Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [pll]

The tag has no usage guidance.

1
vote
0answers
30 views

How does a Costas Loop lock to one of multiple BPSK signals

I've been looking into how GPS receivers work in terms of signal processing. When a GPS receiver tracks the received signal, it often uses a Costas loop to synchronize the carrier. How that works ...
1
vote
0answers
54 views

Residual carrier tracking with PLL

Residual carrier systems such as PCM/PM/NRZ and PCM/PM/Bi-phase are common in space applications. Compared to suppressed-carrier systems such as BPSK, the literature sources on residual-carrier ...
3
votes
1answer
90 views

GNU Radio loop bandwidth normalization

From GNU Radio documentation, the control_loop block proposes loop bandwidth values in the range $[\frac{2\pi}{200}, \frac{2\pi}{100}]$ in radians per sample. Some blocks, like the new timing symbol ...
1
vote
1answer
34 views

upconverting a kHz/MHz signal to GHz

I want to know how in practice we can take a kHz/MHz signal to a GHz band? Suppose we have an FSK modulated signal at around 300 kHz (or 20 MHz). I want to take it to 3.5 GHz, so about 3499700 kHz ...
1
vote
1answer
93 views

Basic PLL theory: voltage-controlled oscillator confusion

I am trying to write my first PLL in Python, and I've been making use of this excellent tutorial: http://www.pythonpowerelectronics.com/contents/tutorials/tutorial1/pll_tutorial.pdf Reading through ...
2
votes
0answers
81 views

Dynamic loop bandwidth for a Costas loop

I'm using a Costas loop for carrier recovery. The BER vs SNR (from GNU Radio Simulation) curve for different loop bandwidths (0.03,0.05 and 0.07) is shown in the graph below. It can be seen that the ...
1
vote
2answers
114 views

Software PLL tracking of carrier frequency in bandlimited transmission

My understanding is that a PLL(either in hardware or software) can recover the carrier frequency(or be used to correct the frequency offset) of a system. My question is how does this work when the ...
2
votes
1answer
182 views

Timing recovery in GNU Radio : Variable rate vs Fixed rate operation

I have been wondering about the implementation of timing recovery blocks in gnuradio. In literature, for asynchronous sampling, all that is needed are error detector (MM, ML, Gardner etc), a loop ...
1
vote
0answers
256 views

Carrier recovery with the Costas loop : PLL pull-in range

I have created a channel model in GNU Radio (a modified version of the default GNU Radio Channel Block). Its performance under AWGN (without timing, phase or frequency offsets) aligns properly with ...
2
votes
1answer
309 views

PLL phase and frequency characteristics

I'm currently working with BPSK carrier phase and frequency recovery in GNU Radio. I have been able to use Costas loop and Frequency locked loop (four carrier acquisition) which are based on the ...
1
vote
2answers
91 views

Phase ambiguity in QAM modulation

I'm currently studying a decision directed carrier recovery scheme. Basically a PLL try to estimate the phase error in the current received symbol, the phase detector compensate the incoming symbol's ...
0
votes
1answer
135 views

Is Phase Locked Loop is essential for BPSK signal reception?

I'm noob in DSP studying BPSK communication between speaker and microphone using acoustic signal. I read article of this BPSK communication which says it needs Phase Locked Loop(PLL) sequence to match ...
3
votes
1answer
199 views

Transfer function of a PLL Loop Filter that can support a linearly increasing (chirping) frequency

What is a transfer function for a the loop filter of a PLL that can track a sinusoid of the form: \begin{equation} x(t)=\cos\left(2\pi\left(\frac{1}{2}c_0t^2 + f_0t + \phi_0\right)\right) \end{...
1
vote
0answers
154 views

Unable to stabilize 8-PSK signal with self designed costas loop

I am trying to make a signal processing block which implements the costas loop to stabilize an 8-PSK signal. Here is the flowgraph with "costas_loop" being my block. My workflow is the following - <...
1
vote
1answer
3k views

How to correct the phase offset for QPSK I-Q data

I have an I-Q data of QPSK modulation, the data is is smeared and I have to correct the phase offset that causes the smearing problem, how can I apply the Phased-locked loop or the Costas loop on this ...
4
votes
0answers
291 views

Symbol timing recovery design

I am trying to design the Symbol timing recovery(#STR) block of #DVBS Receiver. These are the specifications Symbol rate ($f_s$) = $2\textrm{ MHz}$ Acquisition range = $10\%$ of Symbol rate ...
0
votes
0answers
183 views

How to implement PLL blocks in MATLAB

I want to implement a PLL in MATLAB with individual components as Phase Detector, LPF and VCO. My problem is in implementing the LPF. I have determined the values of the pole and zero for the Laplace ...
1
vote
2answers
792 views

How to remove 50 Hz frequency noise from a PCM file?

Are you kind to tell me the odds or the means by which should I grab a clean signal with the $~50 \mathrm{Hz}$ hum removed using just programming? I managed to make a program in Visual-C that ...
3
votes
0answers
221 views

Amplitude/phase recovery on noisy signal

I have a noisy signal that has an ac component of fixed frequency but variable amplitude and phase. I'd like to recover the ac component. The signal (blue trace) is mostly smooth, but has a few ...
0
votes
0answers
94 views

phase locked loop

I have seen that to get the phase angle of a signal, we have to use PLLs. this PLL is modeling in order to get the phase angle about one frequency, which is the free running frequency of the VCO. If ...
0
votes
2answers
222 views

FM demodulation amplifier with saturation

I'm trying to understand how FM demodulation works. I read a lot on the internet and as far as I understand, the main process is to extract the phase difference (that is also the output) between a ...
1
vote
3answers
920 views

PLL and zero crossing detection

Is there an algorithm which can give the frequency and phase of a three phase signal (three phase voltages) without using zero crossing detection. I mean an algorithm which is done in open loop.
1
vote
1answer
178 views

Software implemented PLLs for signal synchronization, why use them?

In short I'm recreating a program that reads 3 sinusoidal signals through an ADC performs some manipulations and then reproduces these signals through a DAC. In order to reproduce these signals I need ...
2
votes
1answer
211 views

Why do most digital pll's only use the positive zero crossing?

I've been trying to get my head around digital plls from knowing nothing and seen that most examples only use the positive zero crossing, not the negative. I've tried to find the answer but the best i ...
2
votes
2answers
1k views

High modulation index PSK - carrier recovery

How to recover the carrier of a PSK signal that has high modulation index (eg. 750 symbols per second at carrier frequency 1500 Hz)? I guess that a PLL will not be able to lock onto it with such ...
2
votes
0answers
421 views

Doppler shift using PLL

I am trying to apply phase lock loop to calculate phase shift due to doppler effect and finally calculate the doppler frequency($\Delta f$). I am assuming that the received wave is of the form, $r(t) =...
1
vote
2answers
251 views

Melodic or tonal pitch contour tracking?

What algorithms or methods can be used for the tracking of audio pitch contours? (Such as in musical vibrato and glissando, or for tonal vowels in languages such as Chinese?). Will a PLL work even ...
5
votes
1answer
651 views

Phase Locked Loop Basics

I am trying to better understand discrete-time PLLs. I drew a picture of a simple feedback system here: I want to be able to describe and understand the system at v(t) and y(t). I found a fairly good ...