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t9x pcm compatiblity (resolution)

PostPosted: Sat Sep 15, 2012 12:23 am
by Wallcrasher
Hi! everyone, i recently purchased a brand new t9x mode 1 ver.2 transmitter and 2 matching receivers from hobbyking, so far no problems but i still have to set it up in a foamy for testing.
My question is if a want to have a fail safe feature i would have to upgrade to frsky module and matching rx. i need to know if the frsky module and receiver combo are pcm type of signal, in the description of the frsky module it says resolution 3072. but there's no mention if you have to use the t9x in pcm mode.

i just want to make sure before i do the upgrade thanks!
i would appreciate as much input as possible..

Here is the description
FrSky DJT 2.4Ghz Combo Pack for JR w/ Telemetry Module & V8FR-II RX
it says that it uses what is called " accst " type frequency switching . (any good or better than other systems??)

FrSky DJT is compatible with JR transmitters following:
JR: 347, 388, 783, U8, PCM10, PCM10S, PCM10SX, PCM10IIS, 8103, J9303, PX, 9XII, 11XZERO <<------- notice the 9xII ! t9x ver 2 ??

Receiver Specification:
Operating voltage: 3.0~16V(HV Version)
Power consumption: 30mA
Resolution: 3072
Latency: 22ms
Number of channels: 8
Range: 1.5km-2.5km
Dimensions: 44 x 24 x 14 mm
Weight: 9.3g

Module specification:
Operating voltage: 6.0V-13.0V (can handle 3S!)
Power consumption: 50mA
Output Power:: 60mW
Resolution: 3072 (11bit)
Dimensions: 63.9x48.5x36.5mm

Re: t9x pcm compatiblity (resolution)

PostPosted: Sat Sep 15, 2012 4:37 am
by quarry44
Frsky is a superior system,but a useful option is to change the transmitter firmware to ER9X.This gives much better programming options.I do believe failsafe is an option on the standard 9X,but since I never used mine in standard configuration,I could be wrong.
As far as pcm/ppm goes,the Frsky instructions specifically state to ensure the transmitter is in ppm mode before trying to bind the receiver.
Other than removing the aerial and it's wire,I didn't change anything on the transmitter before plugging in the Frsky module,and it worked fine straight off.
I hope that answers your question

Re: t9x pcm compatiblity (resolution)

PostPosted: Sat Sep 15, 2012 1:20 pm
by Wallcrasher
Well yes and no, what i really want to know is since the t9x can produce a pcm steam , what is the resolution of that stream of pulses, the reason why i am asking is are there any receivers out there that can work in pcm mode with the t9x if not then what purpose if any to have a feature that you can't use!!.

i think that unless i am wrong , the frsky upgrade uses the PPM stream from the t9x and converts it to some sort of stream with a resolution of 3072 bits.
i know that PCM mode has been around for quite a while and allows for failsafe feature to work.
The main reason for my post is that for me the frsky combo upgrade is an inexpensive alternative for have failsafe at such a price!
But i need more info on the upgrade such as resolution, what kind of data stream is used and why does it have more range than other systems

My next problem is witch of the 2 frsky upgrades do i choose?? one has no telemetry the other has telemetry but is more expensive.

Thanks for the reply.

Re: t9x pcm compatiblity (resolution)

PostPosted: Sat Sep 15, 2012 6:14 pm
by BillGriffiths100
Bruce has explained quite a bit about rc systems follow this you can also access it from the front page of RCreviews.