ComBlock COM-1826 Manual - Page 9

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Modulated signal

16-bit amplitude scaling factor for the

amplitude

modulated signal.

The maximum level should be adjusted to

prevent saturation. Saturation can easily be

checked by visualizing the input signal

using ComScope.

REG29 = LSB

REG30 = MSB

Output center

Fixed frequency offset applied to the

frequency

)

output samples.

32-bit signed integer (2's complement

representation) expressed as

* 2

REG81 (LSB) – REG78 (MSB)

Spectrum

Invert Q bit

inversion

0 = off

1 = on

REG61(0)

BPSK / SQPN

0 = BPSK

1 = SQPN

REG61(1)

SQPN

0 = different data on I and Q channels

single/double

(including the case when bits of a single

source

input bit stream are sent alternatively to the

I/Q channels). Independent symbol rates on

I/Q channels. Uses two FEC encoders.

1 = identical data on I and Q channels.

Uses one FEC encoder

REG61(2)

Alternating I/Q

When enabled, the input data stream is

bits

demultiplexed into the I and Q paths. The

symbol rate must be identical on both I and

Q channels. Two independent FEC

encoders are used on the I and Q paths

respectively.

Enabled(1)/Disabled(0)

REG60(7)

½ symbol delay

A ½ symbol delay can be added to the Q

on the Q path

modulator path

Enabled(1)/Disabled(0)

REG60(6)

Data format

Data format conversion from the NRZ-L

converter

input to NRZ-L/M/S format prior to the

FEC encoder.

0 = NRZ-L to NRZ-L

1 = NRZ-L to NRZ-M

2 = NRZ-L to NRZ-S

REG61(5:3)

Convolutional

Disable (0) / Enable (1)

FEC encoding

REG61(6)

clk_p

Additive White

16-bit amplitude scaling factor for additive

Gaussian Noise

white Gaussian noise.

gain

Because of the potential for saturation,

please check for saturation when changing

this parameter. Saturation can easily be

checked by visualizing the input signal

using ComScope.

REG31 = LSB

REG32 = MSB

External

When using an external transceiver such as

transmitter gain

the COM-350x family, the transmitter gain

control

can be controlled through the

TX_GAIN_CNTRL1 analog output signal.

Range 0 – 3.3V.

REG59: LSB, REG60(3:0): MSb

TX_ENB

The TX_ENB signal at the interface

control

controls the RF transmit circuit.

0 = off

1 = on

REG60(4)

Network Interface

Parameters

Configuration

MAC addresses LSB

In order to ensure the uniqueness of

MAC addresses, users can define bits

7:1 through REG236(7:1).

The MAC addresses upper bits are

automatically tied to the nearly unique

FPGA DNA_ID. MAC address bit 0 is

either 0 (LAN1) or 1 (LAN2).

REG236(7:1).

IP1

multicast

address

4-byte IPv4 address used for SDDS

(LAN xB connector

input stream.

on backpanel)

Example : 0x E1 00 00 01 designates

address 225.0.0.1

Use 0.0.0.0 to signify that multicasting

is not supported.

REG33 (MSB) – REG36 (LSB)

IP1

static

address

4-byte IPv4 address used for SDDS

(LAN xB connector

input stream.

on backpanel)

Example : 0x AC 10 01 80 designates

address 172.16.1.128

The new address becomes effective

immediately (no need to reset the

ComBlock).

REG37 (MSB) - REG40 (LSB)

IP2 address (LAN xA

4-byte IPv4 address used for receiver

connector on

output, modulator inputs and

backpanel)

monitoring and control.

Example : 0x AC 10 01 80 designates

address 172.16.1.128

The new address becomes effective

immediately (no need to reset the

ComBlock).

REG41 (MSB) - REG44 (LSB)

Destination IP

4-byte IPv4 address

address

Destination IP address for UDP frames