Quantcast Figure 2-52.Block diagram of quantizer and pcm coder.

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
2-52 Figure 2-52.—Block diagram of quantizer and pcm coder. The pcm demodulator will reproduce the correct standard amplitude represented by the pulse-code group. However, it will reproduce the correct standard only if it is able to recognize correctly the presence or absence of pulses in each position. For this reason, noise introduces no error at all if the signal-to-noise ration is such that the largest peaks of noise are not mistaken for pulses. When the noise is random (circuit and tube noise), the probability of the appearance of a noise peak comparable in amplitude to the pulses can be determined. This probability can be determined mathematically for any ration of signal-to-average- noise power. When this is done for 10 5 pulses per second, the approximate error rate for three values of signal power to average noise power is: 17 dB — 10 errors per second 20 dB — 1 error every 20 minutes 22 dB — 1 error every 2,000 hours Above a threshold of signal-to-noise ration of approximately 20 dB, virtually no errors occur. In all other systems of modulation, even with signal-to-noise ratios as high as 60 dB, the noise will have some effect. Moreover, the pcm signal can be retransmitted, as in a multiple relay link system, as many times as desired, without the introduction of additional noise effects; that is, noise is not cumulative at relay stations as it is with other modulation systems. The system does, of course, have some distortion introduced by quantizing the signal. Both the standard values selected and the sampling interval tend to make the reconstructed wave depart from the original. This distortion, called QUANTIZING NOISE, is initially introduced at the quantizing and coding modulator and remains fixed throughout the transmission and retransmission processes. Its magnitude can be reduced by making the standard quantizing levels closer together. The relationship of the quantizing noise to the number of digits in the binary code is given by the following standard relationship: Where: n is the number of digits in the binary code


Electrical News
EEVblog #737 – World’s Biggest Collection Of Electronics Components
Dave uncovers that has to be one of the world’s...
eevblog.com
ARM Gives Peek at Road Map
ARM disclosed new details of its A72, including three functional...
eetimes.com
Cypress Expands Error Correcting Code For SRAM
As overall SRAM market shrinks, Cypress sees uptick in automotive,...
eetimes.com
EUV Deal Raises Questions
ASML announced it struck a deal to sell 15 EUV...
eetimes.com
Make Field-oriented Motor Control Affordable
Shaft sensors and their wiring make field-oriented motor control pricey,...
eetimes.com
Why Connect Cars?
EE Times will host a radio show on "Why Connect...
eetimes.com
Time Flies Like an Arrow & Fruit Flies Like Bananas
Using a computer to translate something like a technical article...
eetimes.com
NXP-Freescale Mega Merger on Track
Five companies, aside from NXP, were in talks with Freescale,...
eetimes.com
Basic University Research Key to Industry Progress
A basic, precompetitive research base is required to continue to...
eetimes.com
MEMS Seeks its Moore's Law
MEMS provide an alternative route to scaling technology beyond Moore's...
eetimes.com
Wireless Charging Gets Universal Antenna
NuCurrent believe the company's 50 patents in areas such as...
eetimes.com
Friday Quiz: EMI and EMC
EDN's Designer's Guide to Electromagnetic Compatibility, written by Bill Kimmel...
eetimes.com
EEVBlog #736 – World’s First IR Thermal Camera Watch
A quick hack turns a Flir TG165 Thermal camera into...
eevblog.com
Wave of 100th Birthday Celebrations Rolls Around the World
Following the party Max's family held to celebrate what would...
eetimes.com
Qualcomm Seeking Options Beyond Apple, Samsung
Qualcomm's recent earnings reports suggest significant vulnerabilities. Qualcomm is heavily...
eetimes.com
Elvis Sees All in Russia
A Russian company claims it has the first Russian designed...
eetimes.com
Smartwatch Uptick in Mobile Slump
Smartwatches could grow to sales of 400 million units a...
eetimes.com
8 Views of Security from RSA
Security was in focus at RSA Conference with top cryptographers,...
eetimes.com
Electricity, Energy and Global Warming By the Numbers, Part 2
Numerous factors contribute to climate change. In Part 2, we...
eetimes.com
10 Trailblazing Companies For Women In IT
On the following pages, we'll take you beyond the tech...
eetimes.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +