ENGN4521/6521. Embedded Wireless. An LIPD Band RF Front End for DATV

Transcription

1 ENGN4521/6521 Embedded Wireless An LIPD Band RF Front End for DATV V3.0 Copyright G.G. Borg College of Engineering and Computer Science. Australian National University 1

2 Contents 1 Foreword 3 2 Assessment 3 3 Introduction 3 4 Description 3 5 Exercises 5 2

3 1 Foreword The ENGN4521 term project introduces digital amateur television (DATV). Amateur radio gives radio hobbyists a way to experiment with radio wave communications 1. We will build a DATV radio to transmit video to an existing software defined receiver using the satellite digital video broadcast standard (dvb-s) 2. 2 Assessment The project is worth 40% of the course mark and will be covered entirely in labs. The broadaimistoimplement aworking wireless video linkwiththehelpofanrtl-sdrsoftware radio receiver (sdr) - based DTV receiver 3. There are two separate projects. This document describes the RF front end. It is worth 20% of the course total mark. The appendix also contains an introduction to LINUX which will be using in the rest of the course. One of the exercises in this project includes an exercise in C programming. 3 Introduction This project is an rf electronics exercise involving the construction of (a) an rf up/downconverter to cross-band translate the MHz lipd (Low Interference Potential Device) band to an intermediate frequency (if) and (b) an rf power amplifier based on a common emitter amplifier using a BF199 VHF transistor. Note that because the LIPD band only permits 10mW (20dBm) EIRP (Equivalent Isotropic Radiated Power), the amplfier is really a low power common-emitter BJT amplifier. The information contained in this description and the solutions to a few short exercises provide the basis for a 5-10 page report. There is more to DATV communications system than is in the scope of the project. Students only need to concentrate on the assessment areas and their specific requirements. The report submission deadline is the end of semester. Emphasis should be placed mostly on providing worked solutions to the questions and demonstrating that you understand the principle of operation of the radio and the design choices. 4 Description A block diagram of the radio is shown in Fig https : //en.wikipedia.org/wiki/amateur r adio

4 MIXER LO IF RF QPSK IF LOW PASS 74MHz IF RF BAND PASS 24MHz LO 50MHz QPSK IF 55MHz BAND PASS 55MHz QPSK IF 55MHz Figure 1: Circuit schematic of the up converter. The inset shows the architecture of the double balanced ring diode mixer. There are two possible rf-ucs the main figure shows the 24MHz system which requires a mixer to convert from 74MHz to 24MHz and the lower figure shows 55MHz version which does not need a mixer. 4

5 Vdd (12V) R1 Lchoke = 10uH R2 BF199 50R 1 2 b c Rbias e 50R 3 Figure 2: Circuit schematic of the rfpa. 5 Exercises 1. Design, build and test an rfpa based on the BF199 VHF transistor for 12V power supply and 20-80MHz and 20dB gain. Your report should contain sections describing, Use of solve to model the amplifier. Be careful to design the amplifier for an input and output impedance of 50Ω. The construction process. Using components supplied in the lab build the amplifier on on a double sided FR4 PCB. Be sure to leave enough room for matching and input/output BNC connectors. Test results. Measurements of gain (transfer function). (8 marks) 5

6 2. Design, build and test a 74MHz low pass filter for an impedance of 50Ω. Be sure to include all design steps, performance predictions and test results in your report. (3 marks) 3. Design,buildandtesta24MHzbandpassfilterofbandwidth2MHzandanimpedance of 50Ω. Be sure to include all design steps, performance predictions and test results in your report. (3 marks) 4. Make anrfup/down-converter by laying outthe filtersonapcb withaminicir- CUITS ADEX-10 mixer (see appendix B) and a 5V-50MHz clock / local oscillator. Make measurements of the filter response (transfer function) and input impedance. Connect in the power amplifier and remake the measurements. (3 marks) 5. Read appendix A on linux, implement the udp talker / listener and demonstrate communications on a localhost. (3 marks) 6

