DSPRelated.com

Average Power

Started by HardySpicer in comp.dsp17 years ago 16 replies

Ok suppose we have an R-C network - low pass filter with tf G(s)=1/(1+sT) where T=CR. We can easily calculate the output power spectrum if...

Ok suppose we have an R-C network - low pass filter with tf G(s)=1/(1+sT) where T=CR. We can easily calculate the output power spectrum if this is driven by zero-mean white noise as Phiyy(w)=mag(G(jw))^2 x power of input noise and the area under the PSD is the total average power. Now let's do the same thing digitally...and produce an equivalent digital filter G(z) The output p...


How power analyzer works for high input frequencies

Started by Korenje in comp.dsp14 years ago 3 replies

Hi everybody! As DSP is not really my field I have a question that bothers me and I think someone here has enough experience to at least...

Hi everybody! As DSP is not really my field I have a question that bothers me and I think someone here has enough experience to at least nudge me in the right direction. In my field I frequently use power analyzer to measure RMS (square root of sum of squares) values of voltage and current. Basically I measure power of a signal. From power analyzer specs I know it has sampling frequen...


controlling signal power

Started by manishp in comp.dsp11 years ago 3 replies

Sirs, I have read in some of the wireless literatures that certain data are deliberately transmitted with higher power. However, I dont...

Sirs, I have read in some of the wireless literatures that certain data are deliberately transmitted with higher power. However, I dont understand what increasing the signal power means and where exactly happens. Does increasing power means simoly increasing the amplitude and in case of wireless applications, does this happen in RF section of the transmission Thanks, manish


reactive power....

Started by fisico32 in comp.dsp14 years ago 15 replies

Hello Forum, near any radiating source like an antenna there is a region called the reactive field: the E and H field are 90 degrees out of...

Hello Forum, near any radiating source like an antenna there is a region called the reactive field: the E and H field are 90 degrees out of phase. The reactive field is region where there is no radiated power...... It acts as a storage power. During one cycle power is given and taken back... I am having a hard time understanding what that means. What does it means that energy is given and...


OFDM average power

Started by Snowball in comp.dsp19 years ago 11 replies

Hi, I understand the problem of high Peak to Average Power Ratio in OFDM. However, I am not sure how the average power of an OFDM signal...

Hi, I understand the problem of high Peak to Average Power Ratio in OFDM. However, I am not sure how the average power of an OFDM signal is calculated. Suppose you have an N-carrier transmitter where the average power per carrier is p, what would the average power of the OFDM signal be? Thanks.


What is the lowest power dsp ?

Started by Donald in comp.dsp19 years ago 8 replies

I have been looking at the many low power single chip processors available. But most are only 16 Mhz. I know that the higher the speed the more...

I have been looking at the many low power single chip processors available. But most are only 16 Mhz. I know that the higher the speed the more the current. Are there any low power DSP chips available that compare to TI MSPxxx ? Thanks


This is daft FIR power

Started by HardySpicer in comp.dsp13 years ago 22 replies

suppose a first order FIR filter H(z)=1+az^-1 has white noise of unit variance (zero mean) ) passed through it. Then the output power...

suppose a first order FIR filter H(z)=1+az^-1 has white noise of unit variance (zero mean) ) passed through it. Then the output power (variance) will be (1+a^2) X1 which is always greater than the input power?


N-pt DFT where n != power of 2

Started by dspdummy in comp.dsp15 years ago 45 replies

I know that an N-pt DFT can be replaced by an FFT to save operations if N is a power of 2. What can I do if N is NOT a power of 2 to avoid the...

I know that an N-pt DFT can be replaced by an FFT to save operations if N is a power of 2. What can I do if N is NOT a power of 2 to avoid the DFT? I need, nevertheless, the exact result. Thanks


The relationship between power density and power spectral density

Started by Anonymous in comp.dsp19 years ago 3 replies

Hi! Is there a relationhsip between power density (Watt/m^2) and power spectral density (dbm/Hz) ? Thanks Suterr

Hi! Is there a relationhsip between power density (Watt/m^2) and power spectral density (dbm/Hz) ? Thanks Suterr


Goertzel Alogorithm Stability in Low SNR

Started by superlou in comp.dsp17 years ago 13 replies

Hi everyone, I have been using a Goertzel algorithm to measure the power of 50 and 60 Hz tones in ADC data on a C6713 demo board. The...

Hi everyone, I have been using a Goertzel algorithm to measure the power of 50 and 60 Hz tones in ADC data on a C6713 demo board. The technique is very succesful given a strong signal tone. Given a signficant tone, the measured power levels match precisely the input power and have a very low varying range (about 1dB). However, as the signal decreases, the variance of the measured power incre...


power spectral density and energy under 500 hz

Started by stromhau in comp.dsp17 years ago 7 replies

Hi, If i calculate the power spectral density of a speech signal using Welchs method i get power/Hz, right ? If i want to find power or...

