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Questions tagged [fsk]

Frequency Shift Keying - A digital transmission technique in which a "1" is represented by one frequency and a "0" by another. It is the digital equivalent of FM.

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How do the sx1276 radio AFC, AGC, RSSI, FEI work in FSK mode (RX)?

The sx1276 radio (https://www.semtech.fr/products/wireless-rf/lora-connect/sx1276) is commonly used in LoRA mode but it also has an FSK mode, this Q is about the FSK mode used in packet mode. This ...
TvE's user avatar
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Modulate a digital message using FSK/PSK combination

I am beginner and I want to modulate the digital signal: 101101 based on the combination: frequency/phase (2 frequencies/2 phases). For that, I set the 4 possible combinations: ...
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SX1276_FSK Modem_Maximum Payload Length

I've been scanning the SX1276 datasheet recently and found the thing that puzzled me. It says that in Packet Mode the device is using FIFO as the payload source. The maximum size is 2047 bytes for FSK/...
Bushpulbek's user avatar
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What to use as "frequency error" when determining appropriate bandwidth for 2FSK?

The datasheet for Semtech LLCC68 states, that when choosing appropriate bandwidth for 2FSK, one must obey the following constraint: $$ Bandwidth[DSB] \geqslant bitrate + 2\cdot frequency\ deviation + ...
shylent's user avatar
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SX126x IC: which is the correct frequency deviation formula?

SX126X IC datasheet page 88, I see two different formulas for the frequency deviation: Closest clue I can find is here: ...
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FSK modulation and inverting mark and space bits

Quick theory to application question. In Frequency shift keying we usually have the output of a sequence generator into a VCO, then this leads to a high frequency for the mark bit and a lower ...
Schliemann's user avatar
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FMCW or FSK radar signal processing using an Arduino Nano

I have been trying to build a car detection system with range measurement using an Arduino Nano, an AgilSense AP88 (this provides I/Q output, butI am using only the I output,) and an MPU4725 DAC (...
Magum23's user avatar
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Align symbol period in GFSK communications

To learn more about communication systems I have been using an SDR (RTL2832U) and a 918 MHz transceiver (RFD900+) which sends signals using 2 GFSK. The deviation of my RFD900+ from the center ...
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FSK Modulation in Python

I am currently writing a script that uses I/Q data to do FSK modulation. My question is about the FFT plot. I expected to have a peak at 1Hz and 2Hz which are the frequencies that represent binary 0 ...
PrematureCorn's user avatar
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949 views

FSK Modulation using I/Q

Is it possible to do FSK with I/Q data? If I/Q only shows amplitude and phase changes is there anyway I can use it to generate a frequency f1 to represent binary 1 and f2 to represent binary 0?
PrematureCorn's user avatar
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How to decode TPMS FSK signal on Universal Radio Hacker

I am capturing the TPMS sensor transmission in URH, but i am having extremely hard time to decode correctly the signal. I know exactly what is the data string that my real sensor is transmitting and i ...
Pedro Silva's user avatar
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Relation between AWGN and bit rate

I want to get the value of the maximum rate of digital information to be transmitted by carrier modulation through an AWGN channel with a bandwidth of \$ 100\ \mathrm{kHz} \$ and \$ N_o = 10^{-10}\ \...
user8836128's user avatar
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Bit error probability for BFSK

This is an assignment question. What is the probability of bit error of a BFSK modulation scheme with transmitted energy per bit Eb , in a additive white Gaussian noise channel having one-sided power ...
MAJID AHMAD's user avatar
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How can find the bandwidth of the transmitted M-FSK signal?

I'm tried to find the solution, but I failed. my question in the figure below, and the correct answer it's shown at the end of Figure. I'm using this formula but the answer is not correct! Is there ...
Abdallah_98's user avatar
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N Fractional PLL spectrum

I'm studying the different types of N-fractional PLLs based on switching between two or more frequencies to get the desired frequency. However, I'm facing difficulties to understand how the output ...
Fernando's user avatar
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PLC carrier frequency

I am trying to build a communication system over a power line using FSK. I want to stay within the frequency band A of the CENELEC protocol which goes from 3 to 95 kHz. I am trying to determine ...
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distortion on transition of bits in FSK

I have a question regarding the distortion I see at the transition of bit '0' and '1' in an FSK, I have the receiver connected to a sensing circuit at two frequencies, because my input is current ...
user3602697's user avatar
1 vote
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Coherent and non-coherent detection

