Few more Questions on TMS3705

Whoops...sorry guys I should have been more attentive to the role of the "Mode Register" and the "State Diagram" on page 7 of SCBS881B.

I "think" I now understand that "0000" is the default for MCR bits 1,2,3,4 = divide by 119 = 134.2kHz
I "think" ...................................."0001" ........................................................................ 114 = 128.56kHz
I "think" ...................................."0010" ........................................................................ 115 = 129.69kHz
I "think" ...................................."1011" ........................................................................ 124 = 139.84kHz

I am prepared to forget these "uP manual controlled" frequency determinations for the moment and focus in on the "adapted automatically mode"

I "think"........................"1111".........................................MCR.............................................= Auto-Adapt.

and I "think" I understand that the distant transponder reply frequency is detected/determined in the 100 uS window which starts 1.6mS after the end of the TXCT...ie between 50+(1.6mS - 1.7mS).

I assume this is to allow the "transmitter resonance damping" to sufficienty diminish the "ringing" of the last charge energy....however...questions arise if the damping is wrong or insufficient ...but perhaps for later as it concerns tuning and critical damping?

Sorry all, I had a lapse...however am I right so far?

Regards

Ray

Sorry Guys, I'm struggling to do it alone...I have to ask for help.

Can someone in simple words tell me what bit6 in the MCR does ... ie 00000010 into MCR

Name=RX_AFC...Description...[0=Demodulator threshold adapted automatically]...[1=Demodulator threshold is defined by DATA_BIT(4:1)]

Doubtless I am covering old ground so perhaps some one could simple point me to some reference discussion on this matter.

I think SCBS881B  pp5 "DIGITAL DEMODULATOR" is trying to speak to me about this, but I just failing to understand... (I'll keep re-reading it)...more help needed.

Regards

Ray

Question1, is there a remote possibility this new MRD2 will now use the TMS3705?
A1: The MDR2 is not using the 3705

Question2, I see in the "LF Technical Training Publication" on page 3 is a picture of a PCB labled "A Transceiver Module With antenna"....who makes this TMS3705A PCB module?...where can I buy one?
Q2: The PCB using the 3705 and a circular antenna is a part of teh demo tool RI-ACC-ADR1 but this became obsolete.

Question3, concerns the "self Adapting or fixed frequency charge-up" ...I still not sure how it works yet, but
my question is why is it there at all?
A 3: The 3705 is mainly used in low Q system and the TX frequency adaptation will not improve significantly the reading range.
        2nd the today transponder are more stable from the resonance point of view.  

If a tag is successfully read and validated why would you come back and bother optimizing (by adapting) the Power field frequency the second time round?...now you just read it better yes/no...one is surely enough?

Perhaps this frequency adapting process works on a partial read? in which case on the next pulse it is emitting a "better-matched" frequency...now it has a "better chance" of putting more charge into the "off-tune-tag"...yes/no?

Question4, what happens if two tags are in the detection volume...which take control? ...is this leading to a presumption this "mode" is to be used for tags passing in single file?
A4: The stronger one will dominate. About 6dB higher return field strength .

Question5: how/when does the chip know when to return to "un-adapt" back to it's quiescent 134.2khz frequency?
A5: what do you mean?

Hi!

I have a doubt!

How can I know that a TAG is detected by TMS3705? Is there any certain page available , which tells me that a tag is detected?

Reagards

Deepak!