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Block Diagram (FSK/MSK/GFSK Digital Demodulator) 

Bias 
Removal

Real or
Complex 
Input 
Samples

Sample
CLK

Bit Timing
Loop

ADC
Sampling
Rate NCO

Symbol 
Decoding

Demodulated
Data Bits

Magnitude

Half-Band
LPF x2

Burst
AGC

Rx Gain
Control

Variable
Decimation
CIC Filter

Frame/
Superframe
Detection

ADC
sampling
clock

error

8*N samples
per symbol (typ.)

1 sample
per symbol

Start of 
Frame/
Superframe

 

 
 

Block Diagram (FSK/MSK/GFSK Digital Modulator) 

1/2

n

Elastic 
buffer
1/2/4/8*
16Kbit

Symbol 
rate

Sample CLK

8-bit parallel 
data

PRBS-11
test 
sequence

Frame
formatting
(sync word,
preamble)

Flow control

Frequency 
reference

PLL

processing clock

symbol clock

M-ary
mapping
(2,4,8)

modulation
order (2-FSK,
4-FSK, etc)

Gaussian
Filter
BT = 0.3
or 0.5

bypass

X

modulation
index h

+

Output
center
frequency

NCO

X

X

Gain

I

Q

 

 

 

Electrical Interface 

 

Other 
Digital 
Modem 
Interfaces 

Definition 

USB 2.0 

Type B receptacle.  This interface 
supports two virtual channels: one for 
monitoring and control, the other to 
convey information data between the 

modem and a host computer. 

LAN / TCP-
IP 

Networking requires an additional 
10/100/1000 Mbps Ethernet adapter 
(COM-5102 or COM-5401) plugged in 
the left (J6) connector. The COM-1503 
includes a TCP-IP server, awaiting a 
remote client connection at port 1024. 

 

Power 
Interface 

4.75 – 5.5VDC. Terminal block. Power 
consumption is approximately proportional 
to the symbol clock rate (f

symbol_clk

). The 

Содержание COM-1503

Страница 1: ...ame Demodulator inputs Digital 12 bit real or complex up to 120Msamples s Sampling clock is controlled by this board Modulator outputs Digital 1 bit or 16 bit up to 240 Msamples s Modem data I Os o Two synchronous serial interfaces o USB 2 0 o LAN TCP with optional COM 5401 COM 5102 Extensive test monitoring o BER measurement when transmitting PRBS 11 test sequence or frame sync o PRBS 11 test seq...

Страница 2: ...external ADCs BER Measurement ADC sampling clock Demodulator connectivity Burst Modulator USB 2 0 high speed TCP IP RJ 45 10 100 1000Mbps COM 5102 5401 Synchronous Serial interface 98 pin PCIe connector Multiple Inputs input selection output selection Digital output samples various formats pinouts to external DACs or DDS Internal Test Sequence Generator 14 bit precision I Q mux d external DDS 2 I ...

Страница 3: ... 2 Full Duplex modem Modem Receiver COM 30xx COM 1503 D A converter COM 2001 Tx Rx data stream via USB RF or baseband modulated input RF modulated output RF modulator COM 400x Use example 3 70 MHz IF Burst Modulator USB 70 MHz DDS Modulator COM 1503 COM 4004 Use example 4 Demodulator only Receiver COM 30xx RF or baseband modulated input Demodulator COM 1503 FEC decoder COM 7002 COM 1009 etc rx dat...

Страница 4: ...cy reference PLL processing clock symbol clock M ary mapping 2 4 8 modulation order 2 FSK 4 FSK etc Gaussian Filter BT 0 3 or 0 5 bypass X modulation index h Output center frequency NCO X X Gain I Q Electrical Interface Other Digital Modem Interfaces Definition USB 2 0 Type B receptacle This interface supports two virtual channels one for monitoring and control the other to convey information data...

