48
votes
Accepted
How do GPS satellites refresh their clocks
Clock errors are not corrected, they are compensated in two steps.
1. Error determination
The GPS control segment uses reference receivers in well known locations to determine the actual orbital ...
- 1,815
20
votes
Is HSYNC required during VSYNC for VGA?
I can't find any trustworthy source of info to decide if VSYNC without
HSYNCs will work with all VGA monitors.
We only have to find one example that doesn't work to prove the negative, so...
I made a ...
- 56.8k
18
votes
Accepted
In one-way asynchronous serial communication, how does the receiver sync up its bytes?
UART timing for asynchronous data relies on knowledge of the data rate and having a clock that is typically 16 x faster. The top half of the picture shows how data is re-synchronised and the bottom ...
- 467k
18
votes
Accepted
Do crystal oscillators synchronize by themselves when coupled by supply voltage?
They can do.
When you want oscillators to lock to others like this, it's called 'injection locking', and is a useful but little-known technique. You would apply a bit more signal for injection than ...
- 171k
18
votes
Accepted
Does the SPI protocol specify how many clock pulses a master device should send to the slave?
The SPI master is not responsible for making sure that the slave's internal state machine gets 'enough' clock pulses. All the master is responsible for is one clock pulse per bit transferred to or ...
- 14.8k
17
votes
Does the SPI protocol specify how many clock pulses a master device should send to the slave?
The answer to any question about the SPI protocol is: there is no SPI protocol! It's the simplest possible way to transfer serial data, essentially just a shift register. Have a look at a typical SPI ...
- 7,969
16
votes
gps performance for synchronization
A GPS receiver creates a local replica of something called "GPS system time", which is a virtual timebase created from all of the clocks on the satellites and ground stations. This replica is integral ...
- 177k
13
votes
Need a method for synchronization of galvanically separated microcontrollers
Question 1: is there a method to do sampling correction/syncronization between the microcontrollers? Can you suggest a literature in this topic?
All STM32 ADC are capable of using an external trigger ...
- 23.6k
8
votes
Is there an efficient way for synchronising audio events real-time with LEDs using an MCU?
I am not fond of encoding command data as an analog signal in a digital file.
I think I would try something like encoding the lighting commands as text blocks in the lyrics block of the ID3 ...
- 73.1k
8
votes
Accepted
Need a method for synchronization of galvanically separated microcontrollers
Both of these work on the idea that there is at least some delay in the sample loop of the slaves, which could be adjusted to make the slowest slave catch up with the fastest. That is, that there's a ...
- 15.2k
8
votes
Is HSYNC required during VSYNC for VGA?
Yes, HSYNC is required. The monitor loses horizontal sync if you stop sending it, regardless of the state of VSYNC.
Or, if the receiving thing is not directly a monitor but some chip that samples ...
- 165k
8
votes
Accepted
Series thyristor circuit
You'll need equalisation for both static and dynamic behaviour.
As all of us are aware, the I-V and reverse recovery characteristics of the same brand/model SCRs are similar but not equal due to ...
- 38.1k
8
votes
How can I make a PAL sync generator without a microcontroller?
So, the good news is that if you read ITU-R BT.1700, which is the actual standard specifying the PAL signal, its timings and timing tolerances, the world is easier to implement than if you read the ...
- 98.4k
7
votes
Why do we need to synchronise asynchronous inputs in FSM?
As you already understand, your traffic light controller state machine is a synchronous machine. That is, it is driven by some clock in such a way that all combinatorial logic changes happen and ...
- 46.9k
7
votes
Accepted
How are two atomic clocks synchronized?
An "atomic clock" comprises two major subsystems: a precision oscillator controlled by a feedback mechanism that's based on some quantum-mechanical phenomenon, and a digital counter/display subsystem ...
- 177k
7
votes
Does the SPI protocol specify how many clock pulses a master device should send to the slave?
SPI is not a protocol in that sense which you mean.
It is only an interface to transfer bits automatically in serial fashion, most commonly in multiples of eight to transfer bytes between devices.
...
- 165k
7
votes
Accepted
10MHz reference vs 1 PPS vs GPSDO
A GPSDO is a way of providing a 10MHz reference. A GPSDO can be an external device, but some SDR devices are also able to "host" a GPSDO so that you don't need an external unit in its own ...
- 7,977
6
votes
How do GPS satellites refresh their clocks
say you have a clock at location A. How do you synchronize it with a clock at location B, which is far away from A?
You can do what NTP does. Roughly speaking,
send a request for current time at the ...
- 26k
6
votes
In one-way asynchronous serial communication, how does the receiver sync up its bytes?
UARTs (rs232) have a start bit (0) and a stop bit(1). see Andys diagram. But they use wire, and the noise is very low -basically none.
On a noisy link, this works very badly. If the start bit is ...
- 5,433
6
votes
Accepted
Is there an efficient way for synchronising audio events real-time with LEDs using an MCU?
Using an auxiliary DSP for decompression may make this difficult unless you limit yourself to constant bitrate files - if you need high time accuracy of the light events you may need to account for ...
- 33.6k
6
votes
Is there an efficient way for synchronising audio events real-time with LEDs using an MCU?
I once developed an application in which arbitrary events could be triggered by audio watermarks embedded in the sound. You could play the sound through tinny unamplified computer speakers at one end ...
- 177k
6
votes
Need a method for synchronization of galvanically separated microcontrollers
is there a method to do sampling correction/syncronization between the microcontrollers? Can you suggest a literature in this topic?
So, you'll need to synchronize their sampling clocks. That ...
- 98.4k
6
votes
Is HSYNC required during VSYNC for VGA?
If you have a receiving decoder you get to do whatever you want: it’s no longer VGA, it’s a digital video link. You could for example produce H sync all the time (with SPI CS, say) and encode the data ...
- 56.1k
6
votes
Series thyristor circuit
I randomly have a Velonex 510 Ring Generator, which uses an SCR stack. Here's an internal view:
As you can see, they have a stack of six (optionally seven in another model, it would seem) SCRs in ...
- 43.8k
5
votes
How to synchronize a generator on the electrical grid?
I have done this with multiple 500KVA truck mounted machines on a festival site back in the day, if goes something like this:
Set the no load voltage of the two machines to be within a volt or so.
...
- 17.6k
5
votes
Accepted
Why is the CAN bus always busy (microcontroller)?
There are usually two causes of this:
The bus terminators are not installed. The 120 Ω terminators at each end of the bus perform two functions:
Absorb the energy that would otherwise be ...
- 315k
5
votes
Accepted
Can I use GPS to synchronise two pieces of hardware?
Yes, GPS is used for exactly that purpose pretty often.
GPS receivers often emit a sharp pulse-per-second signal. Together with the current GPS or UTC time that you can query through the usual means (...
- 98.4k
4
votes
gps performance for synchronization
Simply because the system is more than good enough to do what's asked of it.
The power is low, but it's enough for a sensitive receiver with a clear view of the sky to reconstruct with high ...
- 7,977
4
votes
Are Newfoundland's and Quebec's power grid synchronized
No, the Quebec's grid is isolated from the rest of the North American continent. This is due to the historical decision to make sure that Quebec is 100% independent in terms of energy production. ...
- 1,126
4
votes
Accepted
Create a synchronous network of 400 devices
First, synchronize all of the devices to a common timebase using NTP, PTP or GPS, depending on your actual accuracy requirements (on the order of ms, µs, or ns, respectively).1 NTP should be ...
- 177k
Only top scored, non community-wiki answers of a minimum length are eligible