7 APPENDIX A: LINUX When you connect to the LINUX O.S. using PUTTY (secure shell), you are presented with a terminal interface. This is an old-fashioned but very effective way to interact with a computer. In this section we describe the structure of LINUX file system and how you can use LINUX. First off type ls /. You should see the following. debian@beaglebone:~$ ls / bin dev home lost+found mnt proc run selinux sys usr boot etc lib media opt root sbin srv tmp var / refers to the root file system. This is the top folder or directory. There are a number of subfolders as follows: bin Contains many of the binary files that constitute the commands in the O.S. boot Contains kernel images and configutation files. The kernel refers to the LINUX operating system itself. dev Contains system interfaces (files) to the LINUX character and block devices (but not the network devices). Take a look at them by typing ls/dev. These devices can be opened as files by programs and allow the program to access LINUX device drivers. Can you think of what any of the devices refer to? etc Is where most of the system configuration scripts are located. home Is the home folder where the files are located of users who can access the system. There is only one user on my BBB system with uid debian. When you log in you arrive directly at your home folder. Here this is /home/debian. lib These are where the binary libraries are located. On WINDOWS think dlls. media This is where external storage devices can be mounted. Such devices include CD- ROMS, flash and external hard drives. Note tha term mount. The mount command is used to connect a folder (usually but not necessarily located in /media) to a block device in /dev. This allows the block device to be accessed as a folder. This may seem strange for MAC and WINDOWS users where mounting is performed transparently by the O.S. mnt serves a similar purpose to media proc Is actually a file system that is not located on the hard drive - or any block device. proc is located in RAM and is a volatile folder containing all of the system information. For example try cat /proc/cpuinf o to see what is contained in this file. 7

8 sbin is the superuser binary director. This is where the administrator-only commands are stored. usr is the usual place where new commands and other system files get stored when a user installs new software on LINUX. The following is a short list of basic unix commands that can be executed in the xterm. These commands are big programs usually with many options and can be very powerful. If you wish to learn more about a command type, man COMMAND NAME >. The man refers to the manual or man page for the command. man produces a scrollable interface inside the xterm. To navigate, simply use thearrow keys. To quit type < quit >. ls l list the files in the current directory in detailed format. cat FILE NAME.txt dumps the contents of a text file to the terminal. grep STRING FILE NAME.txt. ListalloccurrencesofSTRINGinfileFILE NAME. Note that wildcards are possible: grep STRING.txt. cp FILE NAME TARGET. Copy file FILE NAME to TARGET where TARGET could be another file or a directory. In this case the file FILE NAME is left in tact. mv FILE NAME TARGET. MovethefileFILE NAME totarget where TARGET could be another file or a directory. In this case the file FILE NAME is removed. rm FILE NAME. Delete the file FILE NAME. Be careful of this command. The rm command does not transport files to a safe haven such as the trash can. Instead it wipes them completely from the disk. mkdir DIR NAME. Create a directory DIR NAME. rmdir DIR NAME. Delete the directory DIR NAME. Only works if DIR NAME is empty. cd DIR NAME change to folder DIR NAME. format. The command cd takes you to your home folder. df. List total disk usage. Superfast way of finding out how much of your hard drive space is left. mount is used to mount file systems e.g. mount /dev/sdb1 /media/disk 8

9 ssh allows you to make a connection to another LINUX computer. Example 1: connect to user debian on a machine at IP address : ssh debian@ Example 2: Do the same but also allow an x-session: ssh X debian@ Example 3: Copy a file FILE NAME located in folder DIR1 NAME on the local machine to folder DIR2 NAME on debian@ scp DIR1 NAME/F ILE NAME debian@ : /DIR2 NAME/F ILE NAME note that DIR2 NAME has to be an absolute path. DIR1 NAME can be an absolute path but may be a relative path e.g../ is the current folder. nano is a simple screen text-editor with a built-in description of its ten only commands. The figure below shows how to use nano to create a simple c-program that prints Hello World! to the terminal. gcc o myfile myfile.c: compile C-program myfile.c into executable myfile. To run myfile, cd to the folder where it is located and type./myfile. If you are running X-windows the following are useful commands. /usr/bin/sof f icew orddoc.docx to open a WORD document /usr/bin/evincepdffile.pdf open a PDF /sbin/if conf ig: display the status of network devices. An example is shown below. Note that there are three network interfaces: eth0 the main ethernet interface, lo the loopback interface and usb0 the USB network interface (providing ethernet connectivity). debian@beaglebone:~$ /sbin/ifconfig eth0 Link encap:ethernet HWaddr 90:59:af:5b:cd:c3 inet addr: Bcast: Mask: UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:40 lo Link encap:local Loopback inet addr: Mask: inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:68 errors:0 dropped:0 overruns:0 frame:0 TX packets:68 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 9

