How to synchronize the RF source having delay over time?

In summary, synchronizing an RF source with time delays involves several key steps: first, accurately measuring the delay using time-domain reflectometry or similar techniques. Next, implementing a feedback loop that adjusts the RF source based on the measured delay, which may include using phase-locked loops (PLLs) or digital signal processing. Regularly calibrating the system and compensating for environmental factors that might affect timing are also crucial. Lastly, continuous monitoring and adjustments ensure long-term synchronization effectiveness.
  • #1
K-Manu
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TL;DR Summary
RF source synchronization method
I want to synchronize the RF power supply (having jitter or delay over temp/time) to RF reference frequency with a digital delay generator, and I thought of two ways.

1) phase locked loop: it is commonly used for synchronizing the high-frequency signal, but as I know it is proper for a periodic AC source, and mine is an aperiodic source.

2) Edge-controlled phase detector: Detected phase difference between two sources and applying it to a delay generator would be the idealized method. But I could not find proper user-friendly products (IC is not proper because I'm poor at that).

or there would be a better way to solve it. Please share your experience and correct my knowledge. :)
 
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  • #2
I need some context.
What is "the RF power supply" ?
What is the HF RF source ?
What are you trying to synchronize what with ?
Why are you wanting to do that ?
 
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  • #3
Baluncore said:
I need some context.
What is "the RF power supply" ?
What is the HF RF source ?
What are you trying to synchronize what with ?
Why are you wanting to do that ?

I'm using the RF(13.56 MHz) power generator (power supply) having delay, and I wanna synchronize RF signal what I made using digital delay generator with power generator to make a pulse signal as used to external trigger.
 
  • #4
Is this RF being used for 13.56 MHz ISM (industrial, scientific or medical) dielectric heating?
What is your application?

Newer ISM equipment employs a signal generator, followed by a linear power amplifier.
Older ISM equipment employs a free running, class C oscillator, are you trying to lock that to a precise frequency?
What is the power, make and model of the 13.56 MHz RF power generator?

The answer will become obvious, once we identify the meaning of the question.
 
  • #5
Baluncore said:
Is this RF being used for 13.56 MHz ISM (industrial, scientific or medical) dielectric heating?
What is your application?

Newer ISM equipment employs a signal generator, followed by a linear power amplifier.
Older ISM equipment employs a free running, class C oscillator, are you trying to lock that to a precise frequency?
What is the power, make and model of the 13.56 MHz RF power generator?

The answer will become obvious, once we identify the meaning of the question.
Sorry to what I didn't mention about detaill information, (because I thought it was not essential.)

An RF power generator is used for gas discharge, and I wanna measure its characteristic it (via electrical probe) at the specific moment (<10 ns) in an RF period. Thus I wanna insert the external trigger signal into my electrical probe using a delay generator.

RF input Power: 170, voltage: 300-1000 V, current 0.1-0.5 mA (roughly)
 
  • #6
K-Manu said:
mine is an aperiodic source.
This is where I get confused. Say V = V0 + f(t). As you say, if f(t) is a sine wave, a PLL is a common solution,. But you say f(t) is not periodic - so doesn't that mean synchronization has to predict what f(t) will be?

Or are you really talking demodulation? (And possibly a modulation after that)
 
  • #7
Will you sample with the electrical probe, at every positive zero-crossing of the RF generator, or less often?
How often can the electrical probe take a sample?
 
  • #8
K-Manu said:
TL;DR Summary: RF source synchronization method

phase locked loop: it is commonly used for synchronizing the high-frequency signal, but as I know it is proper for a periodic AC source, and mine is an aperiodic source.
According to my limited understanding, in a generally simple system, only two periodic signals can be synchronized. This method uses the output of the phase comparator for feedback control, ultimately changing the frequency and phase of one periodic signal so that it is the same frequency as the other periodic signal, and the phase difference of the two periodic signals also remains constant. In this case, the phase comparator can be analog or digital.

Synchronization of non-periodic signals is beyond my knowledge. I think this should belong to a higher level of scientific research, and I would like to know more.

If you want to control the timing relationship between a periodic signal and another non-periodic signal (or between two aperiodic signals) in a simple system , I think it can simply be called a signal triggering process, which is different from two periodic signals being completely synchronized.

K-Manu said:
TL;DR Summary: RF source synchronization method

Edge-controlled phase detector: Detected phase difference between two sources and applying it to a delay generator would be the idealized method. But I could not find proper user-friendly products (IC is not proper because I'm poor at that)
I don't know the actual specifications and control methods of your RF power generator. Is there an input to control its frequency or do you just want to use a trigger signal to have it provide power to discharge the gas once

Regardless, if you want PLL control, using an IC seems necessary unless you have the ability to make a PLL control circuit using discrete components. :smile:
 
  • #9
Of course, we can easily generate two synchronized periodic or even aperiodic signals by passing one signal through a delay generator to trigger another signal, but this does not require a phase locked loop.

If we need to change the frequency and phase of an existing periodic signal to synchronize it with another periodic signal, we can use phase locked loop, which requires a process of phase comparison and negative feedback to complete the task.

They are two essentially different processes suitable for different applications.:wideeyed:
 
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FAQ: How to synchronize the RF source having delay over time?

What is the primary cause of delay in RF sources over time?

Delays in RF sources over time are primarily caused by factors such as temperature variations, aging of electronic components, and environmental interference. These factors can affect the stability and synchronization of the RF signals.

How can temperature compensation help in synchronizing RF sources?

Temperature compensation can help by using temperature sensors and compensation circuits to adjust the RF signal parameters dynamically. This ensures that the signal remains stable and synchronized despite temperature fluctuations.

What role do phase-locked loops (PLLs) play in synchronizing RF sources?

Phase-locked loops (PLLs) are critical in synchronizing RF sources as they lock the phase of an output signal to a reference signal. This helps in maintaining a consistent phase relationship, thereby reducing delays and enhancing synchronization.

How can GPS-based synchronization be utilized for RF sources?

GPS-based synchronization can be utilized by using the highly accurate timing information provided by GPS satellites. RF sources can be equipped with GPS receivers to synchronize their internal clocks, ensuring precise timing and minimal delay.

What are the best practices for minimizing delay in RF communication systems?

Best practices include using high-quality components, implementing temperature compensation, employing phase-locked loops (PLLs), utilizing GPS-based synchronization, and regularly calibrating the system. Additionally, shielding the system from environmental interference can also help in minimizing delays.

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