Страница 5: ...uration An entire ComBlock assembly comprising several ComBlock modules can be monitored and controlled centrally over a single connection with a host computer Connection types include built in types USB Asynchronous serial LVTTL or connections via adjacent ComBlocks USB TCP IP LAN Asynchronous serial DB9 LVTTL PC Card CardBus PCMCIA The module configuration is stored in non volatile memory ...

Страница 6: ... Control Center software supplied with the module on CD In the ComBlock Control Center window detect the ComBlock module s by clicking the Detect button next click to highlight the COM 1503 module to be configured next click the Settings button to display the Settings window shown below ...

Страница 7: ...frequency reference REG2 7 Symbol rate fsymbol rate tx The modulator symbol rate is in the form fsymbol rate tx fclk_tx 2n where n ranges from 0 1 sample per symbol to 15 symbol rate fclk_tx 32768 n is defined in REG3 3 0 Modulation Index h Modulation index h Format 3 8 Thus 0x0080 represents an index of 0 5 MSK Valid range 0 7 996 REG4 7 0 LSB after decimal point REG6 7 5 MSB before decimal point...

Страница 8: ...EG15 LSB REG16 REG17 MSB Preamble extension Prepend a dummy preamble to the packet to give the receiver AGC time to converge before the sync field Expressed as number of symbols 8 Valid range 0 255 representing 0 to 2040 symbol preamble Adjust as a function of the receiver AGC response time REG18 Output selection The output selection is based on the firmware option i e personality loaded in the FP...

Страница 9: ...rsion occurs in most COM 300x receiver modules 0 off 1 on REG11 5 Nominal Center frequency fc_rx Expected center frequency of the received signal 32 bit signed integer 2 s complement representation expressed as fc_rx 232 fclk_rx Maximum recommended range 10 MHz REG53 LSB REG54 REG55 REG56 MSB BCH decoder bypass 0 BCH decoder enabled 1 BCH decoder bypassed REG32 4 Receive packet size Nplrx Receive ...

Страница 10: ...t left J6 connector 3 1 bit serial raw demodulator output right J9 connector 4 exclusively to internal BER measurement REG40 2 0 IP address 4 byte IP address 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 REG42 REG43 REG44 LSB Reserved REG45 through 50 are reserved for the LAN MAC address These registers ...

Страница 11: ... 0 port 1024 data stream SREG33 1 port 1028 monitoring control Ethernet PHY ID LSB Self check 22 when connected to COM 5102 or COM 5402 LAN interface SREG34 MAC address Unique 48 bit hardware address 802 3 In the form SREG35 SREG36 SREG37 SREG40 ComScope Monitoring Key internal signals can be captured in real time and displayed on a host computer using the ComScope feature of the ComBlock Control ...

Страница 12: ...he first equation describes a phase modulator with the modulated centered around the center frequency fc 2 cos 2 0 θ θ π t t f T E t s c s where Es is the energy per symbol T is the symbol period fc is the center frequency t θ is the phase modulation The COM 1503 implements a continuous phase FSK modulator There are no phase discontinuities between symbols The CPFSK phase modulation can be describ...

Страница 13: ...ween symbol alphabet and modulation symbol i a is described in the table below Symbol alphabet Modulation symbol i a 2 FSK 0 1 2 FSK 1 1 4 FSK 00 3 4 FSK 01 1 4 FSK 10 1 4 FSK 11 3 8 FSK 000 7 8 FSK 001 5 8 FSK 010 3 8 FSK 011 1 8 FSK 100 1 8 FSK 101 3 8 FSK 110 5 8 FSK 111 7 Gaussian Filter A filter with Gaussian impulse response can be used as pre filtering of the symbols prior to the continuous...

Страница 14: ...is used only on the first frame in a superframe A 32 bit synchronization field 0x5A0FBE66 In this field the bit length is set at 1 5 times the nominal symbol length to facilitate symbol synchronization at the receiver A 11 bit Barker code 11100010010 The preamble is always 2 ary modulated An inverted preamble marks the start of superframe SuperFrame Tx window start Tx window end Payload data Pream...

