Turbo code encoder COM-7001
  -> Turbo code decoder COM-7001 
    -> BER measurement COM-1005.

Note: This test can only work with COM-7001 firmware revision 22 and above.
ComBlock Control Center rev 2.24 or above must be used.

Back to Back turbo code encoder/decoder with BER measurement.
The turbo-code encoder is placed in signal generator test mode 
whereby a periodic 2047-bit sequence (PRBS-11) is being transmitted. 
The resulting data stream is FEC encoded, FEC decoded. 
The end to end BER is measured using the COM-1005 module. 
The data rate between encoder and decoder is set by a numerically controlled
oscillator within the encoder module. 
Coded data rate: 11.718 Mbit/s.
FEC rate: 0.793
Turbo code selection: 2D (32,26)*(32,26)
Frame size: 1024 bits
6 decoding iterations.

Proper operation can be verified as follows:

(a) turn the COM-7001 -> COM-7001 -> COM-1005 assembly power on. 
Connect a serial cable between the COM-7001 encoder and a host computer.
Start the ComBlock Control Center. 
Import the 7001_7001_1005.stn settings file from the File | Import menu.
After successful import, recycle power.

(b) using an oscilloscope probe:

COM-1001 TP1 is high, indicating demodulator carrier lock 

COM-7001 decoder  TP4 shows the reconstructed periodic start of frame pulses 
every Turbo-code block (1024 bits + 32 bit unique word). 

COM-7001 decoder TP2 D_GOUT shows how much decoding capacity is used in the Turbo code 
decoder for this configuration (nearly 100% capacity, 6 decoding iterations). 

COM-7001 encoder TP1 E_GOUT shows how much decoding capacity is used in the Turbo code 
encoder for this configuration (approximately 46%). 

COM-1005 TP1 is high, indicating synchronization with the 2047-bit periodic test pattern 

COM-1005 TP3 is low, showing no bit error pulse.


(c) from the ComBlock control center check the BER (COM-1005 status).
It will show no bit errors (REG 1 through 4) and the synchronization bit (REG5 bit0) is high.