{"id":217052,"date":"2025-05-20T20:32:27","date_gmt":"2025-05-20T20:32:27","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=217052"},"modified":"2025-05-20T20:32:29","modified_gmt":"2025-05-20T20:32:29","slug":"design-a-digital-system-whose-output-is-defined-as-logically-low-4","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/20\/design-a-digital-system-whose-output-is-defined-as-logically-low-4\/","title":{"rendered":"Design a digital system whose output is defined as logically low."},"content":{"rendered":"\n<p>Design a digital system whose output is defined as logically low. If the 4 bit inpur binary number is a multiple of 3. Otherwise, the output will be logically high. The output is defined if and only if the input binary number is greater than 2<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Correct Answer:<\/h3>\n\n\n\n<p>To design the digital system, we define the output <code>Y<\/code> as follows:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>If the 4-bit input <code>A = A3A2A1A0<\/code> (where A3 is MSB, A0 is LSB) represents a number greater than 2 <strong>AND<\/strong> is a multiple of 3 \u2192 Output <code>Y = 0<\/code> (LOGICALLY LOW).<\/li>\n\n\n\n<li>Otherwise (either less than or equal to 2, or not divisible by 3) \u2192 Output <code>Y = 1<\/code> (LOGICALLY HIGH).<\/li>\n\n\n\n<li>If the input is \u2264 2 \u2192 Output is undefined.<\/li>\n<\/ul>\n\n\n\n<p>We can implement this with combinational logic using a 4-bit input and a truth table to drive the output logic.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Truth Table:<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Decimal<\/th><th>Binary<\/th><th>&gt;2?<\/th><th>Mod 3 = 0?<\/th><th>Output Y<\/th><\/tr><\/thead><tbody><tr><td>0<\/td><td>0000<\/td><td>No<\/td><td>Yes<\/td><td>X (undef)<\/td><\/tr><tr><td>1<\/td><td>0001<\/td><td>No<\/td><td>No<\/td><td>X (undef)<\/td><\/tr><tr><td>2<\/td><td>0010<\/td><td>No<\/td><td>No<\/td><td>X (undef)<\/td><\/tr><tr><td>3<\/td><td>0011<\/td><td>Yes<\/td><td>Yes<\/td><td>0<\/td><\/tr><tr><td>4<\/td><td>0100<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>5<\/td><td>0101<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>6<\/td><td>0110<\/td><td>Yes<\/td><td>Yes<\/td><td>0<\/td><\/tr><tr><td>7<\/td><td>0111<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>8<\/td><td>1000<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>9<\/td><td>1001<\/td><td>Yes<\/td><td>Yes<\/td><td>0<\/td><\/tr><tr><td>10<\/td><td>1010<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>11<\/td><td>1011<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>12<\/td><td>1100<\/td><td>Yes<\/td><td>Yes<\/td><td>0<\/td><\/tr><tr><td>13<\/td><td>1101<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>14<\/td><td>1110<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><tr><td>15<\/td><td>1111<\/td><td>Yes<\/td><td>No<\/td><td>1<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation (300+ words):<\/h3>\n\n\n\n<p>This digital system requires a combinational logic circuit with a 4-bit binary input and a single binary output. The core function of the system is to determine whether a binary input value meets specific conditions and set the output accordingly.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>1. Understanding the Input Conditions:<\/strong><\/h4>\n\n\n\n<p>The input is a 4-bit binary number, meaning it can represent values from 0 to 15 (decimal). The system should only define the output <strong>if the input value is greater than 2<\/strong>. Therefore, values 0, 1, and 2 are considered <strong>undefined<\/strong> and need not be processed in the logic.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>2. Multiples of 3:<\/strong><\/h4>\n\n\n\n<p>The system must recognize if the valid input (greater than 2) is a multiple of 3. In the decimal range of 3 to 15, the multiples of 3 are:<br><strong>3, 6, 9, and 12<\/strong>.<\/p>\n\n\n\n<p>If the input matches one of these values, the output <code>Y<\/code> must be <strong>logically LOW (0)<\/strong>. For all other defined values (greater than 2 but not divisible by 3), the output should be <strong>logically HIGH (1)<\/strong>.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>3. Digital Implementation:<\/strong><\/h4>\n\n\n\n<p>To implement this in digital logic:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use a <strong>comparator<\/strong> to check if the input is greater than 2.<\/li>\n\n\n\n<li>Use a <strong>modulus detector<\/strong> (e.g., combinational logic that outputs true if a number mod 3 is 0).<\/li>\n\n\n\n<li>Combine these with an <strong>AND gate<\/strong> to check if both conditions are met.<\/li>\n\n\n\n<li>Use a <strong>NOT gate<\/strong> to invert the result so that the output is low when both conditions are true.<\/li>\n<\/ul>\n\n\n\n<p>Alternatively, a <strong>ROM-based solution<\/strong> or <strong>PLD (Programmable Logic Device)<\/strong> can use a lookup table matching the truth table above. This approach is efficient when dealing with small input spaces like a 4-bit system.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Conclusion:<\/strong><\/h4>\n\n\n\n<p>This digital logic system is useful for control applications where actions depend on numeric thresholds and specific divisibility. Designing the output based on arithmetic properties like &#8220;greater than&#8221; and &#8220;multiple of&#8221; allows for sophisticated decision-making in digital electronics.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Design a digital system whose output is defined as logically low. If the 4 bit inpur binary number is a multiple of 3. Otherwise, the output will be logically high. The output is defined if and only if the input binary number is greater than 2 The Correct Answer and Explanation is: Correct Answer: To [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-217052","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/217052","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=217052"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/217052\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=217052"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=217052"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=217052"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}