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280 Threads found on edaboard.com: Adc And Noise
In addition, there are two flavor of delta sigma adc. Discrete time and continuous time. Continuous time has inherent anti-aliasing.
Without thinking too hard about this, I think you've got a problem. If you lower your gain and, consequently your noise, you're also lowering your resolution, so I don't think you've gained anything. In other words, if you cut your noise by a factor of 2, you're also cutting your resolution by 2. If I'm reading correctly, if you have 2V (...)
Hello! Some hints on how to start: - 0 ~ 30 mA with a resolution of 1?A implies a 15 bit converter. You can find many 16 bits. - As for the circuit, you have to use an op amp and set its gain to fit the input range of your adc. - In the case you have enough noise (usually it's not a problem), and if your signal is slow (...)
Hello, I am writing a C code using mikroc and PIC16F676. Here is the code, #define Dl_Relay PORTC.B2 #define Relay_1 PORTC.B1 #define Relay_2 PORTC.B2 #define Relay_3 PORTC.B3 #define test PORTC.B1 char i=0,j=0,cycle=1,Flag=0,biggest_val; unsigned int mains_val=0,a=0,b=0,k=0,d=0,Average=0; void peak_detector(){ wh
What is the minimul level of a I/Q signal at the input of tha adc of a SDR that is required to demodulate the signal? In the document "Software defined radio for the masses IV" is is stated: "For a weak signal to be recovered, the minimum analog gain must be great enough so that the weakest signal to be received, plus thermal and atmosphe
Hi, your AD7655 power supply specification is 4.75V ... 5.25V But USB power supply specification is 4.4V ... 5.25V (wikipedia) (I thougt USB Spec tells 4.5V ... 5.5V, but I may be wrong) My experience with USB supply is worse. Especially when drawing more than 100mA, use some longer cables and the use of passive HUBs. Especially cheap USB cables
1.) An adc is known for its horrible NF, say 30dB. A conventional receiver would add LNA & gain in order make the overall NF much lower (through Frii's), say 5 dB. However, these gain stages add noise themselves. So if I assume the maximum input swing of my adc is 2Vpp (13 dBm) and I can pick my input power level of the recei
Dear All, Could you please tell me what's the relationship between OSR and ELD in continous-time sigma-delta adc? and why lower OSR is more sensitive to ELD? Thanks a lot! best, Ken
Hi, when we calculate the SNDR or ENOB in adc, we add all the noise together, i.e., quantization noise, kT/C noise, DNL noise, etc. Let's say DNL is +/- 0.5LSB and LSB=1mV, what's its equivalent noise in terms of mV? Thank you.
pic 16f877 adc is 10 bits only. it won't be sufficient for mpx4115 which returns you 0 to 5 volts to measure 0 to 1150mbar pressure you will get at best less than a mbar resolution ( not counting on noise and interferences) you need another adc (like MCP3421 18bits) or you need an analog circuit to interface the mpx to the (...)
hi my friends i have problem with ground loop noise .what can i do? this is my circuit: Hi, A simple way to solve this problem, is STAR Topology : All of Ground Nodes connect together in one point only. in Your Circuit i think the best po
Hi I have written Matlab script for BPSK modulation. The way my code works is as follow: series of 0 and 1----> NRZ data (continuous rectangular pulses with amplitude -1 and 1)--->multiply by carrier----> add noise--> multiply by carrier---> integration--->detection---> Bit Error collection? I would like to know can anyone tell me (...)
Using a voltage divider to 50 Ohms and coax feed to Spectrum Analyzer on analog preamp out may help isolate noise by viewing spectral density. Examine noise above f/2 sampling rate also. - - - Updated - - - I recall designing something with 12 bit adc using Burr Brown Hybrid in 70's and had no difficulty gett
Hi, using VCC as reference.... Are you sure it is stable enough, free of noise, filtered? It seems you built a motor control with PWM. Then there are high power pulses. I recommend to start conversion at a dedicated point of PWM. Then the values schould be stable and reliable. Do you have a picture of your circuit / PCB layout. Especially powe
The most common reason for the PIC adc fluctuating is that the voltage reference has been tied to the supply rail and you have noise on the supply rail. A large capacitor on the decoupled VREF should cure. Another cause could be that the input voltage is at to high an impedance (should be less than 10K or that the input voltage is noisy.
Hi, it depends on your power supply filtering, but usually using a linear power supply is better and you can achieve better results. Normally in microcontrollers there is no internal ripple or switching noise rejection, (because it needs large capacitors or inductors (in Chip Scale)) , and usually they have an extra power pin for (...)
I have a Kinetis MCU design that senses temperature from a PTD using the internal 16-bit adc. It also has a UART that I use as a console port for development. When the UART is plugged in (to a FTDI cable), the adc input is very stable with all samples within a 3 unit range. When I unplug the UART, the samples are much noisier with a range of about
I have written a code for 8255 PPI but I am having three problems. 1. In the code comment out all code inside the while(1) loop and un-comment lcd_string(*msg); which is before while(1) loop and Compile and run. LCD displays proper string if there is no character repeated i.e., string "EDABOARD" is printed as EDABOARD but (...)
I would use a MCP9701 or MCP9701A from Microchip. They are inexpensive, cover the temperature range you want with sufficient accuracy and best of all, produce an analog output voltage which is already scaled to suit a standard adc. They can also drive large capacitances so you can easily filter out any noise picked up on (...)
In theory, a pH probe produces about 59 millivolts (mV) per pH unit, and at pH 7 (neutral pH) the probe produces 0 volts. A typical pH probe conducts 1~2nA thus represents an impedance ~ 600mV/1nA=600M approx. Naturally a FET input Op Amp is needed such as a TL071 but the INA116 gives better CMRR for stray Efield noise. You must choose a bette