Questions tagged [preamble]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0
votes
2answers
44 views

Preamble length and channel estimation

For OFDM we select the known gold sequence as the preamble or pilots. We can correctly estimate the channel(10 to 20taps). Is there any relationship between the length of preamble and the number of ...
0
votes
0answers
203 views

Preamble detection using cross-correlation

I am generating a preamble with a sequence of [1 -1 1 -1 1 -1....] and spread with a barker-11 sequence. Now, the transmitted signal becomes [B(Barker), -B(Inverse of Barker), B, -B,....]. In channel, ...
2
votes
2answers
1k views

Preamble Detection and Frequency Offset Estimation in radio packets

I have generated a radio packet of data with a preamble header of 0x55555555 and crc32 for the data only. The entire packet was separated in even and odd streams for I and Q. The I and Q were ...
0
votes
1answer
334 views

Why are the mark and space tones of these FSK signals reversed?

I'm working on a project involving FSK-modulated signals. I'm trying to reverse-engineer these signals to determine the preamble pattern used, because the protocol is proprietary. Shown below is a ...
3
votes
0answers
968 views

gnuradio: How can I change the value of the tag exiting the “Correlate Access Code - Tag” block?

Background: I have built a conventional demodulator in gnuradio and am trying to send payload data out of the flowgraph to an external Python script. I'm using gnuradio v3.7.12. It seems to me that ...
1
vote
0answers
143 views

OFDM Preamble Ripple Structure in Frequency Domain [closed]

After performing a time and frequency tuning of a signal, and plotting the result in frequency domain(abs value), the following ripple structure can be witnessed. The extracted bits are LFSR sequence(...
0
votes
1answer
80 views

Spectrum Sensing HW

I am interested to use an existing hardware to perform a spectrum sensing/monitoring in the frequency range of 2.2–2.6 GHz. Taking into account that the 802.11ac channels are in the range of 2.4–2.5 ...
0
votes
1answer
2k views

Find Preamble (pattern) in signal, using Corelation

I have a signal which always has the same preamble (4x 0xAA - 10101010...). I also have a signal with additive noise, and I want to find my preamble in that a noisy signal using corelation. U used ...