Hi:
Please tell me, how much the TVRX receiver sensitivity?
Thanks in advance.
Mei-Wen Li (Emily)
National Cheng-Kung University Dept. of
Computer Science and Information Engineering
[email protected]
On 03/31/2010 03:59 AM, Li Mei-Wen wrote:
Hi:
Please tell me, how much the TVRX receiver sensitivity?
Thanks in advance.
The “sensitivity” of a receiver depends on a few factors, so it’s hard
to give a meaningful answer.
The tuner module (MT4937) has a noise figure of about 8-10dB, which will
be the dominant contributor
to sensitivity.
But the “sensitivity” depends heavily on what type of signal you’re
trying to detect/demodulate, etc.
In FM radio, for example, “sensitivity” is often quoted in terms of the
minimum signal level (usually
in microvolts) that is required to produce an audio output signal that
is of acceptable quality, or that
has a certain minimum SNR (Signal-to-Noise Ratio).
Some types of signals are more “noise robust” than others. Standard AM
signals, for example, are
notoriously non-robust, so they require less-noisy signals (more power
received at the input of the
receiver) to produce equivalently-acceptable audio output.
Narrowband digital modulation schemes with built-in
forward-error-correction are much more
noise tolerant, and so can operate acceptably well with smaller signals
available at the antenna
input.
You should be able to use the quoted noise figure of the MT4937 (used on
the TVRX) of 8-10dB to work
out the sensitivity levels for your application. If an 8-10dB noise
figure produces unacceptable results
in your application, then placing a low-noise-amplifier (less than 2dB
noise figure) ahead of the TVRX
will vastly improve your results.