Baseband frequency or bandwidth depends on datarate, modulation and filters.
for example
The LT®5575 is an 800MHz to 2.7GHz direct conversion
quadrature demodulator optimized for high linearity
receiver applications. It is suitable for communications
receivers where an RF signal is directly converted into I
and Q baseband signals with bandwidth up to 490MHz.
Let say I desire to used a low cost envelope detector to detect the UHF signal, where the detector generally consists of a Schottky diode,and a shunt resistor and capacitor.
So in this case, how am I going to choose the proper value for the R and C?Anyone knows it?
The modulation or baseband bandwidth may be different according to the used standard. ISO/IEC 18000-6 (860-960 MHz) specifies bitrates of 10 to 40 kbps.
Basically, the usable bandwidth is constrained by ISM regulations, thus a considerably higher bandwidth is effectively impossible.
I think the RF bandwidth will be the same as baseband bandwidth bcos after baseband filtering there is no inband filter. only upconversion.
In standards the Transmit mask is specified , so precisely can we tell the BB bandwdth by measuring RF bandwidth???
for RFID 200Khz or 500KHz, as per local regulation.
Yes, sounds plausible. I expect, that a bandwidth shaping would be carried out at the baseband if not already achieved by the properties of the modulating signal.