Let's say I am simulating something as simple as BFSK. It has two symbols, one entirely on the real plane, and one entirely on the complex plane for representing let's say zero. That is how the ...
good_omen92's user avatar
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Transimpedance Amplifier and Photodiode for BFSK

I am working on my first transimpedence amplifier circuit and am having some trouble. I have am looking to reconstruct a BFSK signal modulated on an LED. The BFSK signal uses a 50kHz sine wave at 80mA ...
Jacob Abramow's user avatar
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1 answer
356 views

Hacking ATM with its aux port [closed]

(I opened a topic about it a few minutes ago but I thought it would be better if I ask my question more properly.) I wonder if is it possible to hacking an ATM (through it's aux port) with connecting ...
fissile_uranium's user avatar
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radio Link works with laptop but not with PC

I have a complicated issue. I set my HM-TRP radio modules to use: 117Khz receive bandwidth, 39Khz deviation frequency and 38Kbps air and data rate. The attached picture is my basic room setup for ...
Mike -- No longer here's user avatar
1 vote
1 answer
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How high should I make an FSK modulation index value?

After consulting with the radio manufacturer about a setup for my FSK radio module (HM-TRP), they have suggested I program it with the following values when setting up the module for 115kbps: ...
Mike -- No longer here's user avatar
2 votes
1 answer
134 views

ramp-up "guard" time (data receiver)

I have looked at multiple datasheets of multiple radio modules including one I'm using (HM-TRP) and none of them specify a ramp-up or a ramp-down time. According to research, this is known as the ...
Mike -- No longer here's user avatar
1 vote
1 answer
633 views

Trouble with FSK VCO modulation circuit

Circuit shown is a VCO that reliably creates a 200MHz sine wave at 3V pk-pk. I would like to use this VCO to create an FSK modulated signal. My bit 1 frequency = 200Mhz and my bit 0 frequency = 205Mhz ...
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Distinguishing simple FSK and Manchester coding?

I'm examining the signal sent by my car's fob. Using an RTL-STR and GNU Radio Companion, I've been able to capture and demodulate the signal. Now I'm working on decoding the signal. What I'm not ...
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understanding AFSK and FSK

I’d like to understand 1200Hz/2200Hz AFSK in commonly used APRS/Packet/AX.25 applications. When I look at the datasheets for some of the chips existing projects use (e.g the Si446x transceiver-on-a-...
captcha's user avatar
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Help decoding line code

I have collected a burst signal from a radio device using an RTL-SDR and gnuradio and demodulated the FSK, but am having trouble deciphering what the line code is. Signal is at 151.3MHz Here is the ...
ElDog's user avatar
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2 answers
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In CPFSK, suppose we transmit a continuous bit stream of 1, then for how long will the frequency go on increasing?

I read something about phase memory but didn't get proper information. My specific doubt is, let's say phase memory is L, then after L '1s', will we have a phase discontinuity and will the frequency ...
Aniruddha Paturkar's user avatar
8 votes
4 answers
2k views

Why do we need orthogonality for FSK carriers?

I keep on coming across a requirement for FSK carrier separation, \$1/T\$ for non-coherent detection and \$1/2T\$ for coherent detection, where \$T\$ is bit period. I understand where this comes from ...
snEE's user avatar
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Multi-fixed-station AM receiver

I'm in the pencil-and-paper stage of building a radio receiver that has the following characteristics: AM shortwave/HF three fixed frequencies - 3.33, 7.85 and 14.67 MHz single upper sideband with ...
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Build an FSK modulator using the HB100's transmitting signal

I want to use the HB100 to make an FSK modulation on a microwave signal. The reason why I use HB100 is that in this way the RF circuit is ready. I thought about doing an FSK modulator like the scheme ...
Fabio's user avatar
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Coherent FSK Modulation correlation coefficient derivation

FSK has a large bandwidth requirement and its minimum bandwidth is around \$4 B_T\$, where \$ B_T \$ is the bit rate. In a coherent FSK system the signals \$s_1(t)\$ and \$s_2(t)\$ representing bit ...
Lewis's user avatar
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1 answer
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Why radio exhibits better sensitivity with a wider deviation when Rx bandwidth remains constant

I used an RF generator transmitting FSK packets with a datarate of 50 kbps. The deviation was 12.5 kHz. With this combination of datarate and deviation the modulation index is 0.5. I found that my ...
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Generating two signals with small difference in frequency using one oscillator

