英語 での Loop bandwidth の使用例とその 日本語 への翻訳
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Outside of the loop bandwidth, the VCO noise dominates.
Therefore, response time is limited by the control loop bandwidth.
The loop bandwidth is close to the switching frequency itself.
The benefit of increasing the loop bandwidth is a shorter lock time.
As part of the control loop, the microprocessor affects the loop bandwidth.
Also, the PLL loop bandwidth should be minimized wherever possible.
The minimum rise time of the line orload step is determined by the loop bandwidth of the controller.
A 1MHz controller should have a loop bandwidth of less then 1⁄2 the switching frequency, or 500kHz.
Additionally, the value of the output capacitor can greatlyaffect the converter's output transient response and the loop bandwidth.
For a fixed amount of loop bandwidth, the triangle pattern can support a larger dither frequency.
Tradeoffs are needed between PLL phase detector frequency, loop bandwidth and spurious outputs.
Within the PLL's loop bandwidth, the PLL can successfully track and filter the LDO noise, reducing its contribution.
That is, if the output frequency is 2000.01 MHz and the loop bandwidth is 50 kHz, the IBS will be strongest.
Generally, the loop bandwidth should be set smaller than one-tenth of the PFD frequency, and the safe range for phase margin is from 45° to 60°.
PLLs use a negative-feedback control system similar to that of an amplifier,so the concepts of loop bandwidth and phase margin apply here as well.
High loop bandwidth provides fast transient response, resulting in less required output capacitance and allowing for all-ceramic capacitor designs.
The result of these bias-voltage changes and the pushing factor is unwantedmodulation sidebands that fall outside of the PLL synthesizer's loop bandwidth.
With the PLL loop bandwidth set to 10 kHz, a PSR of about 90 dB is possible; with a loop bandwidth of 80 kHz, the PSR is 50 dB.
This has just 90 degrees of phase shift above its corner frequency,allowing much higher loop bandwidth before the overall phase delay reaches 360 degrees.
The wider that the loop bandwidth is set, the less susceptible the circuit will be to RF coupling since the closed loop will attenuate the coupled noise.
The voltage-mode control architecture and the voltage-error amplifier permit a typeIII compensation scheme to achieve maximum loop bandwidth, up to 200kHz.
Because the PLL multiplies noise within the loop bandwidth by the PLL division ratio(~30,000 for an AMPS handset), the frequency synthesizer is very sensitive to noise from the TCXO.
Lock time is inversely proportional to theloop filter's cutoff frequency so increasing the loop bandwidth decreases the time it takes for a PLL to lock.
If settling time is critical, the loop bandwidth should be increased to the maximum bandwidth permissible for achieving stable lock and meeting phase noise and spurious frequency targets.
This function transforms the values of resistors and capacitors to the nearest standard engineering value, allowing the designer to rerun the simulation toverify the new values for phase margin and loop bandwidth.
Reference phase noise profile at 122.88 MHz. PLL1 relies on a high-performance VCXO andlow loop bandwidth to attenuate the phase noise of the reference, allowing the phase noise of the VCXO to dominate.
Appendix PLL divider value algorithm to find feedback and reference divider in a frequency synthesizer such that the highest phase dectector reference frequency is used,giving the widest possible loop bandwidth.
The loop bandwidth is generally set to 1/5 to 1/10 of the voltage-loop bandwidth in order to prevent interference with the voltage loop, which is sufficient for current balancing as slow adjustments are usually all that are required.
Thus, as the loop filter corner is pushed farther out, the integrated phase error of the LO signal is increased according to the following equation: Integrated Noise 10 x log(F2/F1)where F1 and F2 are the narrow and wide loop bandwidths respectively.
Block diagram of the AD9523-1. Many engineers think of dual-loop PLLs as frequency translators that reduce the reference input jitter by a fixed amount, but it is more accurate to think of them as low phase noise frequencytranslators whose performance is affected by each PLL's loop bandwidth and the phase noise profiles of the VCO/VCXOs.