1、MIL-D-287366( EC) AMENDMENT 5 10 June 1977 SUPtRStOING AMENDMENT 4 30 July 1973 MILITARY SPECIFICATION DECODER GROUP, AN/UPA-Sg(V) IFF MK XII (SIF), WITH ACTIVE READOUT AND ASSOCIATED MODIFICATION TO INDICATOR (PPI) This amendment forms a part of Military Specification MIL-D-28736B(EC), dated 20 Dec
2、ember 1971. Page 6 3.2.3.3: Add the following to the end of the paragraph: furnished to hold the chassis while extended for maintenance. and effective for horizontally mounted decoders, as well as those mounted up to.and including +90 degrees from horizontal. “A positive locking device shall be This
3、 locking device shall be safe Page 10 Delete and substitute: 3.4.10, first sentence: “The combined weight of the decoder and active readout unit shall not exceed 32 pounds“. Delete last sentence. 3.4.13: “3.4.1.3 Mounting provisions for brackets and mounting plates. Mounting brackets and rnount- Pro
4、posed mounting provisions shall be approved- Delete and substitute the following: ing plates shal7 be furnished by the contractor. by the comnand or agency concerned prior to use (see 6.3).“. Page 14 3.4.15.10.4, Delete and substitute: 3.4.15.10.4 Identification tag decode tolerance. Mode 1, 2, 3/A,
5、 4 and C tag decoders shall produce a tag decode when the proper pulse configuration (nominal pulse width) is received over + 0.35 psecond of the ideal spacing. be produced. II. For f 0.65 psecond from ideal spacing, no decode shall * Add the following new paragraph: “3.4.15.10.5 Decode reset. In th
6、e absence of reset pulses, it shall be possible to reset the decode from the PI pulse of the identification tags. .This format of operation shall be selected by a solderless jumper link or one circuit card within the basic decoder. 3.4.15.12: Delete O-+ 0.55 psecond“ and substitute 9 0.65 pseconds.“
7、. . 3.4.15.15, Delete all but the first sentence and add “(see 3.4.27.)“ NOTE: the previous amendment tere made. no liability-whatsoever for any inaccuracies in these notations. cautioned to evaluate the requirements of this document based on the entire content irrespective of the marginal notations
8、 and relationship to the previous amendment. The margins of this amendment are marked with an asterisk to indicate where changes from This was done as a convenience only and the Government assumes Bidders and contractors are FSC 5895 Provided by IHSNot for ResaleNo reproduction or networking permitt
9、ed without license from IHS-,-,-MIL-D-287366 (5) 5 7997906 0354V2 7 MIL-D-28736B( EC) AMENDMENT 5 - Page 15 3.4.18: Add as first sentence: “Controls, indicators, and panel layouts shall be submitted to the Comnand or Agency con- 3.4.18(a)(8): Delete and substitute: “3.4.18(a)(8) A continuously varia
10、ble control, variable from 1 to 20 nautical miles, used The unit shall cerned for approval (see 6.3).“. to increase and decrease the range (length) of the target sector gate. The control may be accom- plished in a maximum of two steps by use of a solderless link to select the operating range. The tw
11、o ranges to be selected shall be 1-10 nautical miles and 2-20 nautical miles. be shipped with the link in the 2 to 20 nautical mile range position.“. * 3.4.18(a)(ll): Delete and substitute: “3.4.18(a)( 11) Bracket on-off-mix switch; a three position switch to select bracket decode out put. Page 16 3
12、.4.18(b)(16): Delete and substitute: “3.4.18(b)(16) Spare video connector: quantity one, wired as an input to mixer amplifier.“. Page 17 3.4.23: Add the following: . “For code video trains with pulse width between 0.30 microseconds and 0.45 microseconds the output c0d.e pulse width shall be 0.45 plu
13、s or minus 0.10 microseconds. with pulse width greater than 0.45 microseconds the code video output pulse width shall be equal to the input pulse width with a tolerance of plus or minus 0.10 microseconds.“. For code video trains Page 18 3.4.27, Delete and substitute: “3.4.27 Mode enable outputs and
14、controls. Provisions shall be made to provide six separate mode enable outputs for challenge control of Modes 1, 2, 3/A, C, 4, and Mode 4 override. The mode outputs shall have the following enable control provisions: enable contro links. Mode 4 (a) The mode enable outputs for Modes 1, 2, 3/A, C, and
15、 4 shall have separate enable The selections shall be solderless s with any combination of these controls selectable. (b) The Mode 4 and Mode 4 override outputs shall be simultaneously enabled when the override control is placed in the momentary position. (c) (d) When the Mode 4 override control is
16、in the sector position, the Mode 4 and Mode 4 Using the mode enable outputs for Modes 1, 3/A and 4, provide by means of solder- override outputs shall be simultaneously enabled by and for the duration of the azimuth gate. less links three mode enable outputs for independent mode enable control of th
17、e six modes. The three wire output mode enable control circuits shall consist of diodes connected as shown in Figure 5 with the combined Modes 1 and 2 on the Mode 1 output line, combined Modes 3/A and C on the Mode 3/A output line, and combined Mode 4 and Mode 4 override on the Mode 4 output line.“.
