Technical Specifications ( You probably do NOT need to read this ) This document contains technical information, generally of interest but not neccesarily useful. The following information is subject to change w/o notice, as we deem neccesary. The "accuracy factor" is a number that is the percentage of accurate reproduction that a particular format is capable of, given optimum (closed circuit, p5, etc) conditions, and image material containing information with 1 pixel transistions both horizontally and vertically in the top 1/4 of the lumanence range for that mode. Most formats, with the exception of the Robot composite formats, can transfer any kind of image information intact given optimum conditions. The "recovery factor" is a number that is made up of 1 point for each of the following capabilities: a; after temp loss of signal, mode always maintains horiz position info b; after temp loss of signal, mode always maintains vert position info c; after temp loss of signal, mode always maintains color info d; after temp loss of signal, mode always maintains luma info For color modes, a "4" is optimum; less means that the worse signal conditions become, the more torn up the image will be in various ways. For black and white modes, a 3 is optimum - obviously there is no concern for color accuracy with a black and white mode, only the luma matters. SSTV format specifications, as supported by the AVT: 8.5 sec B&W; - Original SSTV mode, since time immemorial. Sorta. 128 horizontal by 128 vertical. 60.666 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync 64 grey levels receive 64 grey levels transmit 16 grey levels display 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 7.08 sec B&W; - Original SSTV mode, at 50 hz rates for Europe. 128 horizontal by 128 vertical. 60.666 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync 64 grey levels receive 64 grey levels transmit 16 grey levels display 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 17(a) sec B&W; - As per WA7WOD's 300c modification of the Robot 400 128 horizontal by 256 vertical. 49.33 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync 64 grey levels receive 64 grey levels transmit 16 grey levels display 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 17(b) sec B&W; - As per the Microcraft Videoscan 1000 256 horizontal by 128 vertical. 121.333 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync 64 grey levels receive 64 grey levels transmit 16 grey levels display 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 34 sec B&W; - As per the Microcraft Videoscan 1000 256 horizontal by 256 vertical. 121.333 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync 64 grey levels receive 64 grey levels transmit 16 grey levels display 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 8 sec B&W; - As per the Robot 400c, 450c, and 1200c 128 horizontal by 120 vertical. 60.666 ms/scan line 6.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec 64 grey levels receive 64 grey levels transmit 16 grey levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 12 sec B&W; - As per the Robot 400c, 450c, and 1200c 128 horizontal by 120 vertical. 91 ms/scan line 9.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec 64 grey levels receive 64 grey levels transmit 16 grey levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 24 sec B&W; - As per the Robot 400c, 450c, and 1200c 256 horizontal by 240 vertical. 94.0 ms/scan line 6.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec 64 grey levels receive 64 grey levels transmit 16 grey levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 36 sec B&W; - As per the Robot 400c, 450c, and 1200c 256 horizontal by 240 vertical. 141.0 ms/scan line 9.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec 64 grey levels receive 64 grey levels transmit 16 grey levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 100 Recovery factor: 2 (a,d) 12 sec composite color; - As per the Robot 400c, 450c, and 1200c 128 horizontal by 120 vertical. 94 ms/scan line 6.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec decode 64 horizontal and 60 vertical color cells, over 128x120 luma cells 64 luma/chroma levels receive 64 luma/chroma levels transmit 16 luma/chroma levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 25 Recovery factor: 2 (a,d) 24 sec composite color; - As per the Robot 400c, 450c, and 1200c 128 horizontal by 120 vertical. 191 ms/scan line 9.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec decode 64 horizontal and 120 vertical color cells, over 128x120 luma cells 64 luma/chroma levels receive 64 luma/chroma levels transmit 16 luma/chroma levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 50 Recovery factor: 2 (a,d) 36 sec composite color; - As per the Robot 400c, 450c, and 1200c 256 horizontal by 240 vertical. 