Robin Sharama's Success lessons

C Programming Questions – Part 1

1. W hat do curly braces denote in C? Why does it make sense to use curly brac es to surround the body of a function? Answer: The curly braces denote a block of code, in which variables can be declared. Variables declared within the block are valid only until the end of the block, marked by the matching right curly brace ’}’. The body of a function is one such type of block, and thus, curly braces are used to describe the extent of that block . 2.Describe the difference between the literal values 7, "7", and ’7 ’ ? Answer: The first literal is integer 7.Second literal is null terminated string value '7'.Third literal is character '7' having ASCII character code (55). 3. Consider the statement double ans = 10.0+2.0/3.0−2.0∗2.0; Rewrite this statement, inserting parentheses to ensure that ans = 11.0 upon evaluation of this statement ? Answer: double ans = 10.0+2.0/ (( 3.0−2.0 ) ∗2.0 ) ; 4 .C...

C Programming Questions - Part 2

1) How do you determine the size and range of the following data types ? char unsigned char short int unsigned int unsigned long float Ans:- limits.h header file defines the minimum and maximum range macros for each of the data types , sizeof(datatype) returns the number of bytes used by the datatype in current machine. 2) Write logical expressions that tests whether a given character variable c is lowercase letter uppercase letter digit white space(includes space,tab,newline) Ans:- lowercase letter = (c >= 'a' && c <= 'z') uppercase letter = (c >= 'A' && c <= 'Z') digit = (c >= '0' && c <= '9') white space(includes space,tab,newline) = (c == ' ' || c == '\t' || c == '\n') 3) Consider unsigned int val=0xCAFE; Write expressio...

Sampling and FFT Size derivation in LTE

Sampling and FFT Size derivation in LTE Ts = 1 / (15000 x 2048) seconds, which corresponds to the 30.72 MHz sample clock for the 2048 point FFT used with the 20 MHz system bandwidth. In the frequency domain, the number of sub-carriers N ranges from 128 to 2048, depending on channel bandwidth with 512 and 1024 for 5 and 10 MHz, respectively, being most commonly used in practice. The sub-carrier spacing is ∆f = 1/T u = 15 kHz. The sampling rate is fs = ∆f · N = 15000 N. This results in a sampling rate that’s multiple or sub-multiple of the WCDMA chip rate of 3.84 Mcps: LTE parameters have been chosen such that FFT lengths and sampling rates are easily obtained for all operation modes while at the same time ensuring the easy implementation of dual-mode devices with a common clock reference. Sampling frequency is Multiple's of 2, For 15 Mhz Bandwidth - Sampling Frequency = 23.04 (6 * 3.84). FFT SIZE = S...

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