I am building a data transmitter for which I chose FSK modulation. The frequencies should be around 27 MHz. I have single crystal with 27 MHz frequency and I need to get two separate frequencies that ...
Anthropomorphous Dodecahedron's user avatar
4 votes
3 answers
5k views

FSK demodulation using DSP

Especifically talking, I need to demodulate a low frequency FSK signal( betwen 120 and 140 kHz ). I already have a circuit of antenna that receive the signal and I already can sample it, but I still ...
Daniel's user avatar
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1 answer
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Stability of crystal and crystal-less oscillator transmitters

I have stumbled upon this very cheap so called "crystal-less" RF transmitter: http://www.mouser.com/ds/2/368/Si4012-35123.pdf It says there on page 5 the Carrier Frequency Accuracy is 250 ppm while ...
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FSK constellation and eye diagrams [closed]

why do constellation diagram and eye diagram not show any useful output for FSK? I have tried to find that on Simulink Mathwork, but the progress was negetive.
Ah Ali's user avatar
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How to build a FSK modulator and demodulator?

I want to build a FSK modulator and demodulator, the center frequency is 4.234MHz +-175kHz, FL is 3.951MHz, FH is 4.516MHz, mean data rate will be 564.48kbit/s. After searching the web, I found that ...
iouzzr's user avatar
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2 votes
1 answer
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Problem in FSK demodulation

I have a FSK modulated signal of binary data. This I am trying to recover using PLL. The mark and space frequencies are in the range of 1.5MHz to 7MHz. I am struggling because, the PLL output is not ...
cppiscute's user avatar
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0 answers
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FSK Bandpass Filters for 900 MHz

I'm attempting to design a basic FSK transceiver (architecture shown below) using only discrete components (transistors, diodes, resistors, etc). My idea was to separate the two binary frequency ...
Biff's user avatar
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Filtering and Delay Compensation in Matlab and Simulink

I have built a FSK modulator and demodulator in Simulink. Everything is working fine except the received signal after the channel has short spikes, which are introducing a short pulses in the ...
cppiscute's user avatar
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How to perform FSK modulation in VHDL

FSK Modulation in VHDL Hello, I have a VHDL block that performs FSK modulation. It looks like this The operation of the VHDL block goes like this. Fsk_data selects ...
Vijay Karthik's user avatar
1 vote
2 answers
810 views

Understanding this circuit for getting sensor data from an arduino to a phone via the headphone jack

I am trying to understand the circuit below which relates to getting sensor data from an arduino to a phone via the headphone jack. The instructions on this page aren't clear on what the function of ...
mpters's user avatar
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Transmitting data over inductive charging coils (or boosting RFID/NFC power supply)

I know that data can be sent over power lines through various different types of modulation - that is as far as my knowledge ends. I have a small D.I.Y. project (a board game) that requires some form ...
Escribblings's user avatar
1 vote
4 answers
901 views

Has fsk over wired communication channels ever been done?

I have done multiple searches to figure out if fsk encoding of binary data has ever been used in a "wired" communication scheme but have come up with very little. It seems, at least to me, that ...
pickledpickles's user avatar
6 votes
3 answers
2k views

Software based Caller ID project- Problem with getting caller ID signal

Nowadays, I am trying to make a Caller ID project without using Caller ID ICs. Firstly, I have done a lot of research in Google to get information of phone lines and their electrical properties. I ...
Ebubekir Çağrı Şen's user avatar
4 votes
6 answers
1k views

Identifying 40Hz frequency shift

I have a signal that is at 4 kHz. This signal shifts by 40 Hz depending on some user input. I like to detect this change in software as fast as I can. What should be the ADC frequency I should use? ...
TGG's user avatar
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Protocol design in a steel conductor

I was wondering what energy efficient protocol should I use for a FSK modulation in a steel conductor. My limitation is on the number of continuous bits I can transmit due to the charging and ...
Paul's user avatar
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How to determine a Signal Generator's Marker (Event) output delay?

I am using an Agilent N5182B Signal Generator for modulating a 2-FSK waveform on a 160MHz RF carrier. For that, I am using a baseband waveform (I/Q mode), generated by a Matlab FSK modulator script. ...
ysap's user avatar
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3 votes
1 answer
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Receiver understanding FSK bandwidth

I have a small doubt in a one way wireless communication. If I am using a receiver chip to demodulate an FSK signal. How does the receiver understands, which frequency to listen to? For example, I ...
Floyd's user avatar
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