agoetz

7 ms·

1.
by agoetz 6y ago
Another benefit of biased representation, is that it makes error values extremely noticeable. It is common in automotive situations to reserve part of the representable range to indicate error or SNA (signal not available) conditions. If yo
2.
by agoetz 9y ago
Most RTCs do use the same crystals that are in wristwatches, which is actually the source of their error. The tuning fork crystal design used in wrist watches has a parabolic temperature coefficient, which means that the clock is only reall
3.
by agoetz 9y ago
> Embedded systems, IMO, must be deterministic, reliable and consistent. This is the definition of a hard real-time system. In most of the literature, 'embedded system' is a broader term that just means there is some compute em
4.
by agoetz 10y ago
Actually this article is talking about mild hybrid technology: Which is about upping the voltage for traditional non hybrid vehicles from 12V to 48V, giving them some hybrid like features on the cheap.
5.
by agoetz 10y ago
SW Solution: 1. Store embedded system state in data structure. 2. Calculate a checksum for that data structure. 3. Verify that checksum is correct. HW Solution: Lockstep Execution/ECC memory, etc.
6.
by agoetz 11y ago
If you try to estimate power spectral density using the intuitive unbiased estimator (the DFT), you are going to have a bad time. A vanilla periodogram has very high sideband leakage, which means that the energy of the signal at a single fr
7.
by agoetz 11y ago
Claiming that the FT is not necessary for digial audio is like claiming that the you don't need the rocket equation in order to build a missile. Sure, its technically possible, and yes, there were probably early pioneers that forged ah
8.
by agoetz 11y ago
Yes. Reformulate the systems transfer function into a state space representation, and then solve the algebraic ricatti equation to find an optimal gain matrix. This is know and the LQR problem. http://en.m.wikipedia.org/wi
9.
by agoetz 11y ago
The apollo guidance computer actually used a sophisticated software interpreter for most of its code. Not just a "computational loop with no branches" http://en.wikipedia.org/wiki/Apollo_Guidance_Computer#Soft
10.
by agoetz 11y ago
OSEK is a an industry standard rtos that is used by almost all automotive players. It is specifically designed for use in the automotive environment. Toyota actually claimed to use an OSEK compliant rtos, but it later surfaced in this lawsu
11.
by agoetz 12y ago
Modern EPA requirements mean that it is impossible to design a compliant off highway commercial vehicle without relying on advanced electronic process controls. Your grandfather's tractor might be repairable with baling wire, but it al
12.
by agoetz 12y ago
Adding a new sensor to monitor the fuses would not be cheap:first off, you have to have signal conditioners for the a/ds that can handle esd transients, and >60 v load shed events. In addition, the existing design probably just has
13.
by agoetz 12y ago
Signal conditioning is still an important part of EE design. Not all signals are TTL level and unipolar. For example, this appnote[0] uses a Delta-Sigma converter to digitize a load cell, with the ability to "detect one sheet of copier
14.
by agoetz 12y ago
Generally the system will fall back to a 'limp home mode' running on a simpler algorithm on a watchdog microcontroller. See for example, Freescale's reference design for an airbag controller. http://www.freescale.c
15.
by agoetz 12y ago
Register renaming has been around since the 60's in the form of Tomasulo's Algorithm.
16.
by agoetz 12y ago
DRAM refresh circuit, not SRAM. The "S" in SRAM means that it doesn't need to be refreshed.
17.
by agoetz 12y ago
Not necessarily. The LM7805 has a maximum operating temperature of 125C, so a circuit can be operating nominally at a very high temperature.
18.
by agoetz 12y ago
Most of the magic doesn't come from the robots, it comes from the soldermask. Surface tension from molten solder will move misaligned parts by a surprising amount: http://youtu.be/N_195d7bP9M?t=3m10s
19.
by agoetz 12y ago
Bonus: Once you have a couple of data points from the tape method, you can extrapolate the emissivity of the toast itself and calculate a correction factor for your IR gun.
20.
by agoetz 13y ago
Make a circuit "digital" does not automagically make it more accurate, and you cannot "add bits" to a datatype to make your measurement more accurate. Before a digital circuit can process a signal, it must first be quan
21.
by agoetz 13y ago
FORTH comes to mind.