Abstract: Combining the advantages of digital frequency synthesizers (DDs) and integrated phase-locked loops (PLLs), high-resolution, low-spur, wide-band frequencies composed of DDS chip AD9954 and integrated phase-locked chip ADF4113 are developed and designed. The synthesizer and the frequency synthesizer were analyzed and simulated. From the simulation and test results, the frequency synthesizer reached the design goal. The frequency synthesizer has an output frequency range of 594 to 999 MHz, a frequency step of 5 Hz, and a phase noise of -91 dBc/ The reference signal of the DDS is generated by a crystal oscillator whose frequency is fref. The signal frequency of the DDS output is fDDS, and the frequency value is controlled by the frequency control word (FTW). The reference signal of the phase-locked loop (PLL) is driven by the output signal of the DDS. The output frequency of the VCO is output by the charge pump (CP) of the PLL chip and is controlled by a low pass filter (LPF). The output signal of the frequency synthesizer is the output signal of the VCO. The frequency synthesizer provides a control signal through the microcontroller to change the division ratio of the FTW and PLL in the DDS. The relationship between the VCO output signal frequency and the DDS output signal frequency is: The output frequency of the DDS is controlled by the frequency control word K and has: Where: M is the number of bits of the phase accumulator of the DDS; fref is the internal clock of the DDS. Thus, equation (1) can be written as: In the structure shown in FIG. 1, since the DDS module has a higher frequency resolution, it can be seen from the equation (3) that the theoretical output signal has a higher frequency resolution than the conventional structure. The design has a crystal frequency of 400 MHz and a PLL divider ratio of 27. It can be known from the calculation of equation (3) that the frequency source can achieve a frequency resolution of 5 Hz. The output frequency of the DDS is 22 to 37 MHz, so the system output frequency ranges from 594 to 999 MHz, which meets the design requirements. L.2 circuit implementation For the DDS module, the AD9954 chip is used to generate the low frequency reference signal. The AD9954 is the latest AgiIeRF synthesizer from Analog Devices, with a 32-bit frequency control word. At a clock frequency of 400 MHz, the output frequency resolution can reach approximately 4.7 & TImes; 10-5 Hz with a 14-bit programmable phase shifting unit. The chip uses advanced: DDS technology, integrated 14-bit high-performance DAC. The DAC has excellent dynamic performance with phase noise better than -120 dBc/ The PLL module is especially important in this design structure. The ADF4113 phase-locked loop chip is used here. The digital phase-locked frequency synthesizer ADF4113 developed by Analog Devices has a maximum operating frequency of 4 GHz and is mainly used in the field of radio frequency to form a digital phase-locked loop to lock a certain frequency. The internal resources of the circuit mainly include programmable analog frequency dividers: 8/9, 16/17, 3z/33, 64/65; programmable 14-bit reference frequency divider; programmable RF signal divider; 3-wire serial bus interface; analog and digital lock status detection. The chip's highest phase-detection frequency is 55 MHz and the chip's noise floor is -171 dBc/
LSZH cables is the
abbreviation term of (low smoke halogen free) low smoke zero halogen electrical cables.FR is for flame retardant power cables, also for the short term of Fire Resistant Power Cables. The smoke
released by these cables is non-toxic when
fire happens. Therefore they are
applicable for public places to protect instruments, equipments and people from
potential harm.Fire resistant Power Cable will still keep the electrical power
on within certain time in case of combustion.Flame retardant power cable may
produce low gases and smoke after
combustion.These cables are generally used in population-concentrated public places to have better fire safety
and rescue capability.
Specification
Conductor:99.99% oxygen free
copper or aluminum
Insulation/Sheath:
LSZH FR formula added
Rated Voltage:≤35KV
Packaging: wooden
steel drum, wooden/paper/plastic reels
Main advantage
l Low or
no halogen acid gas release
l Excellent
resistance to weather (-30℃ to 105℃)and fire
l Withstanding high
voltage and current stressing
l Good
elasticity and stickiness, long life time
Application
l High-rise
building
l Hospital
, Large-scale library,Gym ,Hotel
l Bus
station or railway station, Airport , passenger waiting room
l Cultural
heritage building, nuclear power plant,important
military facilities
l Subway
,underground shopping mall
Classification
The application of
LSZH power cables are classified into 4 level based on using features, fire
risk and difficult for evacuation and life-saving.
Application
Flame Retardant Class Choice
Superior
Class
A
Grade
1
Class B
Grade
2
Class
C
FAQ
Q: Are you a factory or trading company?
Q: Can I visit your
factory?
A :Yes! You are welcome to
visit our factory for further detail check.
Our factory is located in Minqing,Fujian.You could choose to fly
to
Xiamen/Fuzhou International airport. And tell us your flight No. We will arrange to pick you up
if you like.
Q: May I buy samples from you?
A: Yes! You are welcome to place sample order to test our superior quality and services.
Q: Can you put my brand name (logo) on these products?
A: Yes! Our factory accepts to print your
logo on the products.
Q: May I know the status of my order?
A: Yes .The order information and photos at different production stage of your order will be sent to you and the information will be updated in time.
Please welcome to
get in touch with us for further information about catalogue, production and
price list. Will response as soon as possible. OEM service is available based
on legal authorization. And you are also very welcome to visit our factory by
mutual schedule check accordingly.
LSZH FR Power Cable,Lszh Fr Sheath Power Cable,Power Station Control Cable,Low Smoke Control Cables Fujian Lien Technology Co.,Ltd , http://www.liencable.com
A : We are a manufacturer. We are professional in
developing and producing electrical wires and cables since 2001.