10 RX bytes:6434 (6.2 KiB) TX bytes:6434 (6.2 KiB) usb0 Link encap:ethernet HWaddr c6:fe:62:d7:9a:82 inet addr: Bcast: Mask: inet6 addr: fe80::c4fe:62ff:fed7:9a82/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:630 errors:0 dropped:0 overruns:0 frame:0 TX packets:448 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:51153 (49.9 KiB) TX bytes:96967 (94.6 KiB) Finally there is /usr/bin/sudo. This command can be used to execute superuser commands by a regular user - provider the uid is stored in /etc/sudoers. You even need /usr/bin/sudo just to look at the file /etc/sudoers. A useful command requiring /usr/bin/sudo is /usr/bin/sudo halt which shuts down LINUX. Notice that these comands have been invoked from the folders where they are located. It is unnecessary to do this if these folders are in the PATH. PATH is an environment variable that can be found using the command echo $PATH. 10

11 Figure 3: Screenshot of nano in action UDP code /* ** talker.c -- a datagram "client" demo */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> 11

12 #define SERVERPORT "9999" // the port users will be connecting to int main(int argc, char *argv[]) { int sockfd; struct addrinfo hints, *servinfo, *p; int rv; int numbytes; if (argc!= 3) { fprintf(stderr,"usage: talker hostname message\n"); exit(1); memset(&hints, 0, sizeof hints); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; if ((rv = getaddrinfo(argv[1], SERVERPORT, &hints, &servinfo))!= 0) { fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv)); return 1; // loop through all the results and make a socket for(p = servinfo; p!= NULL; p = p->ai_next) { if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) { perror("talker: socket"); continue; break; if (p == NULL) { fprintf(stderr, "talker: failed to bind socket\n"); return 2; if ((numbytes = sendto(sockfd, argv[2], strlen(argv[2]), 0, p->ai_addr, p->ai_addrlen)) == -1) { perror("talker: sendto"); 12

13 exit(1); freeaddrinfo(servinfo); printf("talker: sent %d bytes to %s\n", numbytes, argv[1]); close(sockfd); return 0; /* ** listener.c -- a datagram sockets "server" demo */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #define MYPORT "9999" // the port users will be connecting to #define MAXBUFLEN 100 // get sockaddr, IPv4 or IPv6: void *get_in_addr(struct sockaddr *sa) { if (sa->sa_family == AF_INET) { return &(((struct sockaddr_in*)sa)->sin_addr); return &(((struct sockaddr_in6*)sa)->sin6_addr); int main(void) { int sockfd; 13

14 struct addrinfo hints, *servinfo, *p; int rv; int numbytes; struct sockaddr_storage their_addr; char buf[maxbuflen]; socklen_t addr_len; char s[inet6_addrstrlen]; memset(&hints, 0, sizeof hints); hints.ai_family = AF_UNSPEC; // set to AF_INET to force IPv4 hints.ai_socktype = SOCK_DGRAM; hints.ai_flags = AI_PASSIVE; // use my IP if ((rv = getaddrinfo(null, MYPORT, &hints, &servinfo))!= 0) { fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv)); return 1; // loop through all the results and bind to the first we can for(p = servinfo; p!= NULL; p = p->ai_next) { if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) { perror("listener: socket"); continue; if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) { close(sockfd); perror("listener: bind"); continue; break; if (p == NULL) { fprintf(stderr, "listener: failed to bind socket\n"); return 2; freeaddrinfo(servinfo); printf("listener: waiting to recvfrom...\n"); 14

15 addr_len = sizeof their_addr; if ((numbytes = recvfrom(sockfd, buf, MAXBUFLEN-1, 0, (struct sockaddr *)&their_addr, &addr_len)) == -1) { perror("recvfrom"); exit(1); printf("listener: got packet from %s\n", inet_ntop(their_addr.ss_family, get_in_addr((struct sockaddr *)&their_addr), s, sizeof s)); printf("listener: packet is %d bytes long\n", numbytes); buf[numbytes] = \0 ; printf("listener: packet contains \"%s\"\n", buf); close(sockfd); return 0; /* ** rtl_decode.c -- decodes rtl-sdr binary IQ to HEX */ #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> main(int argc, char **argv) { char infilename[200]; char outfilename[200]; char *name; FILE *infile; FILE *outfile; unsigned char Ichar, Qchar; int flag; int sample_counts; int Nbytes; 15

