signal from 0-28Mhz and another signal
through  second modem from 0-28Mhz and then upconverting it to 28-56Mhz
frequency using an upconverter. Then at the receiver I downconvert one of
the modem's signal from 28-56Mhz  to 0-28Mhz and send it inside the modem
which does the demodulation. so i need to use an upconverter and
downconverter for the second modem and hence my need to design an analog
bandpass filter. From this spec i am unsure of how much passband ripple i
can tolerate, phase margin and other information needed to design a filter.

>Randy Yates
>Digital Signal Labs
>http://www.digitalsignallabs.com
>	 

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"talasila" <98371@dsprelated> writes:
> [...]
>>-- @Randy Yates. Do TI have band pass filters IC's in this range? 

I haven't looked. I know they have an entire product line, their Smart
Meters, thato solves the problem. They may have commercialized some of
that line's components, but I haven't researched it. Check their site.
-- 
Randy Yates
Digital Signal Labs
http://www.digitalsignallabs.com

to the OP

find an ARRL Handbook for Radio Amateurs for a tutorial on analog filters and all things RF.

also "RF Circuit Design" handbook by Bowick


after that find a copy of Zverev.

Mark

On Thu, 22 Aug 2013 06:49:47 -0700, makolber wrote:

> to the OP
> 
> find an ARRL Handbook for Radio Amateurs for a tutorial on analog
> filters and all things RF.
> 
> also "RF Circuit Design" handbook by Bowick
> 
> 
> after that find a copy of Zverev.
> 
> Mark

I second that.  I see all sorts of difficulties with the OP's scheme, but 
his question at least can be answered by looking up filters in the ARRL 
Handbook.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On 22.8.13 7:39 , Tim Wescott wrote:
> On Thu, 22 Aug 2013 06:49:47 -0700, makolber wrote:
>
>> to the OP
>>
>> find an ARRL Handbook for Radio Amateurs for a tutorial on analog
>> filters and all things RF.
>>
>> also "RF Circuit Design" handbook by Bowick
>>
>>
>> after that find a copy of Zverev.
>>
>> Mark
>
> I second that.  I see all sorts of difficulties with the OP's scheme, but
> his question at least can be answered by looking up filters in the ARRL
> Handbook.
>

Me too. It would also be useful to read the chapters about transmission 
lines.

-- 

Tauno Voipio