Cmostek Cmt2300aw Instruction Manual

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Overview

This document introduces the RF parameter configuration, OOK and FSK modulation parameter configuration

for CMT2300AW RFPDK.

The product models covered in this document are shown in the table below.

Table 1. Product Models Covered in This Document

Part No.

Frequency

Modem

Function

Configuration

Package

CMT2300AW

127 - 1020MHz

(G)FSK/OOK

Transceiver

QFN16

Before reading this document, it is recommended to read AN142-CMT2300AW Quick Start Guideline to learn the basic usage of

CMT2300AW.

AN149

CMT2300AW RF Parameter Configuration Guideline

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Table of Contents

1Tx and Rx Parameter Configuration............................................................................................... 3

1.1 Basic Parameter Configuration...........................................................................................................................3

1.2 OOK Demodulation Configuration......................................................................................................................4

1.3 FSK Demodulation Configuration.......................................................................................................................5

1.4 CDR Design Index and Mode Selection............................................................................................................. 6

1.5 Register Classification and Use in the Tx Bank................................................................................................ 10

2Revise History..................................................................................................................................11

3Contacts........................................................................................................................................... 12

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1 Tx and Rx Parameter Configuration

1.1 Basic Parameter Configuration

Figure 1. RF Parameter Configuration Interface

The registers corresponding to these parameters are stored in the frequency bank, the symbol rate bank,

and the Tx bank, It

needs to be calculated by complex calculation. The user does not need to understand the

calculation process and the specific

meaning of the register.

RFPDK interface parameters are easy to understand. The following configurations need attention.

How to set the Deviation:

Generally speaking, the following 3 points are recommended when configuring the Deviation:

1. 4kHz < Deviation < 200 kHz, and Symbol rate * 0.5 + Deviaiton<= 250 kHz

2. Symbol rate * 0.25 <= Deviation，that is, the modulation index must not be less than 0.5 (MSK).

3. In the case of meeting the above two conditions, if Symbol rate * 0.5 <= Deviation <= Symbol rate *

2, it can achieve the best

sensitivity.

How to set the crystal PPM

The user inputs the crystal tolerance values for Tx and Rx respectively in RFPDK. If inputting +/-20 ppm

respectively, it means that the worst case between the transmitter and receiver is the crystal frequency

difference of 40 ppm. The user should consider the worst case to set these two tolerance values, which affect

every bandwidth setting within the receiver.

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1.2 OOK Demodulation Configuration

Figure 2. OOK Configuration Parameter

Here is the configuration suggestion:

Table 2. OOK Parameter Configuration

RFPDKInput

Parameter

ConfigurationSuggestion

Bandwidth

It is recommended to selectAuto-Select

DemodMethod

Middle Demodulation response speed is fast. The advantage is that the

correct demodulation

can be made immediately after each

communication is started. The disadvantage is that if

there is a spike

mutation in the packet (a sudden abrupt increase in amplitude), it will

affect

the subsequent period of demodulation.

Average Demodulation response speed is slow. The disadvantage is that

it takes time for

each communication to demodulate correctly (usually

10-20symbols). The advantage is that

the demodulation effect will not be

affected if there is a spike mutation in the packet (a

sudden abrupt

increasein amplitude).

The experience is that the spike mutation only exists in some special

applications, so it is

generally recommended that the demodulation

method of Middle can speed up the

demodulation and reduce the

receivingtime.

Long-ZeroNumber

The user needs to input this value to tell the receiver how many

consecutive 0 there are at most in the packet. The receiver will modulate

the relevant parameters to ensure the best demodulation results.

CDRType

In the packet mode, the user needs to detect Preamble or Sync. The

symbol rate clock recovery function has to be turned on, and the later

chapter will describe

how to use CDR in detail.

CDRRange

How to input Parameters when CDR = Tracing. The later chapter will

describe how to use CDR in detail.

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1.3 FSK Demodulation Configuration

Figure 3. FSK Configuration Parameter

Here is the configuration suggestion.

Table 3. FSK Parameter Configuration

RFPDKInput

Parameter

ConfigurationSuggestion

Bandwidth

RecommendselectingtheAuto-Select.

AFC

AFC switch. It is usuallyrecommended to open.

AFC Method

AFC method. Recommend selecting theAuto-Select.

CDRType

In the packet mode, the user needs to detect Preamble or Sync. The

symbol rate clock recovery function has to be turned on, and the later

chapter will

describe how to use CDR in detail.

CDRRange

How to input parameters when CDR = Tracing. The later chapter will

describe how to use CDR in detail.

Data

Representation

Select the two frequencies of the (G)FSK, which represents 0 and which

represents 1. The default configuration is usually selected.

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1.4 CDR Design Index and Mode Selection

The corresponding RFPDK interface and parameters are presented:

Figure 4. CDR Configuration Parameter

Here is the configuration suggestion:

Table 4. CDR Parameter Configuration

CDRType

CDR_MODE<1:0>

CDR DR Range

CDR_RANGE_SEL<1:0>