Help me make a bandpass filter with frequency between 925 and 970 MHz

[bt87]

can anybody help me in making bandpass filter which will pass frequencies between 925 to 970 Mhz , and after that pass a square wave in this filter and then check the output frequencies(using FFT) and plot the output waveform???

Thanks

 

[Aya2002]

matlab square wave code

hay did you checked on matlab file center?

 

[Communications_Engineer]

generate square wave matlab

so whats the problem... if your are good at Matlab you can use the fir1 command to design a bandpass filter. Then create a square wave signal and use the filter command to take the output. To get the frequency response you can use the fft command.

If not you are not that good, design the filter using FDAtool, export it to Simulink or Matlab and generate a square wave there and find the frequency domain response.

 

[bt87]

matlab filtering an input square wave

so whats the problem... if your are good at Matlab you can use the fir1 command to design a bandpass filter. Then create a square wave signal and use the filter command to take the output. To get the frequency response you can use the fft command.

If not you are not that good, design the filter using FDAtool, export it to Simulink or Matlab and generate a square wave there and find the frequency domain response.

but when i take fft it shows some odds lines and the real frequency response!!!

 

[Communications_Engineer]

bandpass filter odd order fdatool

yeah... I know.... from what you just wrote I imagine you are a rookie. Any way, let me explain.... The fft will give you discrete points in complex frequency (complex only due to the presence of the in-phase and the quadrature component at the same time). Now, if you want to have the frequency response (magnitude) then try this

plot(20*log10(abs(fft(y,2048))));

where y = h*x (which you get by using the filter command)

If this still doesn't work.... or you don't understand then put your code here, I'll point out the place where your are going wrong

Like ramyaravi says, "Happy Learning!"

------------------------------------------------------------
groups.yahoo.com/group/telecom_research

 

[xulfee]

generate square signal in matlab

use fdatool n give ur specification there

 

[bt87]

need help to put codes in matlab

yeah... I know.... from what you just wrote I imagine you are a rookie. Any way, let me explain.... The fft will give you discrete points in complex frequency (complex only due to the presence of the in-phase and the quadrature component at the same time). Now, if you want to have the frequency response (magnitude) then try this

plot(20*log10(abs(fft(y,2048))));

where y = h*x (which you get by using the filter command)

If this still doesn't work.... or you don't understand then put your code here, I'll point out the place where your are going wrong

Like ramyaravi says, "Happy Learning!"

------------------------------------------------------------
groups.yahoo.com/group/telecom_research

here is my code:
In Attachment.

 

[bt87]

matlab continuous wave signal generation

use fdatool n give ur specification there

how to input square wave in the filter we got from fdatool.

 

[Communications_Engineer]

export wave frequency matlab

use fdatool n give ur specification there

how to input square wave in the filter we got from fdatool.

Export your filter from FDAtool to simulink. In Simulink, use the signal generator option to create the square wave. To look at the output in time domain use the"time scope" from the Sinks of the Signal Processing Blockset and for frequency domain use the "spectrum scope", again from the Sinks of the Signal Processing Blockset

One word of advice, you would have been better off putting your code here directly rather than putting in a file to be downloaded. Most people will not download a file that is useless to them and then read and upload it back with corrections. I hope you understand.

How are you xulfee, I'm waiting for you to answer my question on DSP

 

[bt87]

matlab frequency response of square wave input

use fdatool n give ur specification there

how to input square wave in the filter we got from fdatool.

Export your filter from FDAtool to simulink. In Simulink, use the signal generator option to create the square wave. To look at the output in time domain use the"time scope" from the Sinks of the Signal Processing Blockset and for frequency domain use the "spectrum scope", again from the Sinks of the Signal Processing Blockset

One word of advice, you would have been better off putting your code here directly rather than putting in a file to be downloaded. Most people will not download a file that is useless to them and then read and upload it back with corrections. I hope you understand.

How are you xulfee, I'm waiting for you to answer my question on DSP

i have uploaded the file plz chk the 3rd last post!!!!
and simulink is giving this error:
"Error reported by S-function 'sdspdelay' in 'Untitled/Filter/BodyLDelay4':
Input to block must have a discrete sample time"

 

[Communications_Engineer]

simulink of matlab help in scope

use fdatool n give ur specification there

how to input square wave in the filter we got from fdatool.

Export your filter from FDAtool to simulink. In Simulink, use the signal generator option to create the square wave. To look at the output in time domain use the"time scope" from the Sinks of the Signal Processing Blockset and for frequency domain use the "spectrum scope", again from the Sinks of the Signal Processing Blockset

One word of advice, you would have been better off putting your code here directly rather than putting in a file to be downloaded. Most people will not download a file that is useless to them and then read and upload it back with corrections. I hope you understand.

How are you xulfee, I'm waiting for you to answer my question on DSP

i have uploaded the file plz chk the 3rd last post!!!!
and simulink is giving this error:
"Error reported by S-function 'sdspdelay' in 'Untitled/Filter/BodyLDelay4':
Input to block must have a discrete sample time"

You must be using continuous time input to your filter. Is this your homework or assignment?

 

[bt87]

matlab magnitude time index wav

use fdatool n give ur specification there

how to input square wave in the filter we got from fdatool.

Export your filter from FDAtool to simulink. In Simulink, use the signal generator option to create the square wave. To look at the output in time domain use the"time scope" from the Sinks of the Signal Processing Blockset and for frequency domain use the "spectrum scope", again from the Sinks of the Signal Processing Blockset

One word of advice, you would have been better off putting your code here directly rather than putting in a file to be downloaded. Most people will not download a file that is useless to them and then read and upload it back with corrections. I hope you understand.

How are you xulfee, I'm waiting for you to answer my question on DSP

i have uploaded the file plz chk the 3rd last post!!!!
and simulink is giving this error:
"Error reported by S-function 'sdspdelay' in 'Untitled/Filter/BodyLDelay4':
Input to block must have a discrete sample time"

You must be using continuous time input to your filter. Is this your homework or assignment?

well you can say that......
plz edit the code i provided and plz implement this on that.....

 

[Communications_Engineer]

fdatool use filter matlab

okay I'm busy right now, I'll upload it tonight

 

[bt87]

phase response filter simulink

okay I'm busy right now, I'll upload it tonight

tnx i vll w8..