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368 Threads found on Carrier Phase
Frequency Modulation (FM): The carrier frequency 'fc' is linearly deviated by the message (modulating) signal 'm(t)', and the linear constant 'fm' is known as the Frequency Modulation Index. fs(t) = fc + fm*m(t) thus S(t) = A*cos phase Modulation (PM): The carrier phase is linearly deviated by the messag
Saturated is good. Linear region region is best. Operation in a partially saturated mode (like around the 1 dB compression point) is the worst for phase noise, because of the am to pm conversion. Fully saturated, there could be more 1/f noise, so depending on your close to the carrier phase noise spec, you could have some trouble, but (...)
Matlab phase and carrier estimation is needed(with ml criterion)
Please help me about Matlab code (M.file) for "phase noise" (How to simulate the phase noise). 1. The phase noise due to laser diode 2. The phase noise due to Local oscillator Your help is highly appreciated. this is for OSCILLATOR:
Hi, Can anyone help me in understanding this topic? I know how the code range mesurement is performed but what about the carrier phase measurements? Thanx
I am not a DSP guy by any means. But I have a problem that might be best solved by a DSP chip. If I have an IF signal, say at 10 MHz unmodulated carrier, and I want to compute its phase to a resolution of 0.1 degree, how would I have to process it. In other words, what ADC clock rate, how many bits in the ADC, and how many samples of the 10 MHz
See my simple simulink models: Key words: PSK, QPSK, QAM, square root raised cosine filter, differential coding, feedback feedforward NDA decision-directed symbol timing carrier phase recovery synchronization, Gardner Muller and Mueller timing detector, Farrow interpolator, automatic g
Hello, phase noise is often expressed as the noise density, PSD , referenced to the carrier power at a certain frequency offset from the carrier. phase noise, Side band noise = (PSD (at offset) ) / (carrier power) When you convert this to decibels, you get dBc/Hz. The "c" denotes that the (...)
For very basics you can check carrier phase tracking title in More detailed info with codes
Hi, Can carrier recovery be achieved through a digitized (i.e. a single bit stream signal from a comparator, not ADC) I and Q signal?
The PLL has a loop bandwidth. If you are inside of +/- the loop bandwidth from the VCO carrier, then the phase noise of the output is no better than 20 Log N + Reference phase noise. i.e. the reference phase noise as degraded by the PLL. If you are outside of the loop bandwidth, the phase noise can be (...)
I guess Fant has probably presentetd the best way of acheiving lowest phase noise! You said that you had HP10811 on hand and this is a sc-cut ovencontrolled oscillator which used to be THE standard which everyone else did compare to. I am not sure what the phase noise is at 10 Hz offset but I would guess -130 to -135 dBc/Hz. Ulrich Rohde shows
to point to the drip rf is a circle like a plop but ssb is a plop plipp { the plipp being the next circle out like mushrooms grow but at the frq in circles at your antenna {dipole} radiation pattern is ssb the plipp of the plop without the plop{the plop is filtered out s
The modulation is 16 or 64 QAM. It is claimed that this can be done on existing short wave transmitters. I suspect that the carrier phase is set at the oscillator and the amplitude is set by the usual AM modulation. This way a vector is made to the constalation point. I ffurther suspect that the output signal is sampled and demodulated as part o
phase modulation is easily done by using a varicap diode at the referance xtal in the pll this way you freq modulate the referance oscillator of the pll a little this results in phase modulation of the carrier another way is too do a similar thing too the vco but this gives phase freq (...)
group delay of filter, Sideband Suppression and carrier Suppression
Hello, I have some problems about using PSS & Pnoise analysis in SpectreRF, which can simulate the phase Noise of PLL. And my design of the PLL is used for clock generator in MCU. So the reference frequency is 1MHz and the VCO is about 30MHz. My problems are: 1, Is the periodic ac source added to the reference signal? 2, If it is, how can I obt
it means that @10 KHz offset we measure the phase noise at carrier frequency plus (+) or minuse (-) 10khz? is it truse?
above 3 is the max value,its average value is around 1.2,is it high?if it is,is there any way to lower it? 3% RMS is ok for GSM/EDGE. 3degrees max is not terrible, but could probably be improved. Maybe is it a GSM signal ?. If you are using an IQ modulator check : i) Check phase and amplitude balance of the mo
phase noise is the ratio in dB between the noise level at X KHz from carrier to the total signal power. A simple way to measure is by a spectrum analyzer. The signallooks like a skirt. Then the difference in dB between the peak to the skirt noise level at let say 100KHz is the phase moise. The term phase noise come becouse (...)
