DIGITAL - COUNTER

On the rising edge of the clock pulse, D is copied to Q.
Since NOT Q is connected to D, the data is inverted on each rising edge.
This has the effect of dividing the frequency by two.

• The D Type Flip Flop is used in Binary Counters.
• Here is the circuit for a one bit counter.
• This can also be used as a frequency divider. It divides the frequency by two.
• The UP in Up Counter is because the counter counts normally with increasing numbers like 0, 1, 2, 3 etc.
• The output of this circuit is high for 50% of the time and low for 50% of the time.
• This is a 1:1 mark space ratio.
• This is true whatever the mark space ratio of the clock pulses.

AS A2

 _b

Three Bit Binary Up Counter

This divides the frequency by 8 (or by two three times).

On the rising edge of the clock pulse the counter output increases by one.

The output from the left flip-flop is worth one (least significant bit LSB).
The output from the middle flip-flop is worth two.
The output from the right flip-flop is worth 4 (most significant bit MSB).

Here is a timing diagram for the three bit counter.

 _c

Modulo N Up Counter

This is a counter that resets at a chosen number. For example a two digit decimal counter, left to its own devices will count from 00 to 99. This is not much use for a clock unless you have 100 second minutes. To fix the problem, the counter must go from 00 to 59. This is achieved by detecting a 6 in the left hand digit and using it to reset the counter to zero. This would be a Modulo 6 Counter or 60 if you included both digits.

 _d

Modulo 6 Counter - Counts from 0 to 5

The circuit above detects a six or 0110 in binary. You could use the fool proof circuit but in fact the simpler circuit works too because the 0110 pattern only occurs once between 0 and 9 in decimal numbers. The output is used to reset the counter.

Frequency Division and Counting

Frequency Division

In the tutorials, we saw how D-type Flip-Flop´s work and how they can be connected together to form a data latch . Another useful feature of the D-type Flip-Flop is as a binary divider, for Frequency Division or as a “divide-by-2″ counter. 

Divide by 2 counter

It can be seen from the frequency waveforms above, that by “feeding back” the output from Q to the input terminal D, the output pulses at Q have a frequency that are exactly one half ( f ÷ 2 ) that of the input clock frequency. In other words the circuit produces Frequency Division as it now divides the input frequency by a factor of two (an octave).This then produces a type of counter called a “ripple counter” and in ripple counters, the clock pulse triggers the first flip-flop whose output triggers the second flip-flop, which in turn triggers the third flip-flop and so on through the chain producing a ripple effect (hence their name) of the timing signal as it passes through the chain.

Frequency Division. The Q output of the second flip-flop is one-fourth the frequency of the original clock input.

 Frequency Division

To enable local scheduling with channel state information for wireless multi-hop networks with orthogonal frequency division multiplexing (

Frequency Division Summary

For frequency division, toggle mode flip-flops are used in a chain as a divide by two counter. 

The final output clock signal will have a frequency value equal to the input clock frequency divided by the MOD number of the counter. Such circuits are known as “divide-by-n” counters. Counters can be formed by connecting individual flip-flops together and are classified according to the way they are clocked.

Frequency Counting

CB FREQUENCY COUNTER

The basic idea of making a frequency counter is to count the number of cycles of the input in one second. We can keep one counter that keeps counting the rising/falling edges of the input signal. Then we can read the value of this counter once in a second and then clear it. The value we read from the counter is nothin but the frequency of the input signal.

The reciprocal method seems to also be impmemented to cheap frequency counter because of price of microcontrollers falls.

The hi-tech frequency counter board

Frequency counter counting

This is one of the frequency measureing methods that was thought out to make up the defect of direct counting method, and it is prevailing now. This method measures the period (T) of the input signal instead of number of cycles, and calcurate its frequency in the formula f = 1 / T with a microprocessor. Its frequency resolution depends on only time resolution independent of the input frequency.

Ingin Cepat Lulus Kuliah? Ini Caranya!


Siapa sih yang tidak mau cepat lulus kuliah? Pastinya semua mahasiswa ingin cepat lulus kuliah dan ingin cepat mencari kerja yang layak sesuai dengan jurusan kuliah yang di tempuh. Namun bagaimana untuk mahasiswa yang bandel jarang masuk kuliah, namun ingin cepat lulus?. Disini saya mempunyai tipsrahasia cepat lulus kuliah bagi anda para mahasiswa yang jarang masuk kuliah.


Cara Cepat Lulus Kuliah Bagi Mahasiswa Bandel

1. Punya Banyak Teman Di Kampus

Carilah teman sebanyak mungkin di kampus anda, paling tidak anda mempunyai banyak teman cewek yang akrab dengan anda. Disini anda dapat memanfaatkannya sebagai sumber informasi tugas kampus atau ikut nebeng mengerjakan tugas-tugas di kampus. hehehehe. :)

2. Selalu Ngumpulin Tugas Dan Ikut Ujian "UTS dan UAS".

Jangan sampai anda tidak mengumpulkan tugas yang dosen perintahkan, karena 30% nilai di ambil dari tugas setiap mata kuliah, tergantung dosen menegoisasikannya bagaimana. Jika anda jarang masuk, kembali ke tips no. 1, tanya teman anda atau nebeng buat ngerjain sekaligus ngumpulin tugas.

Harus wajib mengikuti Ujian " UTS dan UAS , anda harus hadir untuk mengerjakan ujian di setiap semesternya. Belajar sedikit atau siapkan contekan "memang sih gak bagus, namun nyontek sedikit gak papakan? hehehehe ^_^. Nilai Ujian ini berpengaruh besar pada nilai akhir per-matakuliah, yaitu 60% dari keseluruhan nilai per-matakuliah.

Berikut ini adalah rincian nilai kuliah , " Setiap kampus berbeda-beda loh yua "

10% : Kehadiran "absensi"
30% : Tugas Setiap mata kuliah
60% : Ujian setiap mata kuliah

Misalkan saja anda tidak pernah hadir kuliah atau bolong-bolong , namun selalu mengumpulkan tugas dan mengikuti ujian , otomatis nilai anda setiap mata kuliah yaitu "B". " anggap saja begitu , hehehe. "

3. Banyak amal dan Ibadah 

Banyak-banyak beramal, walaupun Tuhan bukan tempat mengemis nilai , paling tidak Tuhan akan meringankan beban mu jika kamu tulus dan iklas berbuat kebaikan.

Nah itulah tadi rahasia cepat lulus kuliah dengan nilai baik untuk mahasiswa yang bandel , males masuk kuliah. Sekian dulu tips dari saya. Sambut seruan saya ! Hidup Mahasiswa !!!