Texas Instruments TMS3637P, Data Manual

Page: 31 / 53

5–13
Q-State Receiver
CG = 0, CH = 0
2 Codes
CD,CE 4 Codes
CD, CE 8 Codes
CD, CE 1 Code
CD, CE 2 Codes
CD, CE 4 Codes
CD, CE 8 Codes
CD, CE
Receiver
CA = 0, CC = 0
Normal
CB = 1
Modulated
CB = 0
CD CE
NO. OF
CODES
0
1
0
1 0
0
1
1 1
2
4
8
Analog
CF = 0 Logic
CF = 1
Train Receiver
CG = 1, CH = 1
VTR Receiver
CG = 1, CH = 0
Analog
CF = 0 Logic
CF = 1
Noninverting
Inverting
TRAIN CODES
Normal
CB = 1
Modulated
CB = 0
Normal
CB = 1
Modulated
CB = 0
Analog
CF = 0 Logic
CF = 1
Figure 5–7. Receiver Configurations
5.12.1 Normal Mode (CB = 1)
The normal receiver function corresponds to a normal transmitter.
5.12.2 Modulated Mode (CB = 0)
The modulated receiver functions in a way that corresponds to a modulated transmitter. The oscillator
frequency of the receiver must be 480 kHz. The signal used as an input must be demodulated to the carrier
frequency of 40 kHz and then sent to IN.
5.12.3 Analog Mode (CF = 0)
In this configuration, the received code is sent directly to IN where it is amplified and passed through a
comparator to filter and square the received code waveform to logic levels. The phase of the output signal
of the internal amplifier section is reversed with respect to the input. The capacitor connected between CEX
and GND and the internal resistor of 178
Ω
determines the cutoff frequency of the amplifier, which is in a
high-pass configuration.