It is your quote :-) one modulator is driven by the subcarrier at sine phase ,the other modulator is driven by the subcarrier at cosine phase You hqve two modulators one is fed directly by carrier, other with carrier sihted at 90 degrees( pi/2 radians) Look here
Some answers: 1. It's not so simple: the VCO is just one element of a PLL. When closing the loop (is it clear why we use PLL instead fo bare VCOs?) in a PLL the noise is shaped by the transfer function of the PLL. As the VCO transfer function is high pass type, there is a certain offset from the carrier at which the VCO noise is cutted out. 2.
x(t) = Real{*exp(j*w0*t)} Any passband signal with carrier w0 can be expressed in this form, as the product of a complex baseband signal (I+j*Q) by the complex carrier exp(j*w0*t). The result is modulated both in amplitude and phase These (I and Q) are the in-phase and quadrature components. The representation of in
Good initial coverage of MPSK carrier extraction is given within "Digital Communications" by Proakis. There is given a description of generalized Costas loop, too. If you want just to experiment, you can also try to use a QPSK Costas loop, but first you should square the input signal to reduce nuber of phase stages on 4 and at the end divide the fr
You can use a Squaring loop or Costas loop (it is same actualy) to recover your carrier phase. The RF mixer does not have to be coherent. You can still do coherent dectection at IF using Squaring loop to generate coherent LO. BUt RF mixer LO frequency need to be very stable. Most of the system, only TCXO for referent frequency is ok. You can also d
If your VCO is frequency modulated, how you will be able to measure PN ?? It's impossible !! PN is essentially frequency/phase modulation with noise and how you will extract this deviation from main modulation?? I mean, when you make a frequency/phase modulation, how will you define this noise modulated signal?? The way of measurement of PN is
biff44 you cannot use spectrum analyzer for phase noise measurement of 160 dBc, it's limited by its dynamic range not more than 155 dB in high end Agilent or R&S. There is a possibility to do that with spectrum + notch + LNA setup (filter the carrier and amplify the noise with LNA), but it's a complex setup. Latest VCO/PLL meter has this capab
Oscillator drift is measured in PPM. In your case 30 kHz -------- = 7.5e-6 = 7.5 PPM 4 GHz This isn't too bad. I think there is a signal track option in the Spectrum analyzer to make sure it track's the carrier frequency, try turning that on. Dave
Group velocity is applicable when there is information or modulation added to a carrier frequency. As an example, if you send a pulsed carrier thru a network, the group velocity can be derived from the time delay (or difference) between the input rise time to the output rise time and the distance traveled.
Yes, if the phase-noise of the analyzer is much better than the osc you trying to measure. To get phase noise reading. Read of dBc of your carrier at the required offset and add (10Ślog ) -RBW is the Resolution Bandwidth setting of your analyzer, 1kHz, 3kHz etc.
I am running simulations with a LC oscillator and trying to see the output phase noise due to a given noise source. Here is how I have been doing: 1. run the transient simulation for a while 2. compute the spetrum of the output signal using FFT, and plot it in dB 3. read the power density (dB) at a given offset frequency from the first
I'm sorry for my missleading. I needn't design a vco and get its phase noise. What I want is to represent a vco with an user specified phase noise in Cadence or ADS. I would like to know the relation between phase noise and SNR of which the carrier is demodulated by a FM demodulator.
carrier power is either in watts of dBm. phase noise is in dBc/Hz. How is it possible to say "phase noise at 10Hz offset freqeuncy is higher 13dB than carrier power"
Hi all, My application is a satellite receiver with only one channel (not multi-channel application). Bit rate of digital message is 400bps. The specification says: "The data are encoded biphase-L or Manchester. The carrier is phase-modulated positive and negative 0.8 +/-0.025 radians peak, referenced to an unmodulated (...)
