Sound Up-conversion Frequency Synthesizer - National Semiconductor

The DS8911 is a digital Phase-Locked Loop (PLL) frequen- cy synthesizer DS8911 DS8913 intended for use as a Local Oscillator (LO) in electronically tuned Radios The device is used in conjunc- tion with a serial data controller, a loop Filter some varactor Diodes and several passive elements to provide the local Oscillator function for both AM and FM tuning. The conventional superheterodyne AM receiver utilizes a low IF or down conversion tuning approach whereby the IF is chosen to be below the frequencies to be received. The DS8911 PLL on the other hand, utilizes an up-conversion technique in the AM mode whereby the first IF frequency is chosen to be well above the RF frequency range to be tuned. This approach eliminates the need for tuned circuits in the AM frontend since the image, half IF, and other spuri- ous responses occur far beyond the range of frequencies to be tuned. Sufficient selectivity and second IF image protec- tion is provided by a crystal Filter at the output of the first mixer. A significant cost savings CAN be realized utilizing this up- conversion approach to tuning. Removal of the AM tuned circuits eliminates the cost of expensive matched varactor Diodes and reduces the amount of labor required for align- ment down from 6 adjustments to 2. Additional cost savings are realized because up-conversion enables both the AM and FM bands to be tuned using a single Voltage Controlled Oscillator (VCO) operating between 98 and 120 MHz. (The 2 to 1 LO tuning range found in conventional AM down con- version Radios is reduced to a 10% tuning range; 9.94 MHz to 11.02 MHz). By National Semiconductor Corporation
DS8911 's PackagesDS8911 's pdf datasheet

DS8911 Pinout, Pinouts
DS8911 pinout,Pin out
This is one package pinout of DS8911,If you need more pinouts please download DS8911's pdf datasheet.

DS8911 Application circuits
DS8911 circuits
This is one application circuit of DS8911,If you need more circuits,please download DS8911's pdf datasheet.

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