FX118 Datasheet | Consumer Microcircuits Limited

Features /Applications Frequency Inversion Scrambling Full-Duplex Operation High Baseband and Carrier .. 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 +0.5d B INPUT AMP CHANNEL 1 (C1) -4.0d B +4.0d B V BIAS XTAL/CLOCK XTAL CLOCKS and LOGIC FILTER CLOCKS 111k Hz CARRIER 3.3k Hz V DD V BIAS V SS V BIAS INPUT AMP CHANNEL 2 (C2) -4.0d B C2 OUT C2 IN +0.5d B LPF(2) BAL MOD (2) +4.0d B 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 ining audio with an internally produced carrier frequency (3.3k Hz). This chip contains two pletely separate audio channels (C1 and C2) each prising a “ponentadjustable” 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 bined with high-order output filtering, produces a high-quality recovered voiceband audio. The frequency stability of the FX118 is achieved by an on-chip oscillator employing an external 4.433619MHz Xtal or clock input to produce the mon carrier frequency and the sampling clocks for the switched capacitor low and bandpass filters. This microcircuit has a low power requirement of 3.0 volts (min.) and is encapsulated in either 16-pin DIL or small outline SMD (S.O.I.C.) plastic packages both of which are of a physical size suitable for either base or handset type telephone instruments as well as batteryportable and mobile...