why does a gyro need to know about receiver type?

[mayday1]

why does the HG-5000/LT-2100 need to know the receiver type? Even
if it needs to know the receiver type, how does it find out just from seeing
the pulses from channels 4 and 5?

I've had used a LT-2100 for a couple of years on a trex that have gone through several
types of 72MHz receivers as well as a couple spektrum receivers. I've
never did the receiver type setting but never noticed any differences when
switching receivers.

thanks

[widower]

I believe it can find out by the frame rate of the pulses. So one manufacture will send out the pulse for say channel 4 at a faster rate than another manufacture. The gyro's algorithm probably prefers to know when to expect the next pulse for the channel in order to predict how much it will need to correct for.

[Pinecone]

Nope, Rxes send out the pulses as it gets them for the Tx.

Now, some Rxes do have a different 0 to 1 signal voltage, and the gyro would need to know that in some cases.

[halley]

The Align GP750 has a setting for "normal" 1520uS or "fast" 760uS pulse timing. That's the time width of a "middle" position pulse. Most TX/RX will follow the normal, but I think we'll be seeing more and more of the faster pulse widths and less gap between pulses. The Futaba GY601 and GY611 gyros, S9256 and BLS251 servos are some examples of tail systems that expect the new fast pulse standard. I expect radios will follow suit and the whole system will be running faster.

[Pinecone]

That is for the SERVO, not the Rx.

The servo uses either a 1500us or 760us or a couple of other choices for what is center. Same with pulse rate, the gyro can do 50 Hertz or up to 330 Hertz with some servos.

The Rx still works at around 50 Hertz update rate, as that is what the Tx sends.

[widower]

Originally Posted by Pinecone

Nope, Rxes send out the pulses as it gets them for the Tx.

That's not exactly true with today's 2.4G rxs. Otherwise, we would not have available features such as servo sync.

The logitech gyro is trying to detect the true center for the rudder channel which can be different depending on what radio gear you are using. For example, Futaba outputs a 1.52ms pulse for center where JR outputs a 1.50ms pulse.

I expect that if you look at the frame rate and dead band between channel pulses of different radio systems, you could probably determine the manufacture (unless it's an old radio system that often used a device by Signetics).

[Pinecone]

OK, not EXACTLY when it gets them, but no faster than the Tx sends them.

And with the DX7 SE, some channels are only sent every other frame.

But you are still limited to a maximum of the Tx frame rate, which for most Txes is 50 Hertz.