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EFFECTIVITY
CONFIG 4799 Page 32AF 160,162-171,183,184
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(c)
The control word buffer extracts the first 64 bits of data and provides data storage for use by the message generator and coordinate converter. The data word buffer receives the last 1536 bits of range bin data. Weather memory data, sweep line data and test pattern data is managed by the data word buffer.
(d)
The control word buffer accepts and holds the control word bits until they are all clocked into the buffer. The control word is then separated into its scan angle and system status components. The scan angle bits are applied to a coordinate converter. The scan angle is sent to the indicator in a polar coordinate system. The coordinate converter converts the rho, theta coordinates into an X, Y coordinate system. The converter scan angle coordinates are used as address coordinates for the data placed in the weather memory circuits. The remainder of the control word (system status bits) is applied to the message generator. The system status bits are used to address the memory locations of their corresponding messages. The message is then applied to another memory which contains the binary line information to generate that message.
(15) Indicator Front Panel Switch and Control Functions (Fig. 4)
(a) AF 160, 162-171; The indicator front panel contains a pushbutton PWR switch, pushbutton range switches, pushbutton display select, offset display switches and azimuth MKR and display INT control knobs. Operation of the PWR power switch is explained in the electrical power and power control circuits. The functions of the switches and controls on the radar indicator are as follows: 1) Range switches - Controls the range in nautical miles on
the indicator display. There are five settings of 20, 40, 80, 160, and 320. The indicator automatically powers on to the midrange.
2) LFT (left), FWD (forward), and RGT (right) offset display switches - Pressing LFT, indicator displays a left view with origin at the bottom right of CRT. Pressing RGT causes a right view to be displayed with origin at bottom left of CRT. Pressing FWD, a forward view is displayed with the origin at the bottom center. The indicator automatically powers on to the forward view.
3) HOLD select switch - Press the HOLD switch to enable the hold mode of operation, which freezes the image displayed on the CRT. Pressing the HOLD again disables the hold operation and returns the CRT to its normal mapping operation. The indicator automatically powers on with the hold mode disabled. During hold mode, the word HOLD flashes at the top center of the CRT. If hazardous weather is detected while in HOLD operation the message will alternate flashing the operation mode and HOLD message in yellow. For example messages of TURB/HOLD or WX+T/HOLD might be displayed.
EFFECTIVITY
AF 160, 162-171, 183, 184 CONFIG 4 01 Page 33 Sep 25/9434-43-00
4) INT (intensity) control knob - Varies the intensity of video on the display.
5) MKR (marker) control - Varies the intensity of the range and azimuth marks relative to overall video brightness.
6) M/S switch - determines what system display will be shown on the CRT. Pressing the M/S switch selects the slave mode and the CRT will display the same picture as the other indicator. Pressing the M/S switch a second time will return the indicator to the master mode and to its own system. If both indicator M/S switches are selected a STBY mode message is displayed in slot 1 in the upper left-hand corner.
7) AZ switch - when pressed, the azimuth lines are removed from the display. When pressed a second time the azimuth lines reappear. The indicator automatically powers on with azimuth lines present.
(b) AF 183, 184; The indicator front panel contains pushbutton range switches, a M/S master slave switch, offset display switches and azimuth MKR and display INT control knobs. In addition the indicator front panel has three offset display pushbutton switches. The functions of the switches and controls on the radar indicator are as follows: 1) Range switches - Controls the range in nautical miles on the indicator display. There are five settings of 20, 40, 80, 160, and 240. The indicator automatically powers on to the middle range. 2) LFT (left), FWD (forward), and RGT (right) offset display switches - Pressing LFT, indicator displays a left view with origin at the bottom right of CRT. Pressing RGT causes a right view to be displayed with origin at bottom left of CRT. Pressing FWD, a forward view is displayed with the origin at the bottom center. The indicator automatically powers on to the forward view. 3) INT (intensity) control knob - Varies the intensity of video on the display. 4) MKR (marker) control - Varies the intensity of the range and azimuth marks relative to overall video brightness.
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本文链接地址：747飞机维护手册AMM CHAPTER 34 - NAVIGATION 第34章导航3(111)
