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# 125 Khz

41 Threads found on edaboard.com: 125 Khz

Hello. I wanna read 125 khz proximity card. I added EM4095 in my circuit. But I have noticed that EM4095 supply voltage is 5V. I wanna use same chip but runs logic level 3.3V and cheap. Can you suggest 3.3V 125 khz transmitter. Thanks

## capacitor selection for antenna tuning

What frequency? The term "proximity card" refers to the older 125 khz devices as distinct to the newer 13.56 MHz contactless smartcards. You can also use diodes used as a varicap for fine tuning which increase in pF size with power rating but wide tolerance for any diode.

## ofdm bit rate with various subcarriers and symbol rate

I like do some math. a. 20*1*48*125K*4=480M. b. 20*1*24*125*4+20*1*125*6=600M

## Can't make oscillator with CMOS inverter

Hi all guys, I am trying to make an oscillator using CMOS inverter for quite some time and it won't oscillate at desired frequency. I want to make 125 khz oscillator using following schematic (the element values are not relevant for desired frequency): 111933 The circuit simply won't oscila

## can any body explain to me how can this circuit produce an alternating current

I presume "PWM" means in this case that a PIC timer is used in PWM mode to generate a square wave of fixed duty cycle. We get a 5V square wave at the MOSFET drain (or less, depending on the LC values). It will generate an AC current through the LC circuit. If LC is tuned to 125 khz, it's mostly a 125 khz sine current.

## RFID &PIC 18f452

Can someone help me with MikroC program for interfacing RFID reader(serial,125 khz) with pic18f452

## RFID reader & tags ...doubt

The HF (13.56 MHz) reader can only communicate with HF tags. However, there are HF tags which can work at 125 khz or 900 MHz at the same time.

## Direct Digital Frequency Synthesis with fractional steps

Hi, I implemented a integer-N pll based frequency synthesizer but it takes 2m second to lock at desired frequency. But my adviser didn't accept it. Now I want to use DDFS but my project's details are as below: 1- output frequency between 880 MHz and 912 MHz 2- reference frequency 880 MHz or 900 MHz 3- step size 125 khz And the question i

## EAS+RFID Tag Configuration

Diffferent RFID standards use different frequencies, e.g. 125 khz, 13.56 MHz and 900 MHz. RF EAS tags are simple passive LC resonators, see Wikipedia article: These tags are essentially an LC tank circuit that has a resonance peak anywhere from 1.75 MHz to 9.5 MHz. The most p

## Does anyone know on how to initialize ADC on ATMEGA128 ?

I tried to init like this : void adc_init() { // enable ADC, select ADC clock = F_CPU / 128 (i.e. 125 khz) ADCSRA = (1<

## COSTAS loop implementation using System Generator tool (ISE)

I have developed a simple costas loop for BPSK demodulation. It is working fine for 8Mbps data rate BPSK. The overall sampling freq is 125 MHZ. Inside the loop, the corresponding FIR and loop filters are running at 25 MHz. The lock range achieving is +100 khz to -100 khz of centre 30 Mhz. Now, I am updated the same for QPSK demodulation. (...)

## Initializing signal with 125Khz.

Hi, I have small problem with generating sine wave initially with 125 khz. This seems very simple but it took lot of time from me but i couldn't figure it out what is the problem. I am using CodeVisionAVR compiler. I am using ATmega32-A micro controller, AD9833 programmable wave form generator to generate sine wave. I have written the fallowi

## RFID problem with pic16f

Hello guys ,, I have a problem with my project, its a rfid reader (125 khz) connected to pic16f877a with a LCD (works fine without rfid ).. after I connect them ,, I only see the cursor down , but nothing happens when I try to make it read the tags! my code (micro c): unsigned char uart_rd; unsigned char data; unsigned char temp

## RFID frequency identification

If the antenna has many thin wire turns it may be a system working around 125..145 khz. Many turns are requried to get the antenna coil in resonance with a capacitor. The transmitting antenna (reader antenna) also has many turns. If the antenna has about 10..20 turns and the transmitting (reader) antenna has one to some turns, it is very likely

## ML‐91 NVIS antenna and design the roof rack antenna

I have to design a NVIS roof rack antenna for the following specifications. Frequency range: 3.3 ‐12.5 GHz. Power rating: 125 PEP Receive bandwidth: 45 khz at 3 GHz and 290 khz at 12.5 GHz. Tuning method: Continuously variable tuning capacitor. Drive Method: Microprocessor controlled precision stepper motor. Dimensions: (...)

I specifically need a total analog circuit... As far as your RFID is transmitting data according to an existing 125 khz standard, it will go digital. Thus a RFID system can't be totally analog.

## Qualitiy factor of an inductor

Dear friends, I designed loop antenna for my RFID and wanted to fin out its inductance, quality factor and DCresistance. I used LCR meter and found out that L=742\mu H and Q=19.63. all measurements were made at 100khz and that is fixed for the device. Can anyone tell me how to find the Quality factor at 125khz since t

## How to read and write to an unknown RFID chip

First you have to identify the RFID standrad implemented by the chip. ISO/IEC 14443 (13.56 MHz) would be a promising candidate, but is may be also a low frequency (e.g. 125 khz) standard, or some less common protocol. A 13.56 MHz standard would be most simply identified by trying to read out the chip with a multiprotocol RFID reader.You may want to

## How to start IRFP250 with PWM?

Hello How to start transistor IRFP250 by the microcontroller PWM? Microcontroller PWM output frequency is 125 khz. This transistor must turn on 10 Power LED 1 Watt. This is a RGB projector. best regards

