Unanswered Questions
9
votes
2answers
2k views
How to implement critical sections on ARM Cortex A9
I am porting some legacy code from an ARM926 core to CortexA9. This code is baremetal and does not include an OS or standard libraries, all custom. I am having a failure that appears to be related ...
6
votes
0answers
455 views
Typical zero sequence data for 80MVA transformer
I need to model a 80MVA transformer 132/33kV built in 1973. There is very little information on this transformer but I need to populate certain values in the model.
Where can I find typical zero ...
5
votes
0answers
90 views
GaN pulsed operation
Does anybody have experience biasing and pulsing a microwave GaN HEMT? I've just ordered a 10 Watt S-band transistor. I know all about bias sequencing. This application is pulsed. I've read about ...
4
votes
0answers
53 views
Is it safe to separate the power supplies for sensor, buffers, and ADC?
In the LT1054 datasheet it talks about needing a bjt to avoid pulling the VOUT positive with respect to GND (datasheet page 5 Vout (Pin5): http://www.linear.com/docs/2309).
Now I am powering an ...
4
votes
1answer
98 views
Mic5158 does not regulate
Refering to this post, I changed mic5156 to mic5158 (datasheet) and
this mos.
I wired it several times as the datasheet shows but I can't get any regulated
voltage.
In order to understand what ...
4
votes
0answers
168 views
Buffer for 5V, 500ps to 10 ns pulses
I am trying to make a buffer for short, 5V pulses.
The pulses are negative (form 5 to 0 V) and last for 500 ps to 10 ns (Half maximum, full width).
The load is capacitive, around 50pF, and as close as ...
4
votes
1answer
204 views
How much can BJT parameters (particularly beta) vary for Monte Carlo analysis
Background / Requirements:
I'm designing a typical Class AB amplifier using diode-connected BJTs to achieve the biasing. I have a requirement to keep the total quiescent current at room temperature ...
4
votes
0answers
3k views
Msp430g2553 i2c communication library with itg3200 gyroscope
I've been creating an I2C library for communicating with ITG3200 gyroscope for MSP430g2553 experimental launchpad. I still have slight problems with sequential reading and the signed values but I'm ...
4
votes
1answer
286 views
Error interfacing GSM sim900 with atmega32
Hi all I am trying to interface GSM SIM900 with atmega32. I have a written a code in which if a user press a push button, a call will be made to a pre defined number. If we want to change the pre ...
4
votes
3answers
313 views
How to control a cellphone using an Arduino?
I wish to control a classic cellphone using an Arduino Nano by connecting the cellphone keys to digital pins, and switch them using a program that I will put on the Arduino. The idea is to make a ...
4
votes
3answers
386 views
Calculating reflections
I just solved a problem in my homework. I had to calculate the reflection waves and I was given the following data:
Resistance
R0 = 120 Ω line impedance
Ri = 90 Ω resistance at input
Rb = 1 kΩ ...
3
votes
1answer
92 views
Why can't a control unit detect this 12 volt signal while my multimeter can?
I work as a contractor installing stop request signs on busses. The stop request sign is basically a device that illuminates when a rider pulls the stop cord. When it is pulled, 12v is sent to the ...
3
votes
0answers
91 views
Will FCC EMC tests need to be redone?
In light of the new FCC rules that Chinese (and all non-MRA) labs will no longer recognised in July and all EMC tests need to be done at FCC-authorized Telecommunications Certification Bodies, for FCC ...
3
votes
0answers
36 views
Help with multiple receiver channels and single storage architecture
I want to build a datalogger that has multiple receiver channels that run on serial communication protocol RS232 and then collect the information from the channels in a single storage that would be ...
3
votes
0answers
61 views
TMS320 Floating Point (Texas Instruments DSP from '98)
Background
Is there anybody here who is an EE with programming experience who has worked with the Texas Instruments TMS320 C3X-series DSP? I am currently doing some work with the C3X for a project. ...