144 ms/scan line 6.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec decode 128 horizontal and 120 vertical color cells, over 256x240 luma cells 64 luma/chroma levels receive 64 luma/chroma levels transmit 16 luma/chroma levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 25 Recovery factor: 2 (a,d) 72 sec composite color; - As per the Robot 400c, 450c, and 1200c 256 horizontal by 240 vertical. 291 ms/scan line 9.0 ms horizontal sync 300 ms mode/memory encoded vertical sync as per spec decode 128 horizontal and 240 vertical color cells, over 256x240 luma cells 64 luma/chroma levels receive 64 luma/chroma levels transmit 16 luma/chroma levels display 1200 Hz nominal bandwidth (1100-2300 hz) Accuracy factor: 50 Recovery factor: 2 (a,d) 25.5 sec line sequential color; - As per WA7WOD's 3000c 400 mod 128 horizontal by 128 vertical. 60.666 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync mode specifies 4096 colors 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 0 () 51.0 sec line sequential color; - As per WA7WOD's 3000c 400 mod 128 horizontal by 256 vertical. 60.666 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync mode specifies 4096 colors 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 0 () 102.0 sec line sequential color; - As per WA7WOD's 3000c 400 mod 256 horizontal by 256 vertical. 121.333 ms/scan line 6.0 ms horizontal sync 30 ms vertical sync mode specifies 4096 colors 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 0 () 24 sec line sequential red sync-locked color; - Volker-Wrasse 128 horizontal by 128 vertical. 60.666 ms/scan line 12(red), 6(green), and 6(blue) ms horizontal sync 30 ms vertical sync mode specifies 4096 colors 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 3 (a,c,d) 48 sec line sequential red sync-locked color; - Volker-Wrasse 128 horizontal by 256 vertical. 60.666 ms/scan line 12(red), 6(green), and 6(blue) ms horizontal sync 30 ms vertical sync mode specifies 4096 colors 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 3 (a,c,d) 94 sec line sequential red sync-locked color; - Volker-Wrasse 256 horizontal by 256 vertical. 121.33 ms/scan line 12(red), 6(green), and 6(blue) ms horizontal sync 30 ms vertical sync mode specifies 4096 colors 1100 Hz nominal bandwidth (1200-2300 hz) Accuracy factor: 100 Recovery factor: 3 (a,c,d) 24 sec, wide SLP Color; - AVT mode 128 horizontal by 128 vertical. 187.5 ms/scan line - 62.5 ms/128 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1900 Hz start bit \ 1600 Hz ONE bits 9.765625 ms/bit 2200 Hz ZERO bits / min luma at 1500 Hz (64 detected levels) max luma at 2300 Hz 800 Hz nominal bandwidth (1500-2300 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 90 sec, wide SLP Color; - AVT mode 256 horizontal by 240 vertical. 375 ms/scan line - 125 ms/256 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1900 Hz start bit \ 1600 Hz ONE bits 9.765625 ms/bit 2200 Hz ZERO bits / min luma at 1500 Hz (64 detected levels) max luma at 2300 Hz 800 Hz nominal bandwidth (1500-2300 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 93.75 (94) sec, wide SLP Color; - AVT mode 320 horizontal by 200 vertical. 468.75 ms/scan line - 156.25 ms/320 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1900 Hz start bit \ 1600 Hz ONE bits 9.765625 ms/bit 2200 Hz ZERO bits / min luma at 1500 Hz (64 detected levels) max luma at 2300 Hz 800 Hz nominal bandwidth (1500-2300 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 187.5 (188) sec, wide SLP Color; - AVT mode [not used at this time] 320 horizontal by 400 vertical. 468.75 ms/scan line - 156.25 ms/320 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1900 Hz start bit \ 1600 Hz ONE bits 9.765625 ms/bit 2200 Hz ZERO bits / min luma at 1500 Hz (64 detected levels) max luma at 2300 Hz 800 Hz nominal bandwidth (1500-2300 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 24 sec, narrow SLP Color; - AVT mode 128 horizontal by 128 vertical. 187.5 ms/scan line - 62.5 ms/128 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1900 Hz start bit \ 1700 Hz ONE bits 9.765625 ms/bit 2100 Hz ZERO bits / min luma at 1700 Hz (32 detected levels) max luma at 2100 Hz 400 Hz nominal bandwidth (1700-2100 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 90 sec, narrow SLP Color; - AVT mode 256 horizontal by 240 vertical. 375 ms/scan line - 125 ms/256 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1900 Hz start bit \ 1700 Hz ONE bits 9.765625 ms/bit 2100 Hz ZERO bits / min luma at 1700 Hz (32 detected levels) max luma at 2100 Hz 400 Hz nominal bandwidth (1700-2100 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 93.75 (94) sec, narrow SLP Color; - AVT mode 320 horizontal by 200 vertical. 