FX118

CML Semiconductor Products PRODUCT INFORMATION FX118 Features/Applications Frequency Inversion Scrambling Full-Duplex Operation High Baseband and Carrier www.DataSheet4U.com Rejection Audio Lowpass and Bandpass Filtering On-Chip Xtal Oscillator Stabilty Duplex Frequency Inverter for Cordless Telephones Publication D/118/3 July 1994 Low Power Requirement (3.0 Volt Minimum) Cordless Telephones Base and Handheld Applications Input Gain Adjustment Plastic DIL and S.O.I.C. Package Styles C1 AMP OUT LPF(1) LPF(1) OUT B MOD(1) IN BAL MOD (1) BPF(1) C1 IN C1 OUT +0.5dB INPUT AMP CHANNEL 1 (C1) -4.0dB +4.0dB V BIAS XTAL/CLOCK XTAL CLOCKS and LOGIC FILTER CLOCKS 111kHz CARRIER 3.3kHz V DD V BIAS V SS FX118 V BIAS INPUT AMP CHANNEL 2 (C2) -4.0dB C2 OUT C2 IN +0.5dB LPF(2) BAL MOD (2) +4.0dB BPF(2) C2 AMP OUT LPF(2) OUT B MOD(2) IN Fig.1 FX118 Duplex Frequency Inverter Brief Description The FX118 is a low-power, full-duplex frequency inverter available to provide voice privacy for cordless telephone systems by mixing the incoming audio with an internally produced carrier frequency (3.3kHz). This chip contains two completely separate audio channels (C1 and C2) each comprising a “componentadjustable” input amplifier, a 10th-order lowpass filter, a balanced modulator and a 14th-order bandpass filter output. The on-chip modulation process has the properties of high baseband and carrier frequency rejection which when combined with high-order output filtering, produces ...