18、 Page 2 of 6 f Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-D-28736B( EC) AMENDMENT 5 3.4.29: Delete and substitute the following: * “3.4.29 Self-test. A self-test feature shall be provided by front panel selector switch(s) for the decoder gro
19、up. configuration on a one code at a time basis sha.ll be considered adequate to test the passive, and active decode function and the display. layer and emergency alam function, as described.herein. provided for conversion of the inserted code to attitude in feet for the active readout display test
20、of the Mode C conversion. This test switch shall .be used for front panel test control and shall have three positions designated SIF, OFF and Mode C. shall be approved by the comand or agency concerned prior to use (see 6.3). feature is selected, it shall not be necessary to set the read gate switch
21、 to ON in order to perform active testing. Insertion, decoding, and display of the front panel selected test code This test feature shall also test the selected attitude Front panel selection shall.also be The design of this self-test feature When the self-test Page 19 functionalmiagrams of figures
22、2 and 3 which are supplied for information.only and are not represented as complete in all particulars of the requirements herein. Definitions used in this specification shall be as detailed in MIL-STD-751 (see 6.4). coded replies, develop passive and bracket decode outputs, and display the active r
23、eadout of reply code-s. IFF target. bracket decode, and selected targets with passive decode. The passive-decode targets shall be stretched with respect to the bracket targets. desired, the selected target shall be stretch.ed in pulse width for presentation. bracket or selected targets are used sepa
24、rately, normal decode pulse width shall be presented. When all brackets are selected, brackets shall be displayed for all video replies reaching the decoder, not merely those associated with modes enabled at the decoder itself. The degarble circuitry shall reduce the probability of false target disp
25、lay or false readout to a minimum. pulse regeneration or trigger circuitry shall be enabled until a decision has been made by the decoder that a valid reply pulse is present. A valid pulse is one which has a pulse width of 0.30 seconds or more. Mode 4 continuous will be challenged in readout gate az
26、imuth only. 4 selected by the Mode switch will be similar to other interlaced modes. selected SIF codes would be stretched, Mode 4 and bracket decode, would not be stretched. * 3.6 Function, The decoder group shall utilize, as a general guide for basic design, the The decoder group shall process SIF
27、 The active readout feature will serve for rapid code identification of an unknown There shall be the capability to display simultaneously all SIF targets by means of When both selected target and brackets are When either No Mode In this mode of operation Page 21 * 3.6.1.3(b): Delete and substitute:
28、 “(b) Bracket video on all mode bracket video. Page 22 3.6.1.5: Delete the last sentence and substitute the following: “The degarbling feature shall be operative during active readout except when passive decode is connected to the early decode line; however, a simplified technique such as card rever
29、sal shall be provided to allow enabling or disabling the degarbling during passive type of operation.“. Page 23 * 3.6.1.6.2: Add the following new subparagraph: “(c) shall not interfere with normal operation of the decoder, nor shall it be passed for display.“ * 3.6.1.6.3: Add the following new subp
30、aragraph: “(d) on a separate cable.“ A positive or negative dc bias of up to 2.5 volts may be present on this input. This bias Accept unseparated video with or without resets on one cable and mode identification tags Page 3 of 6 Provided by IHSNot for ResaleNo reproduction or networking permitted wi
31、thout license from IHS-,-,-MIL-0-28736B( EC) AMENDMENT 5 * 3.6.1.6.4.1: Add the following new subparagraph: “(c) Range strobe output of a PPI is frequently counted down two or more times with respect to IFF sweeps. range determined by the most recent range strobe, and shall maintain this position un
32、til new range strobe information is provided from the PPI. This automatic range strobe function shall require no link settings or adjustmentsfor operation. In these cases, the decoder shall automatically continue the gating function at the Page 24 3.6.1.8: Delete and substitute: “3.6.1.8 Individual
33、pulse shift. When any nominalpulse (0.45 psecond width) of the correct For a pulse shift of f 0.18 pseconds, the configuration is shifted from its nominal position by k 0.15 pseconds, the decoder shall provide an output for at least 99 percent of the replies received. decoder shall provide an output
