If Section And Fmcw Ramp Settings; Table 4 If Vs. Fmcw Ramp Parameters Vs. Target Distance - Infineon BGT24LTR11 Manual

Distance2GoL (Software-Controlled FMCW) low-power radar shield using
BGT24LTR11 for range detection and human tracking
Hardware description: BGT24LTR11 Shield
IF stage
Stage 1 + Stage 2
(high gain)
4.8.1

IF section and FMCW ramp settings

The bandpass characteristics of the IF section are also determined from the FMCW ramp parameter settings.
Different ramp settings result in different IFs for targets at different distances. The baseband section is
designed to meet the required IF cut-offs. Table 4 gives an example of IFs produced by stationary targets at
particular distances corresponding to different sawtooth-type ramp parameters. These IFs are also called "beat
frequencies". The beat frequencies calculated in the table do not include the Doppler shift.
The �������� ������������������ ( ���� ) is calculated from the following formula:
Where R = target distance in meters (m)
∆f = ramp bandwidth in Hertz (Hz)
= ramp time in seconds (s)
��
��
c = speed of light in meters/second (m/s)
Table 4 IF vs. FMCW ramp parameters vs. target distance
Ramp
Ramp duration
bandwidth
(T ) (µs)
r
(Δf) (MHz)
1000 180
1000 200
1500 180
1500 (default) 200
2000 180
2000 220
Application Note
Designator Gain
U5A + U4A 57 dB
�������� ������������������ ( ���� ) =
Target at 50 cm (R)
0.60
0.67
0.40
0.44
0.30
0.33
Configurable components –
I section
All components as
mentioned for Stage 1 +
R49, R50, R32, C23, C24
2 ∗ R ∗ ∆f
c ∗ ��
��
Beat frequency (Fb) (kHz)
Target at 10 m (R)
12.00
13.33
8.00
9.00
6.00
6.70
page 20 of 32
Configurable components
– Q section
All components as
mentioned for Stage 1 +
R55, R56, C34, R63, C33
Target at 30 m (R)
36.00
40.00
24.00
26.70
18.00
20.00
2021-03-31
V1.0