Problems
1. Define the term "sample" as it applies to digital systems.
-A sample is a "snap-shot" in time of an analog signal. It has a finite resolution or accuracy an represents the value of the analog signal at only one instant in time.
2. Define the term "sampling rate" as it applies to digital system
A sampling rate is the rate (usually in samples per second) at which the digital system takes its samples or "snap-shots". If a sampling rate is 10 samples/second, then the digital system measures the analog value ten times every second.
3. What are the two primary problems that sampling could cause?
Firstly, if the Sampling too slowly may cause the digital system to miss "faster" details of an analog signal.
Secondly, if the resolution or accuracy of the digital system that is measuring the analog signal is too low, the system may not be able to discern the difference between two samples.
4. Name the three parts of the system used to input an analog signal
into a digital system and describe their purpose.
There is System that is used to get/catch/sense analog signal in desired environment in our device/s like PC/phone via Conversion System of analog to digital signal that use a SENSOR to catch analog signal and it is amplified and refined before it goes to ADC or analog-to-digital converter.
Initially the captured analog signal is first weak and noisy before it will be conditioned to be passed on (ADC) for analog to digital converter.
Secondly, the captured analog signal will be conditioned for amplifying or refining analog signal (weak and noisy analog signal), the analog signal must be amplified in order to reach its destination and after it is amplified the weak and noisy analog signal will be strong and clean analog signal, enough to be converted to digital signal.
Lastly, the strong and clean analog signal will be converted to analog to digital signal. The results of this system are viewed like the table of numbers and 0’s and 1’s that is in computer readable form.
5. Name four benefits of a digital system over an analog system.
There are benefits to using data in a digital format rather than analog.
First, if an analog signal is transmitted over long distances. The noise that is attached to the signal will get amplified and converted to digital signal.
Secondly, noise cannot attach itself to a digital signal. Once an analog signal has been converted to a sequence of numbers, the signal's characteristics remain the same as long as the numbers don't change.
Thirdly, the benefit that once a signal is turned into a sequence of
numbers, mathematical algorithms can be used to operate on the data.
Disciplines such as Digital Signal Processing (DSP) and the study of
wavelets allow for much more accurate processing of signals than
analog systems were ever able to achieve.
Lastly, a sequence of digital numbers can also be stored more compactly
than an analog signal, e.i. MP3 devices in addition, supplementary data can be stored along with the samples for information such as digital watermarking for security or codes for error
checking or error correction.
6. Name three drawbacks of a digital system over an analog system.
Firstly, if the samples are taken too slowly, details of the analog input are missed.
Secondly, if the accuracy of the samples is not fine enough, the signal may not be precisely represented with the digital values.
Lastly, additional hardware is required to convert the signal from analog to digital.
7. True or False: Since non-periodic pulse trains do not have a
predictable format, there are no defining measurements of the
signal.
True, because it has no predictable format because, do not have a
characteristic pattern in their changes between logic 1 and logic 0.
8. If a computer runs at 12.8 GHz, what is the period of its clock
signal?
9. If the period of a periodic pulse train is 125 nanoseconds, what is
the signal's frequency?
10. If the period of a periodic pulse train is 50 microseconds, what
should the pulse width, tw, be to achieve a duty cycle of 15%?
-25%
11. True or False: A signal’s frequency can be calculated from its duty
cycle alone.
- True