34、 for at least 90 percent of the replies received. For a pulse shift . of f 0.40 riseconds the decoder shall provide outputs for less than 10 percent of the replies received. When the input pulse width is decreased to 0.30 pseconds, the limits shall be the same as those specified above for 0.45 pseco
35、nd pulses. When the pulse width is increased to 1.0 pseconds, the reject limit shall increase from t 0.40 pseconds to t 1.0 useconds, The accept limits for 1.0 pseconds pulses shall be the same as that specified for 0.45 psecond pulses.4t. * 3.6.1.9: Delete and substitute: “3.6.1.9 Extraneous pulses
36、. For extraneous pulses occurring within f 0.15 pseconds of a For extraneous pulses which occur at f 0.18 riseconds nominal space position in a correctly decoded reply train, the decoder shall provide outputs for less than 1 percent of the reply trains. from a nominal space position,.the decoder sha
37、ll provide outputs for less than 10 percent of the reply trains. the decoder shall provide outputs for at least 90 percent of the reply trains.“. For extraneous pulses which occur greater than f 0.40 riseconds from a space position . 3.6.1.10, fourth line: Delete “-3 “10 percent decrease in the deco
38、de ing: Page 25 dB change in the decode amplitude“ and substitute the follow- pul se repet i tion frequency. I. Page 26 * 3.6.1.15: Delete and substitute: “3.6.1.15 When sector challenge is used, targets located within the azimuth width of the sector gate shall be actively displayed. With the passiv
39、e challenge switch on, continuous challenge shall be provided; and the IFF target display shall not be affected by the target sector gate. either switch position, active readout of target replies is enabled only for time intervals equivalent to the size of the displayed gate. The active readout shal
40、l be retained on the channels until reset. mitting reset time of a minimum of one second to a maximum of ten seconds following the active decode display. readout hold duration is still on, the following actions shall take place: In A continuously variable internal adjustment shall be provided for ac
41、tive readout hold duration per- For cases in which the antennas high rpm causes a second readout gate while the (a) Codes held and displayed on.the active readout shall be extinguished. (b) The active readout shall be reset. (c) Active readout shall be provided for target replies within the second r
42、eadout gate. (d) Active readout of these new targets within the second readout gate shall continue for the full readout hold duration, or until a third readout gate occurs, upon which steps (a), (b), (c) and (d) shall be repeated.“ Page 4 of 6 Provided by IHSNot for ResaleNo reproduction or networki
43、ng permitted without license from IHS-,-,- MIL-D-2873bB (5) 58 W 777770b 0159985 2 MIL-D-287366( EC) AMENDMENT 5 Page 27 * 3.6.1.16: Add the following to.the end of the paragraph: “The sector gate shall operate with antennas running at speeds from 3 to 65 rpm. For antenna speeds within this range, t
44、he sector gate shall operate within the following tolerances: (a) Sector gate size shall vary by no more than 5 5 degrees (b) Sector gate position shall vary if no more than k 3 degrees (c) Position is defined by the superposition of sector gate leading edge with PPI cursor bearing leading edge.“ Pa
45、ge 31 3.6.4.2.8, last sentence: Delete and substitute the following: “NO circuitry shall be used in the alarm decoding circuits which might cause the effectiveness of the alarm to be decreased.“. Page 32 3.6.412.8.1, firstline: Delete “reduce the effectiveness of many“ and substitute minimize“. Page
46、 43 6.3: “(k) “(1) Contrqls, indicators, and panel layouts (see 3.4.18). “(m) Self test feature (see 3.4.29).“. Add the following new subparagraphs: Mounting provisions for brackets and mounting plates (see 3.4.13). Page 50 * Figure 4.: Add the following and delete the last vertical line on the righ
47、t under the displayed video column: DECODE OFF _ U SAL STRTCH BRKT CODE .DISPLAYED VIDEO al 1 modes being OFF 3td brackets for 25mr ALL challenged by the interrogator Page 51 Add attached new figure. Preparing activity: (Project 5895-N260) Navy - EC *US. GOVERNMENT PRINTING OFFICE: 1977-7050n)/4201
48、Page 5 of 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-D-B736B( EC) AMENDMENT 5 r 1 I Mode 1 hl Mode 1 Mode 2 Mode2 OUTPUT t- Id MndP r5 I. ; PId: : override Mode 4 ove- FIGURE 5. Mode enable outputs. To DECODER CONTROL SUITCXS Page 6 of 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
