HSP50215EVAL Ver la hoja de datos (PDF) - Intersil

Número de pieza

componentes Descripción

Lista de partido

HSP50215EVAL

DSP Modulator Evaluation Board

Intersil 

HSP50215EVAL

Adding the log of the noise bandwidth converts from C/N to

C/No. Subtracting the log of the symbol rate converts from

C/No to Es/No. The modulation factor converts from Es/No

to Eb/No using the equation:

MF = 10LOG[bits/symbol]

This yields MF = 0dB for BPSK, MF = 3.01dB for QPSK, and

MF = 4.77dB for 8 PSK.

An Example Eb/No Calculation

Data File:

QPSKPN, A = 1.0, FSAMP = 128ksym/sec

Noise File:

GN16K, std dev. = 0.25, FSAMP = 400ksamp/sec

Data filter:

IS136B, DC gain = 0.658, NBW = 1.004 x FSAMP

Noise filter:

RRC35A4xDC gain = 0.5, NBW = 0.989xFSAMP

Signal Atten:

20 dB, 26 / 256 = 0.1016

Noise Atten:

14.6 dB, 48 / 256 = 0.1875

Begin by calculating C/NdB:

C/NdB= 10LOG((1.0x0.658x0.1016)2/2(0.25x0.5x0.1875)2)

= 10LOG((4.4693x103)/(1.0986x103))

= 6.094dB

Continue by calculating Eb/No:

Eb/No= 6.094-3.01-10LOG(128,000)+10LOG(0.989x400000)

= 3.084 - 51.072 + 55.973

= 7.98dB

Note that the values for A, standard deviation, DC gains, and

noise bandwidths are found in the file headers of the

example filter and stimulus files provided. When main menu

item (7) is executed, four configuration files are generated,

for the various channels. These files list the hex values for all

of the control registers of the HSP50215. The channel (1, 2,

3, or 4) is indicated by the file suffix. The value of the

multiplier for the attenuators is found in Register 17. This

value, converted to decimal and divided by 256, yields the

linear attenuation multiplier value.

Note that there is an error introduced due to the 8-bit

quantization of the gain control value. The error is small for

attenuations close to 0dB but can be on the order of a tenth

of a dB for attenuations greater than 15dB and as much as

1dB at the bottom of the range.

Exercise #7: PRBS Data

This exercise will configure the board to bypass the filter and

not upconvert, so that the user PRBS data is output. This

configuration is useful for verifying stimulus files that are

short data sequences.

Go to the main menu. Select item (I) and set the following

parameters:

(9)48

(0)Returns to the main menu

This turns channel 1 off.

Select main menu, item (4) and set the following parameters:

(1)0

(7)Stimulus/bpskpn

(8)15

(9)3

(0)Returns to the main menu

This sets the channel 4 stimulus file to be a 15 bit PRBS.

The filter was already set to bypass. The IF is set to 0Hz.

Select main menu item (7) to compute the register values.

Select main menu item (8) to configure the board.

Select submenu item (5) to configure all 4 channels.

Select sumenu item (3) to load both the modulator and

pattern RAM.

When the submenu reappears, the download is complete.

The output waveform should be the input PRBS data

pattern. You should note that this configuration can be used

to verify the maximum input rate by changing the input

sample rate of channel 4 to be < fOSC/16. Varying the input

sample rate will illustrate that with too high of an input

sample rate, the filter does not have sufficient time to

complete an output calculation, and no PRBS pattern is

output. By lowering the input sample rate again, until the

PRBS pattern reappears, the maximum input sample rate

can be determined for your evaluation board/oscillator

combination. Note that a similar process can be used to

determine the maximum input rate of each of the example

filter files, taking care to enter the proper DS and IP values

for each filter as noted in Appendix G - Descriptive File List.

Generating User Configurations

Now that you understand the basics of controlling this

modulator evaluation board, you should be able to edit the

example configuration and stimulus files to obtain the test

figuration you desire. Remember that it is best to begin with

the files that most closely match the desired configuration.

Appendix G - Descriptive File List has a description of these

files.

11

Share Link: