software-defined-radio | 易学教程

UHD USRP device lacks capacity

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问题 I'm using Redhawk 1.10.0 on a CentOS 6.5 machine 64 bit and USRP b100 with UHD driver 3.7.2. The USRP b100 is recognized correctly by the system. It is a USB device. I downloaded the latest version of UHD_USRP Device ver. 3.0 for REDHAWK and I created a Node including a GPP and a UHD_USRP devices. The Node is started without any problem but when I run a simple waveform to read data from the USRP as a RX_DIGITIZER I got the following error: Failed to create application: usrp_test_248_173059195

How exactly is hier_block 's behaviour different then that of a sync_block in GNU Radio?

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问题 This is a continuation of this question. I understand that we cannot access input_items in __init__ of a sync_block but we can do so in hier_block (eg. here). I wanted to add a panel on the top block frame which can only be done by assigning a panel to self.win in __init__ (like in the hier_block example). If I try to assign a panel to self.win inside the work function of a sync_block then it gives the error : 'xyz' object has no attribute 'win' . Though it works if I assign a panel to self

QPSK transmission and reception in GNURadio

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问题 I have implemented this: Constellation plot of receiver side is same as that of transmitter but it disappears for some moment and is not continuous, It flickers and keeps on moving around and for a very short moment show a garbage plot also. How to resolve that to get a correct continuous plot? 回答1: Never use a "Throttle" block in a hardware flow graph. What it does is just slow down the processing speed "about roughly" to the requested rate on average. That will sooner or later lead to your

Software defined radio AM band sample source

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问题 I'm interested in Software Defined Radio. I have basically no experience in any of the electrical engineering or math topics involved, but I'm reading... Rather than trying to deal with the hardware aspect of the antenna and the ADC, I imagine it'd be fun enough (and cheaper) to play with some pre-recorded (or even live!) sample streams of the AM band. From what I've learned so far, it seems to me that the AM format would be the easiest to decipher - a narrow bandpass/windowing function over

Generate 16 QAM signal

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问题 I know the way to generate QPSK signals using the following TxS=round(rand(1,N))*2-1; % QPSK symbols are transmitted symbols TxS=TxS+sqrt(-1)*(round(rand(1,N))*2-1); In the above, the symbols are 2 alphabets +1/-1. But I cannot understand how to generate 16- Quadrature Amplitude Modulation signal for the same alphabet space? Is it possible? Or what is the usual way for generating ? Also, is it a practice to work with complex signals and not real ? 回答1: Take a look at this: http://www

voltage pulse from USRP when using simple GNU Radio flowgraph from Python

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问题 This is a follow-up to my earlier question: FFT in non-flowgraph centered application different from flowgraph centered apps like uhd_fft In an attempt to better clarify the issue, I've boiled my code down to about ~30 LOC and have removed as much processing out of the flowgraph as possible. The issue that I'm having is that, although the USRP is tuned to a frequency only once, each run of the flowgraph has about 70 ms of junk data. I'm fully aware that a certain amount of "junk" samples are

GFSK demodulation with Xlating filter in GNU Radio

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问题 I have been trying to demodulate a GFSK signal for months now using GNU Radio with USRP B210. Unfortunately, I haven't found even a single decent book on GNU Radio and hence most of my references are based on some random websites including the official GNU Radio page. The GFSK signal comes from a cubesat in the lab. At the moment, it is transmitting a '10101010 ...... ' test signal. The GFSK modulation index used is 0.6667 and the data rate is 9600 bps. My flowgraph, as shown in the diagram

Generate 16 QAM signal

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I know the way to generate QPSK signals using the following TxS=round(rand(1,N))*2-1; % QPSK symbols are transmitted symbols TxS=TxS+sqrt(-1)*(round(rand(1,N))*2-1); In the above, the symbols are 2 alphabets +1/-1. But I cannot understand how to generate 16- Quadrature Amplitude Modulation signal for the same alphabet space? Is it possible? Or what is the usual way for generating ? Also, is it a practice to work with complex signals and not real ? Take a look at this: http://www.mathworks.com/help/comm/ref/comm.rectangularqamdemodulator-class.html hMod = comm.RectangularQAMModulator(

Software defined radio AM band sample source

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I'm interested in Software Defined Radio. I have basically no experience in any of the electrical engineering or math topics involved, but I'm reading... Rather than trying to deal with the hardware aspect of the antenna and the ADC, I imagine it'd be fun enough (and cheaper) to play with some pre-recorded (or even live!) sample streams of the AM band. From what I've learned so far, it seems to me that the AM format would be the easiest to decipher - a narrow bandpass/windowing function over the entire spectrum to get any target frequency, then a short running average transform(?) to get

How exactly is hier_block 's behaviour different then that of a sync_block in GNU Radio?

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This is a continuation of this question. I understand that we cannot access input_items in __init__ of a sync_block but we can do so in hier_block (eg. here ). I wanted to add a panel on the top block frame which can only be done by assigning a panel to self.win in __init__ (like in the hier_block example). If I try to assign a panel to self.win inside the work function of a sync_block then it gives the error : 'xyz' object has no attribute 'win' . Though it works if I assign a panel to self.win inside __init__ of a sync_block ( that's why I wanted to access input_items inside __init__ in the