To study the working principle pesintesa frequency (frequency synthesizer) with PLL, we can learn to block in the block of parts of the PLL. One of the most popular programmable divider IC is TC9122. IC is known as one of the PLL components in HT 2m Transceiver: ICOM IC-2N.
In general, this chip other than as a programmable divider in the PLL, can also be used as a frequency divider in other applications.Skema TC9122 PROGRAMMABLE DIVIDER
Here are the features possessed IC TC9122:
- F max = 15 MHz, if you are using a PLL in the FM band, of course you should add the prescaler (about prescaler wait in another posting aja ya ... ..)
- Frequency distribution using the principle of BCD (binary coded decimal), in contrast with the principles of the IC MC145151 (see previous posting).
- The performance of frequency division by the number 8-3999.
- Built-in amplifier with self-bias type, which can be operated with a small signal with a coupling capacitor.
- Supply Voltage 4.5 to 8.5 Volt.
Notice the pins explanation for this chip:
No Pin. 2: Pin, INPUT terminal, can be derived from the VCO or Prescaler
No Pin. 3-16: a program division (N) with the principle of the BCD, the value N = 8-3999
No Pin. 17: Pout, OUTPUT terminal (1 / N) from this pin to the next phase
No Pin. 1: VDD, the positive power supply
No Pin. 18: GND, ground.
Next we consider an internal block diagram of this chip:
A0, B0, C0, D0 indicates UNITS
A1, B1, C1, D1 showed dozens
A2, B2, C2, D2 showed hundreds
A3, B3, showed THOUSANDS
Suppose that we program the PLL frequency calculations on a N = 3567
Figures unit = 7, mean A0, B0, C0, D0 = 1, 1, 1, 0
Figures tens = 6, mean A1, B1, C1, D1 = 0, 1, 1, 0
Figures hundreds = 5, means A2, B2, C2, D2 = 1, 0, 1, 0
Figures thousands = 3, means the A3, B3 = 1, 1
That bit of information about IC TC 9122, probably in the next posting we try to review TC5081 and TC 5082. keep the spirit pray for ya ....