16 printf("usage:./rtl_decode infile outfile Nbytes\n"); printf("default filename=file.in Nbytes = 200\n"); if( argc < 4 ) { strcpy(infilename,"file.in"); strcpy(outfilename,"file.out"); Nbytes = 200; else { strcpy(infilename,argv[1]); printf("infile = %s\n",infilename); strcpy(outfilename,argv[2]); printf("outfile = %s\n",outfilename); Nbytes=(int)atoi(argv[3]); printf("%d\n",nbytes); infile = fopen(infilename,"r"); if( infile == NULL) { printf("could not open file\n"); exit(exit_failure); outfile = fopen(outfilename,"w"); if( outfile == NULL) { printf("could not open file\n"); exit(exit_failure); flag = fscanf( infile, "%c", &Ichar); flag = fscanf( infile, "%c", &Qchar); // while( EOF!= flag ) for(sample_counts=0;sample_counts<nbytes;sample_counts++) { fprintf(outfile, "%d,%d\n", (int)ichar-128,(int)qchar-128); flag = fscanf( infile, "%c", &Ichar); flag = fscanf( infile, "%c", &Qchar); 16

17 fclose(infile); fclose(outfile); 17

18 APPENDIX B: ADEX-10H Mixer 18

19 APPENDIX C: AEL9710CSN-50MHz Crystal Clock 19

20 Surface Mount Frequency Mixer Level 17 (LO Power +17 dbm) 10 to 1000 MHz NEW! ADEX-10H Maximum Ratings Operating Temperature -40 C to 85 C Storage Temperature -55 C to 100 C RF Power 200mW IF Current 40mA Pin Configuration LO 6 RF 3 IF 2 GROUND 1,4,5 EVALUATION BOARD P/N: TB-03 Outline Drawing Features EXcellent L-R isolation, 54 db typ. EXcellent flat conversion loss ±0.35 db typ. over entire band low conversion loss, 7.0 db typ. good VSWR, 1.4:1 typ. for LO, 1.6:1typ. for RF, 1.4:1 typ. for IF good performance to 1500 MHz solder plated leads for excellent solderability low profile package, US Patent Applications cellular PCN FREQUENCY (MHz) LO/RF f L - f U IF CONVERSION LOSS* (db) Mid-Band _ m x σ Max. Electrical Specifications Total Range Max. LO-RF ISOLATION (db) L Typ. Min. M Typ. Min. U Typ. Min. CASE STYLE: CD542 PRICE: $3.45 ea. QTY.: (10-49) LO-IF ISOLATION (db) IP3@ center band Typ. (dbm) DC dB Compr.: +14 dbm typ. E= [IP3(dBm)-LO Power(dBm)]/10 *Conversion loss increases 0.5 db when IF is above 150 MHz. L Typ. Min. M Typ. Min. U Typ. Min. E FACTOR L = low range [f L to 10 f L ] M = mid range [10 f L to f U /2] U = upper range [f U /2 to f U ] m= mid band [2f L to f U /2] Outline Dimensions ( ) inch mm A B C D E F G H J K L wt grams Frequency RF MHz LO MHz Conversion Loss (db) LO +17dBm Typical Performance Data Isolation L-R (db) LO +17dBm Isolation L-I (db) LO +17dBm VSWR LO port (:1) LO +17dBm VSWR RF port (:1) LO +17dBm at IF Freq of 30 MHz ADEX-10H CONVERSION LOSS 80 at LO DRIVE of +14/+17/+20 dbm ADEX-10H ISOLATION L-R 2.2 at LO DRIVE of +17 dbm ADEX-10H VSWR CONVERSION LOSS (db) ISOLATION (db) VSWR LO +14dBm LO +17dBm LO +20dBm FREQUENCY (MHz) 30 LO +14 dbm LO +17dBm LO +20dBm FREQUENCY (MHz) 1.0 #LO VSWR #RF VSWR FREQUENCY (MHz) M i n i - C i r c u i t s I N T E R N E T h t t p : / / w w w. m i n i c i r c u i t s. c o m P. O. B o x , B r o o k l y n, N e w Y o r k ( ) F a x ( ) D i s t r i b u t i o n C e n t e r s N O R T H A M E R I C A F a x E UR O P E F a x REV. OR M79465 ED-9813/1 ADEX-10H DJ/TD/CP I S O C E R T I F I E D

21 DatasheetArchive.com Request For Quotation Order the parts you need from our real-time inventory database. Simply complete a request for quotation form with your part information and a sales representative will respond to you with price and availability. Request For Quotation Your free datasheet starts on the next page. More datasheets and data books are available from our homepage: This datasheet has been downloaded from

22