Hi, If i calculate the power spectral density of a speech signal using Welchs method i get power/Hz, right ? If i want to find power or energy under 500 Hz i just integrate(or square) from 0-500 Hz? If this is correct would it be the same if i low passed the signal at 500 Hz, and apply Welch? Tommy,


Hilbert transform and SSB power??

Started by Bob in comp.dsp20 years ago 1 reply

I have a question on the power of SSB (Single side band) AM. if transmitted signal is expressed as: u(t)=Ac*m(t)*cos(2pi*fc*t) plus minus...

I have a question on the power of SSB (Single side band) AM. if transmitted signal is expressed as: u(t)=Ac*m(t)*cos(2pi*fc*t) plus minus Ac*H[m(t)]*sin(2*pi*fc*t), Ac=carrier amplitude, fc=carrier frequency, m(t)=message signal, and H[m(t)] is Hilbert transform of m(t). What is the equation for received power (Pr) in terms of power of message signal (Pm)? Some books say Pr=[(Ac^2)...


Power value of signal estimated in Spectrum

Started by Anonymous in comp.dsp10 years ago 3 replies

Hi, I was thinking that the peak value observed at the power spectrum for a single tone signal will be the same as its power, but I did not see...

Hi, I was thinking that the peak value observed at the power spectrum for a single tone signal will be the same as its power, but I did not see that when I coded it in matlab when verification. In the matlab code, I was expecting to see the peak power value of -3dB but what I observed is -9dB when using matlab function 'periodogram', and -11.8dB when I later coded the periodogram


Re: Hilbert transform and SSB power??

Started by AG in comp.dsp20 years ago

Bob wrote: > I have a question on the power of SSB (Single side band) AM. > > if transmitted signal is expressed as: > > ...

Bob wrote: > I have a question on the power of SSB (Single side band) AM. > > if transmitted signal is expressed as: > > u(t)=Ac*m(t)*cos(2pi*fc*t) plus minus Ac*H[m(t)]*sin(2*pi*fc*t), > > Ac=carrier amplitude, fc=carrier frequency, m(t)=message signal, and > H[m(t)] is Hilbert transform of m(t). What is the equation for > received power (Pr) in terms of power of message signal (P


Getting the Power Spectra Distribution

Started by Anonymous in comp.dsp18 years ago

Hi all, I have a time series of 2900 elements. I want to apply the Power Spectra Distribution. I want to know if someone knows a Practical...

Hi all, I have a time series of 2900 elements. I want to apply the Power Spectra Distribution. I want to know if someone knows a Practical Guide for interpretating the results (or some pitfalls that can happens when getting the Power Spectra) Thanks, Alex


21161 power-up problem

Started by Anonymous in comp.dsp19 years ago 7 replies

Hi On some of the 21161 based boards in my application I see a problem such that the chip does not power-up properly every time. I don't...

Hi On some of the 21161 based boards in my application I see a problem such that the chip does not power-up properly every time. I don't know what exactly happens, but the DSP is not running as expected and it *can't* be brought out of that state by a hardware reset. Power cycling is the only way to cure it. Does anybody have an idea what that could be? I checked all the unused pins for...


Adjusting Matlab for 50 ohm impedance

Started by BH in comp.dsp10 years ago 1 reply

I am trying to measure power of a complex waveform with power in multiple frequency bins. Matlab gave a good example on their topic 'Measuring...

I am trying to measure power of a complex waveform with power in multiple frequency bins. Matlab gave a good example on their topic 'Measuring the Power of Deterministic Periodic Signals' http://www.mathworks.com/help/signal/examples/measuring-the-power-of-deterministic-periodic-signals.html I think in both examples they assume a resistance of 1 ohm, but my system is RF and ha


Transmit Power

Started by cau2danang in comp.dsp17 years ago 8 replies

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...

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.


WIRELESS CHANNEL ..........

Started by dania in comp.dsp15 years ago 1 reply

Hello My name is Dania, I am new in WiMAX, I am trying to simulate wireless channel for subscriber station (SS), I am using the formula...

Hello My name is Dania, I am new in WiMAX, I am trying to simulate wireless channel for subscriber station (SS), I am using the formula received signal power (RSP): Pr=Pt P0 xR(do/d)? Or in dB Pr(d)[dB] = Pt [dB]+P0 [dB] + 10 ? log(d0 /d )+X[dB] + R[dB] Where Pr(d)[dB] is the received power at SS, Pt [dB] transmitted power from BS, P0 [dB] pathloss at reference distance, ? p


questions about wireless channel???

Started by dania in comp.dsp15 years ago

Hello My name is Dania, I am new in WiMAX, I am trying to simulate wireless channel for subscriber station (SS), I am using the formula...

Hello My name is Dania, I am new in WiMAX, I am trying to simulate wireless channel for subscriber station (SS), I am using the formula received signal power (RSP): Pr=Pt P0 xR(do/d)? Or in dB Pr(d)[dB] = Pt [dB]+P0 [dB] + 10 ? log(d0 /d )+X[dB] + R[dB] Where Pr(d)[dB] is the received power at SS, Pt [dB] transmitted power from BS, P0 [dB] pathloss at reference distance, ? p