Receiver & Transmitter module

[ydoubleuz@gmail.com]

Hi All,

There are 2 "SAW resonator" (I presume); 1 in the receiver module and
another in the transmitter - DIP, metal casing; similar to an
oscillator.

I went through the web trying to understand about this component,
however there are none stating a "receiving resonator" or
"transmitting resonator".

The query is raised as i saw the markings on these components
"R447.9375" on the receiver module and "T447.975" on the transmitting
module.

My assumption:
1. "R" & "T" denotes receive & transmit respectively.
2. The digits represent the frequencies.
3. If I replace these 2 "R" and "T" to same frequency value, they
should work.

Not sure if these assumptions are true or these components are not
resonators. Can anyone help please?

Btw the exact markings on the receiver is:
R447.9375
87.4475
SE-0401

Thanks in advance.
ywz

 

[asdf]

On Tue, 27 Sep 2011 01:36:21 -0700, ydoubleuz@gmail.com wrote:

My assumption:
1. "R" & "T" denotes receive & transmit respectively. 2. The digits
represent the frequencies. 3. If I replace these 2 "R" and "T" to same
frequency value, they should work.

They should work if the frequency is close enough so the signal can pass
any tuned circuit or filter in its path, should they exist.

Not sure if these assumptions are true or these components are not
resonators. Can anyone help please?

They should be SAW based as, IIRC, crystals cannot go that high in
frequency by themselves. Many resonators I've encountered are "crystal-
like" passive devices, ie. something that can be put in oscillation into
an active circuit or used as a filter depending on how you connect it,
but information is a bit scarce on the net. Some examples can be found
though by googling for saw+schematic+receiver(or transmitter).

If anybody has more information, I'm interested in the subject as well!

 

[ydoubleuz@gmail.com]

Don't seems to be much interests online...

The confusing part is the marking "R" & "T" ... if they are resonators
then they should not be differentiated between transmitter and
receiver.

Googling on "saw resonator" did not provide any insights the the
difference between the receiver and transmitted.

Am I missing something here?

Lets hope some gurus will provide some leads. =)

 

[Michael Black]

On Tue, 1 Nov 2011, ydoubleuz@gmail.com wrote:

Don't seems to be much interests online...

The confusing part is the marking "R" & "T" ... if they are resonators
then they should not be differentiated between transmitter and
receiver.

It would depend on what they are being used for.

For signal frequency filtering, there wouldn't be a different.

But SAWs are also used in oscillators, and a lot of recievers are
superheterodyne where the incoming signal is mixed a different frequency.
In that case, the transmit SAW would be at 500MHz (just as an example)
while the receiver SAW would be at 490MHz (so the signal is mixed down to
10MHz).

I don't know what the norm is for SAWs, but in the old days it was common
to stamp crystals with the signal frequency, rather than the fundamental
frequency it really oscillated on, or the frequency it injected into the
receiver to convert the signal frequency down to the intermediate
frequency. Sometimes they might be marked with "T" or "R" to indicate
their function, but you couldn't tell their actual frequency without
putting it in an oscillator to measure, or without knowing the equipment
it was intended for (which would then define where the transmit oscillator
oscillated at and how much that was multiplied, and then the IF frequency
of the receiver and again how many times the receive oscillator wsa
multiplied).

Michael