Страница 15: ... start 0 superframe period Master tx Remove unit rx detected start of superframe detected start of superframe Remove unit tx Master rx tx window start tx window end tx window start tx window end superframe period tx window end rx window start rx window end rx window start rx window end The remote unit superframe period starts immediately after detecting the inverted preamble It is therefore slight...

Страница 16: ...op can be closed or open with the gain frozen at a user specified level by software command Adjust gain AGC A D 12 bit DAC pin J4 B13 Subsample loop response time Detect near saturation COM 1503 AGC1 principle The user is responsible for selecting a preamble extension length see control register REG18 long enough to give the receiver AGC enough time to converge at the beginning of a packet Selecti...

Страница 17: ...e used once the correct network setting is configured and after a power cycle TCP IP As a Server the module opens the following sockets in listening mode Port 1024 modem data streams Port 1028 monitoring and control port Ping The module responds to ping requests with size up to 470 bytes Ping can be used to check the module response over the network Ping can be used at any time concurrently with o...

Страница 18: ...0 0 000 corner 3 000 3 000 2 840 0 160 Mounting hole Mounting hole USB DEV port MiniAB 5VDC Power Terminal Block 90 deg 2 840 2 840 Mounting hole 0 160 2 840 Mounting hole 0 160 0 160 Mounting hole diameter 0 125 Maximum height 0 500 Left connector 98 pin Straddle Mount Connector P N Sullins NWE49DHRN T941 J7 EXT REF Input external 10MHz SMA female Edge Mount J3 GND 5VDC SMA center pin 0 510 0 180...

Страница 19: ... 9 DATA_I_IN 7 DATA_I_IN 5 DATA_I_IN 4 DATA_I_IN 2 DATA_Q_IN 10 DATA_Q_IN 8 DATA_Q_IN 6 DATA_Q_IN 5 5 10 15 20 25 30 35 40 45 DATA_Q_IN 3 AGC1_OUT DATA_I_IN 0 DATA_Q_IN 1 DEMOD_TP 1 DEMOD_TP 2 DEMOD_TP 3 This interface is compatible with the COM 30xx family of RF receivers A1 B1 A49 B49 Top Bottom RX_CLK1 RX_DV1 RXD1 0 RXD1 1 RXD1 2 RXD1 3 GTX_CLK1 TX_EN1 TXD1 0 TXD1 1 TXD1 2 TXD1 3 CLK125_NDO1 IN...

Страница 20: ...5 DAC1_DIN_4 DAC1_DIN_3 DAC1_DIN_2 DAC1_DIN_1 DAC1_DIN_0 DAC_CLKIN_P DAC_CLKIN_N DAC2_DIN_15 DAC2_DIN_14 DAC2_DIN_13 DAC2_DIN_12 DAC2_DIN_11 DAC2_DIN_10 DAC2_DIN_9 DAC2_DIN_8 DAC2_DIN_7 DAC2_DIN_6 DAC2_DIN_5 DAC2_DIN_4 DAC2_DIN_3 DAC2_DIN_2 DAC2_DIN_1 DAC2_DIN_0 AUX_SPI4 AUX_SPI5 5 10 15 20 25 30 35 40 45 special use pins see schematics This interface is compatible with the COM 3504 dual Analog Di...

Страница 21: ...development platforms Configuration Management This specification document is consistent with the following software versions COM 1503 FPGA firmware Version 0 and above ComBlock Control Center graphical user interface Revision 3 05d and above The option and version of the FPGA configuration currently active can be read from the ComBlock Control Center in the configuration panel advanced Troublesho...

Страница 22: ...22 ComBlock Ordering Information COM 1503 FSK MSK GFSK Burst modem MSS 18221 A Flower Hill Way Gaithersburg Maryland 20879 U S A Telephone 240 631 1111 Facsimile 240 631 1676 E mail sales comblock com ...

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