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Frequency separation
The frequency separation, ∆f, is the difference between the frequency transmitted for a ‘0’ (f0)
and a ‘1’ (f1). That is, f0 = fC - ∆f/2 and f1 = fC + ∆f/2 where fC is the carrier frequency entered
in the ‘RF frequency’ field.
The frequency separation can be adjusted between 1 and 200 kHz in 1 kHz steps. The
default value is 20 kHz.
Depending on the chosen IF stage the recommended frequency separation is
5 - 40 kHz for IF = 60 kHz,
10 - 100 kHz for IF = 200 kHz.
5 – 20 kHz for IF = 455 kHz with external filter
The sensitivity depends slightly on frequency separation.
Data rate
The data rate can be set between 0.3 and 9.6 kbitps. The default setting is 1.2 kbitps. The
data signal transmitted to the DIO pin must be Manchester encoded. The noise bandwidth of
the receiver will be optimised to the selected data rate. Note that the baud rate is twice the bit
rate when using Manchester coding.
Power amplifier class
You can chose between four possible choices of PA-class: ‘Class A’, ‘Class AB’, ‘Class B’
and ‘Class C’. The default choice is ‘Class C’. The different classes are selected from a pulldown menu.
The selection of power amplifier operation class is a trade-off between output power,
efficiency and harmonic generation. In class A or AB the amplifier is working more linear, and
the harmonics will be low. However, the efficiency and the output power will also be low. For
increased output power and efficiency, class B or C should be used, with the cost of
somewhat higher harmonics.