Prev: How to detect signal from microwave sensor?
Next: STUPIDENT::Re: oulse code modulation question
From: Jerry Avins on 22 Jun 2010 23:37
On 6/21/2010 6:59 PM, bos1234 wrote:
>> On 06/21/2010 06:13 AM, bos1234 wrote:
>>>> On 06/20/2010 06:41 PM, bos1234 wrote:
>>>>> A continuous data signal is quantized and transmitted using a PCM
>>> system.
>>>>> If each data sample at the receiving end of the system must be known
> to
>>>>> within 0.5 percent of the peak-to-peak full-scale value, how many
>>> binary
>>>>> symbols must each transmitted digital word contain?
>>>>>
>>>>> I assumed that pk-pk of the signal is some constant A.
>>>>> So what is represented by Ax0.5%??
>>>>
>>>> Homework? What does your prof say? If you represent A with an N-bit
>>>> binary number that's all ones, then what's the value of 00 ... 01
> (i.e.
>>>> N-1 zeros and a 1 in the least significant place).
>>>>
>>>> --
>>>> Tim Wescott
>>>> Control system and signal processing consulting
>>>> www.wescottdesign.com
>>>>
>>> studying for exam. This is what the soln. says...
>>> q=2^n=A/del
>>> note:
>>> del --> delta --> the distance between a quantisation level.
>>>
>>> del/2< 0.5/100* A where A is the pk-pk value of the data signal.
>>>
>>> del< 0.01A
>>> de/A< 0.01
>>> A/del> 100 so q =128 and n=7
>>>
>>> But does this even answer the question when they ask "how many binary
>>> symbols must each transmitted digital word contain"
>>> Isn't binary symbol a 0 or 1?
>>
>> Isn't it? If it were, would you need to send 128 of them, or 7, or some
>> other number, to slice the pulse into 128 levels?
>>
>> --
>> Tim Wescott
>> Control system and signal processing consulting
>> www.wescottdesign.com
>
> what you mean??? So there are 128 levels and 7 bits/sample. I cannot
> extract any more information from the question other that this

Seven bits is 1 out of 128, or about 0.8%. How many bits do you need to
equal or exceed .5%?

Jerry
--
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������
First  |  Prev  | 
Pages: 1 2
Prev: How to detect signal from microwave sensor?
Next: STUPIDENT::Re: oulse code modulation question