Hi, I'm newbie in DSP. I have question related to transmit power. My scenario is that I have a set of signal value to be transmitted and I want to have transmit power about 5dBm. How can I set it? Thanks a lot.
Transmit Power
Started by ●October 1, 2007
Reply by ●October 1, 20072007-10-01
Hi, dBm is an absolute power, like in "60 W" bulb. For example, assuming the signal is driving into a 50 ohm load, you'll need to produce a voltage with an RMS average of about 0.4 V over the load. If it's a sinewave, it shows on a scope with peak amplitude of 0.56 V. -mn
Reply by ●October 1, 20072007-10-01
"cau2danang" <sstrong084@yahoo.com> writes:> Hi, > > I'm newbie in DSP. I have question related to transmit power. My > scenario is that I have a set of signal value to be transmitted and I want > to have transmit power about 5dBm. How can I set it? Thanks a lot.You must know the system gain and the load impedance. Do you have that information? -- % Randy Yates % "Bird, on the wing, %% Fuquay-Varina, NC % goes floating by %%% 919-577-9882 % but there's a teardrop in his eye..." %%%% <yates@ieee.org> % 'One Summer Dream', *Face The Music*, ELO http://www.digitalsignallabs.com
Reply by ●October 1, 20072007-10-01
>"cau2danang" <sstrong084@yahoo.com> writes: > >> Hi, >> >> I'm newbie in DSP. I have question related to transmit power. My >> scenario is that I have a set of signal value to be transmitted and Iwant>> to have transmit power about 5dBm. How can I set it? Thanks a lot. > >You must know the system gain and the load impedance. Do you have that >information? >-- >% Randy Yates % "Bird, on the wing, >%% Fuquay-Varina, NC % goes floating by >%%% 919-577-9882 % but there's a teardrop in hiseye...">%%%% <yates@ieee.org> % 'One Summer Dream', *Face The Music*,ELO>http://www.digitalsignallabs.com >Hi. Thx for your reply. Actually I wanna generate short preamble of 802.11a for synch testing. The transmit power of my signal is 5dBm.
Reply by ●October 1, 20072007-10-01
"cau2danang" <sstrong084@yahoo.com> writes:
>Randy Yates wrote:
>> "cau2danang" <sstrong084@yahoo.com> writes:
>>
>>
>>> Hi,
>>>
>>> I'm newbie in DSP. I have question related to transmit power. My
>>>scenario is that I have a set of signal value to be transmitted and
I want
>>>to have transmit power about 5dBm. How can I set it? Thanks a lot.
>>
>>
>> You must know the system gain and the load impedance. Do you have that
>> information?
>
>Hi. Thx for your reply. Actually I wanna generate short preamble of
>802.11a for synch testing. The transmit power of my signal is 5dBm.
You have multiple problems:
1. Look up definitions of "preamble" and dBm (see also "decibel").
[Hint: They are unrelated ;]
2. What does 802.11(all flavors) set out to standardize?
3. Browse unfamiliar terms you encounter.
A suggested exercise:
Write yourself a short paragraph describing what you are attempting.
Imagine you are writing to a relative you haven't seen for a couple of
years. I suspect you'll have some difficult areas. Ask us questions
about those areas.
Reply by ●October 1, 20072007-10-01
cau2danang wrote:> Hi, > > I'm newbie in DSP. I have question related to transmit power. My > scenario is that I have a set of signal value to be transmitted and I want > to have transmit power about 5dBm. How can I set it? Thanks a lot.An analogy to this question is to ask what seed you should plant in your wheat field to allow you to build a second story on your house* -- you're asking questions from two different domains. DSP involves manipulating numbers in mathemagic** land, and therefore has no direct bearing on the power level of anything. To get to a power level, you have to understand what the numbers are doing to the physical world (presumably via a DAC and a big amplifier chain). * Well, if it weren't for the DEA I could answer that... ** "Donald Duck in Mathemagic Land", Disney, 1957. It's available on DVD now -- we just got a copy, and it inspired the 9-year-old to an evening of mathematical experimentation with twanging rubber bands. Fun stuff. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●October 1, 20072007-10-01
Tim Wescott wrote: (snip)> ** "Donald Duck in Mathemagic Land", Disney, 1957. It's available on > DVD now -- we just got a copy, and it inspired the 9-year-old to an > evening of mathematical experimentation with twanging rubber bands. Fun > stuff.There are two movies I still remember from elementary school days. The one above, and "Hemo the magnificent". One web site seems to say that Donald is from 1959, but our library doesn't have it yet. It does have Hemo, which I borrowed a few years ago. -- glen
Reply by ●October 1, 20072007-10-01
glen herrmannsfeldt wrote:> Tim Wescott wrote: > > (snip) > >> ** "Donald Duck in Mathemagic Land", Disney, 1957. It's available on >> DVD now -- we just got a copy, and it inspired the 9-year-old to an >> evening of mathematical experimentation with twanging rubber bands. >> Fun stuff. > > There are two movies I still remember from elementary school days. > > The one above, and "Hemo the magnificent". > > One web site seems to say that Donald is from 1959, but our > library doesn't have it yet. It does have Hemo, which I borrowed > a few years ago. >I go on-site to one of my clients quite frequently. I'm thinking of bringing the DVD along for some lunch-time entertainment for the engineering department. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●October 4, 20072007-10-04
On Mon, 01 Oct 2007 09:39:04 -0700, Tim Wescott <tim@seemywebsite.com> wrote: (snipped)> >** "Donald Duck in Mathemagic Land", Disney, 1957. It's available on >DVD now -- we just got a copy, and it inspired the 9-year-old to an >evening of mathematical experimentation with twanging rubber bands. Fun >stuff.Hi, Sometimes DSP causes my to sit on the floor and mindlessly twang rubber bands. [-Rick-]
