11 Threads found on edaboard.com: Quartz Pll
In principle yes but the real technology differs. Up to ~500 MHz quartz crystals are used as resonators, other resonator types are used at microwaves. To stabilize the frequency, low-frequency crystal oscillators are used as reference, their frequency multiplied to control the high frequency VCO by phase-lock or other techniques.
RF, Microwave, Antennas and Optics :: 03-30-2015 21:03 :: jiripolivka :: Replies: 2 :: Views: 545
1 cycle =1000000 / in ?S
FOSC can be internal (inside the PIC) or external , use of a quartz or an external clock device generator.
for Other PIC18F you can active a pll multiplicator => FOSC*4 => 1 cycle= 1000000/ FOSC ?S
for executime time
Code operation take mainly 1 cycle ( it's explain why we divide FOSC/4)
Microcontrollers :: 02-04-2015 11:58 :: paulfjujo :: Replies: 3 :: Views: 538
the dividers are quite big according to the schematic. I would suggest to install instead of the quartz oscillator another VCO using a new 4046, which's output connect to the input of your pll's input.
Analog Circuit Design :: 08-30-2012 13:08 :: sztibi82 :: Replies: 1 :: Views: 487
I'm running a project on PIC18F46k22 with 20Mhz quartz crystal, In configuration I have selected :
1. HS Oscillator (high power > 16Mhz)
2. Oscillator 4X pll Enable - Oscillator multiplied by 4
Is now the system running at 20 x 4 = 80Mhz or is it at its maximum frequency 64 MHz (as described in datasheet)
I'm bit confused please rep
Microcontrollers :: 04-03-2012 23:45 :: garg29 :: Replies: 4 :: Views: 1464
The reference clock is usually quartz and n the motherboard somewhere. There will be a pll IC nearby which multiplies it to produce the various signals used around the board. One of these will go to the processor which has it's own internal pll to further increase the speed it runs. It wouldn't be feasible to run a fast clock along a PCB (...)
General Computer :: 07-27-2011 04:09 :: betwixt :: Replies: 4 :: Views: 5484
I am about to finish my 80 MHz quartz Crystal VCO, but I am not confident on Jitter's results. Please try to answer these questions, as fast as you can, as I have the tape-out in August of the full pll:
1 - For the VCO circuits (autonomous circuits), which jitter measurement type should I use: FM or PM (I am using FM)? I think we should u
Analog Circuit Design :: 05-12-2011 03:55 :: netbug :: Replies: 0 :: Views: 910
Stability is not a function of modulation type !
If you need it to be stable, use a quartz crystal in conjunction with a pll.
Analog Circuit Design :: 12-04-2009 14:12 :: betwixt :: Replies: 1 :: Views: 1037
I can't find the capacitance value to use for a PIC18F MCU clocked at 40MHz.
I see that from 1MHz up to 25MHz Microchip is proposing 15pF. But no mention for 40MHz.
Anyone can help?
Microcontrollers :: 04-14-2008 11:44 :: jabidof :: Replies: 3 :: Views: 2409
Hi, I need wary simple telecommand i any frequency. Only thing that it matters is that there is no pll or any delay element like quartz filters. I need it in one direction so it would be one transmitter and one receiver. It is necessary to delay time from moment i enable transmitter to time i detect change on digital out be constant, and strive tow
RF, Microwave, Antennas and Optics :: 04-08-2008 10:25 :: ADRENALIN2003 :: Replies: 0 :: Views: 594
just another word: It's interestig to plot the phase response by means of a pll. In this technique the quartz is used as a Phase shifter whose phase depend upon frequency. Sending into the quartz a smal sinewave at different frequency by varying the pll programmed freq and analyzing the difference on the locked phase you con (...)
Analog Circuit Design :: 12-16-2004 06:12 :: mrm :: Replies: 11 :: Views: 4271
Go to this site, ask for a sample, do your design, check the output level and if is necessary put an amplifier. Beware this is a VCO and the frequency is not very stable if is not part of a pll.
If you are looking for a stable LO, the cheapest way is to start from a quartz frequency (e.x. 101.6
RF, Microwave, Antennas and Optics :: 05-30-2004 17:10 :: vfone :: Replies: 6 :: Views: 2028