468.75 ms/scan line - 156.25 ms/320 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1900 Hz start bit \ 1700 Hz ONE bits 9.765625 ms/bit 2100 Hz ZERO bits / min luma at 1700 Hz (32 detected levels) max luma at 2100 Hz 400 Hz nominal bandwidth (1700-2100 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 187.5 (188) sec, narrow SLP Color; - AVT mode [not used at this time] 320 horizontal by 400 vertical. 468.75 ms/scan line - 156.25 ms/320 pels each of red, green, and blue data no horizontal sync no vertical sync 32 instance 16 bits/burst digital header, mode and timing info 1700 Hz start bit \ 1600 Hz ONE bits 9.765625 ms/bit 2100 Hz ZERO bits / min luma at 1700 Hz (32 detected levels) max luma at 2100 Hz 400 Hz nominal bandwidth (1500-2300 hz) Accuracy factor: 100 Recovery factor: 4 (a,b,c,d) 10 minute B&W; - 120 lpm FAX 1024 horizontal by 1200 vertical. .5 Hz/scan line no horizontal sync no vertical sync 64 grey levels receive 64 grey levels transmit 16/4 grey levels display 800 Hz nominal bandwidth (1500-2300 hz) Accuracy factor: 100 Recovery factor: 3 (a,b,d) 20 minute B&W; - 60 lpm FAX 1024 horizontal by 1200 vertical. 1 Hz/scan line no horizontal sync no vertical sync 64 grey levels receive 64 grey levels transmit 16/4 grey levels display 800 Hz nominal bandwidth (1500-2300 hz) Accuracy factor: 100 Recovery factor: 3 (a,b,d) Autostart Capabilities Robot Autostart: Using the VIS signal, the new Robot modes encode the memory (R, G, B, or composite) resolution, and the speed of the transmission that is coming. The AVT system will respond accordingly if it aqquires a VIS signal accurately while in the Robot AUTO mode. In this context, VIS means "Vertical Interval Signal". SLP Autostart Using the digital header, the SLP modes encode the speed, resolution, and precise start time of the oncoming transmission. When in any SLP receive mode, the AVT system will autostart if it aqquires a header accurately. FAX Autostart FAX stations usually send a "sweep" from black to white at a 300 hz rate. If the AVT system detects such a signal while waiting for a FAX transmission, it will proceed to a phasing state. FAX Autophase Once in the phasing state, a 4th order digital filter is applied to the incoming signal, which is then monitored for a black condition lasting at least the length of 1/2 scan line at the selected line rate. Once this has been detected, the system locates and marks, timewise, the position of the white phasing pulse. This is done repeatedly; if two phasing pulses are found to match starting times within 1.9 ms, the AVT system locks that time interval to the beginning of a scan line, and reception commences. File Formats: Low-resolution color: 8192 of red, 128h 128v 6 bits/pixel/byte, 8192 of green, 128h 128v 6 bits/pixel/byte, 8192 of blue, 128h 128v 6 bits/pixel/byte hi-resolution color: 65536 of red, 256h 240v 6 bits/pel/byte, 65536 of green, 256h 240v 6 bits/pel/byte 65536 of blue, 256h 240v 6 bits/pel/byte AVT mode, high: 64000 of red, 320h 200v 6 bits/pel/byte, 64000 of green, 320h 200v 6 bits/pel/byte, 64000 of blue, 320h 200v 6 bits/pel/byte AVT mode, full: 128000 of red, 320h 400v 6 bits/pel/byte, 128000 of green, 320h 400v 6 bits/pel/byte, 128000 of blue, 320h 400v 6 bits/pel/byte FAX mode: 153600 of MS bit, 1024h 1200v 8 pels/byte 153600 of NMS bit, 1024h 1200v 8 pels/byte 153600 of NLS bit, 1024h 1200v 8 pels/byte 153600 of LS bit, 1024h 1200v 8 pels/byte IFF Images; Standards as per CBM RKM v1.2, Addison-Wesly Notes on AVT modes: Advantages of the Synchronous Line Phase (SLP) color modes: 1; Images always maintain color accuracy - no phase artifacts 2; Images always maintain horizontal positioning - no bending, shifting 3; Images always maintain vertical positioning - no too short/long images 4; Images always start at the top - never misses home up info in valid image 5; More efficient use of the spectrum - 3 stations in the space of 1 6; Narrower bandwidth images enable tighter filtering, QRM/QRN resistance 7; Narrower bandwidth images offer more effective power output 8; 32x redundant digital header overcomes most any interference All of these factors combine to offer the following tangible results to the user of these modes: *Extremely high performance under good to average signal conditions *Good quality images under marginal signal conditions *High immunity to multipath, QRM, QRN, splatter, filtering, and mistuning *Repeatable images - send them through 10 stations - they STILL look good! *So accurate, can be used to transfer 3 B&W images at one time. *You use less spectrum on transmit, you bother others less... *You use less spectrum on receive, others bother YOU less!