Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [latency]

63 questions
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What is the latency of an LED?

LEDs are known to have a very low, unnoticeable power-cycling latency, but how fast are they when measured? (nanoseconds?) In other words, how long does it take for an LED which is entirely off to get to its optimum brightness, and how long does it…
ayane_m
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Why does RAM (any type) access time decrease so slowly?

This article shows that DDR4 SDRAM has approximately 8x more bandwidth DDR1 SDRAM. But the time from setting the column address to when the data is available has only decreased by 10% (13.5ns). A quick search shows that the access time of the…
Arseniy
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Is there a correspondence between cache size and access latency?

Is there is a correspondence between cache sizes and access latency? All other things being equal, does a larger cache operate slower? If so, why? How much slower?
ivanmp
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What does a chip's propagation delay vary on?

When looking up datasheets on logic gates, propagation delay is usually shown as a range. Sometimes there's a "typical" value in the middle, but there's a min and max listed. On what does the range vary? Take this chip for…
AltF4
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Interrupt latency on a STM32F303 MCU

I’m working on a project that involves a STM32 MCU (on the STM32303C-EVAL board to be exact) that has to respond to an external interrupt. I want the reaction to the external interrupt to be as fast as possible. I have modified a standard peripheral…
K.R.
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Lowest latency out of the 802.11 Wi-Fi standards

I'm making a project using an Arduino and an ESP8266 module running the esp-link firmware - which gives me the ability to use MQTT for controlling the Arduino. I'd looked at something like an XBee module instead - but they're so damn expensive…
seanlano
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Why is the latency so high for Bluetooth audio?

Referring to this, the lowest latencies achieved in Bluetooth audio streaming are around 30-40ms. Given the fact that Bluetooth physical layer data rate is of around 2-3 Mbps and today's Bluetooth chipsets support sufficiently high processing power,…
Ashutosh
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How are LEDs timed? (How is the pulse latency measured?)

Please excuse the awkward phrasing of the question; it seems that LEDs have pulse latencies of nanosecond and sub-nanosecond durations. The question is, how was it possible to measure such precise increments of time? Is there ultra-high frame rate…
ayane_m
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How can I measure latency in a CAN bus?

Given a CAN bus with one master and 4 motor drivers, is there a way to measure the time between sending a command from the master (e.g. PC or PLC) and the execution of the said command (e.g. the motor moving)?
mohsen
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In an isolated SMPS feedback design, how could optocoupler latency be higher than the switching period?

I often see this in practical SMPS designs. An optocoupler & voltage reference pair is used for informing the controller section about the output voltage level. However, when I read the datasheet of the optocoupler in the circuit, I see that the…
hkBattousai
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Calculating latency for ADC chips

I am building a realtime based audio processing system that needs to sample 48KHz, 16bit audio, preferably with <0.5ms (the lower, the better) latency (Measured from analog signal -> data sampled and ready to be transferred to host). I will not need…
jseawright
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Can a barrel shifter be done combinatorially?

I was told that 66b/64b encoding in 10Gb Ethernet (10GBASE-R) requires a one-cycle barrel stage, which adds a necessary one cycle to the theoretical terminal latency. The Wikipedia page on barrel shifters states that A barrel shifter is a digital…
Randomblue
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How to pipeline an algorithm that not only has latency but also relies on feedback of the previous run?

Trapped in this problem for several days, I feel I can't think of a proper solution on myself. The problem is as below. Say, a source-input is streaming a sequence of A, denoted by A0, A1, A2, ..., Ai, ..., An. Now I'd like to do some action on A,…
xc wang
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STM32 Interrupt large latency

I am writing an STM32F303 application to digitize pulse signal amplitudes. There will be a peak detector, that can be reset by the uC pin, so I'm not expecting the uC to instantly digitize as soon as the pulse arrives, but I am still a bit confused…
sx107
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How to know the latency of an oscilloscope?

How can I know the latency of a digital oscilloscope in roll mode? By this I mean the time it takes from the signal reaching a certain value to the moment this value is shown on the screen, i.e. the time it takes for the scope to sample the signal,…
freejuices
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