## help!!fsk 125kHz rfid reader circuit problem

I just considered, if the circuit can be slightly modified to achieve the same or even higher output at 9V supply voltage. But I stumbled upon a completely erratic dimensioning of LC circuits. If the L and C values are correct, both LC circuits have about 4 MHz resonance frequency, although the 4060 clearly produces a 125 khz square wave. The c

## LUT to change inputs of another module

Lets say I have two programs in Verilog, one the LUT and the other some logic circuit with a clock. Lets say in that circuit 'a', a1 is an output. a1 is input to the LUT and the output of the LUT is the new clock value for 'a'(clock is an input to 'a'). eg: if a1=2'b00, the LUT changes the clock to 125 khz from 1 MHz. How could I code this? (jus

## RFID Library system - schematics for a reader/writer

Hi .. I am working on a RFID Library system .. and i was looking for schematics for a standalone tags reader/writer .. I will use passive 125 khz tags .. It will contain a LCD to show read results ... And I will use pic16f877 and USB as interface ... I am not looking for a project to copy but for schematics and data to help us to do our system .

## Help for active RFID reader design...

ASA to all im trying to develop device that read active rfid card.(125 khz) any body know any ic wich reads rfid card and give data to my microcontroller.. or i have to design whole demodulation filter ckts by my own ????. Any data, documnent, web link from you will very helpfull for me. thx in advance

## low frequency flat amplifier

I need a circuit for an amplifier with the following specifications: 1- frequency band : 25 khz-125 khz 2- Gain: 10 dB (not important) but flat response in the band. 3- mathing: input=50 ohm , output= 50 ohm (for coaxial cable connection to antenna and ...) i tried with OP07 (operational amplifiers) but it has problem. thanks.

## RFID Reader 125khz, Power boost problems?

Hi everybody, I 'm developping an RFID REader working at 125 khz,The RFID reader must read an TAG (Transponder) From ALLFLEX (They developp Transponder for animals), the distance between TAG and reader should be 70~100cm. I look at lot of documentation from philipps,ATMEL,ElectroniqueMArin,....etc But I think the problem will be on the powe

## Help on Sound pressure Levels of sine waves

Hi, I am doing experience on measuring the SPL of sine waves generated from computer by a simple Sound Level meter using the A weighting parameter , The expression of the resulting signal is 1*sin(2*pi*f*t) and f varying from 125 Hz to 8 khz the results are : 125:: -> 54 dB 250 Hz:: -> 69.9 dB 500Hz:: -> 86.3 db (...)

## Simulator for RFID 125 kHz antenna

Hello, it is the first time that I write on this forum. I must plan the antennas of the reader and the tag of a rfid system at 125 khz; Which simulator advised to me?Is HFSS adapted? with regards

## Build loop PCB antenna for EM4095 RFID Reader

Hi, the antenna frequency is 125khz. Regarding the solution I didn't succeeded to calculate L and Q factor. Best regards.

## 125 khz carrier signal generation

hi, i want to generate 125khz carrier signal for rf reader.... can i do that using pic18f452????how?? or i need to use extra counter??

## 125-kHz receiving antenna for a circuit

If you are interested in a 125-khz receiving antenna, it is attached. If not then ask again.

## tag Sokymat for 125 khz

Hello, I.m designing a rfid sytem and now I´m designing the readers antenna. Im using a sokymat unique tag for 125 khz. But I need some information of the tag´s antenna to maximize the read range. Where can I get the information about the antenna of this tag??? Does a desig guide for this kind of tags?

## How to perform FSK modulation for data transmission through power line

Hi, You can use a NE567 for demodulation and use a PIC microcontroller for FSK generation @ 125 khz. But you can also use ST chip :-). Paul.

## What factor is responsible for the range of RFID?

Hi, You have different kind of passive RFID card all based on different technology. You have PROXIMITY CARDS for 125 khz and 13.56 MHz based on ISO14443 max distance : 4 upto 10 cm (MIFARE 13.56 MHz) You also have VISINITY CARDS for 13.56 MHz based on ISO15693 upto 1 Meter MAX. You also have 914 MHz and 868 MHz cards that can work on dista

## Long range rfid - 125 khz

Hi i looking for project , ideas for long range passive rfid 125 khz - long range = about 100 cm. I want to read word tag unique with manchester encoding. any ideas ? i found some information on internet - i buy oem reader but all time range is too small thanks Robert

## block diagram of rfid reader

Hello, you have to understand the communication techniques used with RFID. For 125 khz it may be according ISO/IEC 18000-2. See the protocol-spec. in attachment. It has been available from if I remember right. Regards, Frank

## For those who have used the U2270B

Hi, Cypress Microsystems released a new chip for 125 khz RFID systems(T55xx Atmel/Temic type transponders and EM4100/02). It does much more than U2270b.(e.g programmable , decodes data for serial comm....)and they also provide PDIP , SSOP , SOIC packages(All CY8C27443 packages)

## What is the RFID? Please provide a sample circuit

I have done some experiments trying to implement RFID in range 125 khz. I will tell you: - with an antenna Accura GP20 10cm diameter aprox. I read tags type glass 13mm in the distance of 10 cm. - with an handheld device MINEC 4x I read and write tags (glass type 13mm or disk 50mm) only if I touch the tags with the device (0 distance of reading

## I need help on the issue of asynchrnous serial data transfer

Hi, I've been working with 125 khz, 13.56 MHz and 915 MHz RFID readers. Which one do you want to use? Where do you plan to connect your reader to? I connected them to MC AT89C2051, AVR90S8515, ATmega8515, and to laptops & palmtops. Regards, GeorgeM

## A Low Power RF ID Transponder

here is some info on 125 khz RFID system design.