sorry fot that is at 600kHz offset from the carrier
There are a number of ways to do it. A simple way is to use a filter/amplifier combination. Assume you have a 1 GHz clock. Basically, I would build a narrow band notch filter to notch out the power by say 20 dB at 1 GHz, but to be done notching out at +/- 100 KHz from 1 GHz. Then I would pass the notched signal thru a 20 dB gain amplifier and
Hi all, I am reading the book "OFDM Wireless LANs, A Theoretical and Practical Guide" (can be download from EDAboard) and using the Matlab code with the book. I am confused with two parameter: (1) Frequency Error; (2) phase Noise; Is (1) related to carrier frequency? What's (2) means? Any suggestions will be appreciated! Davy
Dear all, Recently, I read the paper by Ken"Predicting the phase noise and jitter of PLL-Based frequency It is really a wonderful work for pll disigners. Afer reading the paper, however, I am confused by some questions. I hope experienced experts who read the paper can give me some hints.
Yeah, I have a bunch of those. Pretty essential if you are doing some sort of manual phase noise or carrier nulling tests. You see them on ebay every once in a while.
Hi, i couldn't find any topic related to phase noise measurement. I suppose to do some phase noise measurement. There are different ways to measure phase noise, but depents how low noise is the signal u want to measure. An easy one is using a spectrum analyser though needs the internall referense oscillator of the spectrum a
The basics are: Set the frequency bandwidth to see the area you want to. If you are looking at close in phase noise, sweep +/- 100 KHz for instnace. Leave the video bandwidth on auto, unless you see a lot of jagged data that you think might not be real, then lower the bandwidth a little. Narrow video bandwidth throws away a lot of informati
1/f , 1/f? and 1/f? is transpoded flicker noise to your carrier. Your semiconductor device exhibits low frequency excess noise in the form of 1/f, that modulates your carrier signal and creates AM and PM components that translate as close to carrier sidebands in your spectrum. The actuall mechanisms of how 1/f noise is transpoded to (...)
Anyone have any good ideas on how to detect the presence and magnitude of multipath error on a fixed carrier frequency. In other words, if I transmit from point A to point B, and I measure the phase shift (or time delay), if there is an echo coming via a multipath source that is adding a phase shift error, how might I detect how much (...)
hi, in dqpsk modulation, we transmit two bits of digital data on a phase which is pi/4 or odd multiple of it like 3*pi/4, 5*pi/4.......... Since in this modulationwe transmit two bits on a single carrier, this technique is relatively more efficient in data transmission.
I am testing a VCO using spectrum analyzer. I found the frequency is changing with time esp. when the frequency span is small (5MHz). So it is very hard to get a good phase noise measurement since the carrier power is not stable. Is there any way to overcome this problem? Thanks.
It a noise in a 1Hz bandwidth. In PLL circuits it is deifined at a spot frequency like phase noise at 10KHz is -90dBc /Hz. Here 10KHz is the spot freq where the phase noise is measured and 90dBc is the relative level of the noise for 1Hz Bw w.r.t carrier.
If by "In band" you mean carrier sideband noise that is closer to the RF carrier than the open loop bandwidth of the PLL control loop, then it is mostly due to the crystal. The PLL will try as hard as possible to match the RF oscillator's phase, after dividing it down, to the crystal oscillator's phase. So if the crystal (...)
The simple answer is that the phase noise is additive. That is your phase noise is the, phase noise of your synthesizer added to the residual phase noise of your buffer amp. The phase noise of your buffer amp probably will degrade a little if driven hard, expecially if it is a FET amplifier. The (...)
For a VCO I measured in lab -30dBrad?/Hz of phase noise. Most of the examples I've seen express the phase noise in units of dBc/Hz, which I understand is the ratio of noise with respect of the carrier at a frequency offset. What does rad?/Hz mean ?? regards !
let me explain further. we have a TDMA kind of BPSK modulation for examle. and there is a preamble at the beginng of each fram which we must detect and justify our sampling parameters form that. the parameters are(symbol rate,ohase error, carrier exact freq, carrier phase shift) and we do not have enough time to implement timing (...)