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DS8913 Datasheet Sound Up-conversion Frequency Synthesizer

Manufacturer: National Semiconductor (now Texas Instruments)

Overview: DS8911 DS8913 AM FM TV Sound Up-Conversion Frequency Synthesizer April 1990 DS8911 DS8913 AM FM TV Sound Up-Conversion Frequency.

General Description

The DS8911 is a digital Phase-Locked Loop (PLL) frequency synthesizer intended for use as a Local Oscillator (LO) in electronically tuned radios The device is used in conjunction 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 spurious responses occur far beyond the range of frequencies to be tuned Sufficient selectivity and second IF image protection is provided by a crystal filter at the output of the first mixer A significant cost savings can be realized utilizing this upconversion 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 alignment 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 conversion radios is reduced to a 10% tuning range 9 94 MHz to 11 02 MHz) Up-conversion AM tuning is acplished by first dividing the VCO signal down by a modulus 10 to obtain the LO signal This LO in turn is mixed on chip with the RF signal to obtain a first IF at the MIXER output pins This first IF after crystal filtering is mixed (external

Key Features

  • Y Y Y Y Y Y Direct synthesis of LW MW SW FM and WB frequencies Serial data entry for simplified processor control 10 12 5 25 and 100 kHz reference frequencies 8 possible tuning resolutions (see Table II) An op amp with high impedance inputs for loop filtering Programmable mixer with high dynamic range TRI-STATE is a registered trademark of National Semiconductor Corporation.

More Datasheets from National Semiconductor (now Texas Instruments)

Part Number Description
DS8911 Sound Up-Conversion Frequency Synthesizer
DS8907 Phase-Locked Loop Frequency Synthesizer
DS8921 Differential Line Driver and Receiver Pair
DS8921A Differential Line Driver and Receiver Pair
DS8921AT Differential Line Driver and Receiver Pair
DS8922 TRI-STATE RS-422 Dual Differential Line Driver and Receiver Pairs
DS8922A RS-422 Dual Differential Line Driver and Receiver Pairs
DS8923A RS-422 Dual Differential Line Driver and Receiver Pairs
DS8925 LocalTalk Dual Driver/Triple Receiver
DS8935 LocalTalk Dual Driver/Triple Receiver

DS8913 Distributor