Replacing the AD7768: GX7768 8/4-Channel 24-Bit ADC for Audio Test and Measurement

Audio test and measurement is one of the technical steps in the R&D and production quality inspection of audio equipment, covering a variety of applications such as amplifier THD+N testing, loudspeaker frequency response measurement, microphone arrays, acoustic spectrum analysis, and performance evaluation of electroacoustic transducers. Such testing requires sufficient dynamic range to cover the measurement span from weak noise floors to full-scale signals; low total harmonic distortion to accurately characterize the nonlinearity of the device under test; and multi-channel synchronous sampling capability to support phase consistency in array-based systems.

The GX7768 8/4-channel 24-bit analog-to-digital converter is designed specifically for high-precision measurement. Each channel integrates a Σ-Δ modulator and a digital filter, ensuring high accuracy in data acquisition. This highly integrated design not only simplifies the system architecture but also improves overall performance. The device supports precise synchronous sampling across channels, which is critical for handling both AC and DC signals, effectively eliminating phase errors and ensuring the accuracy of measurement results.

The GX7768 employs oversampling and noise-shaping techniques to accurately capture small signals over a wide dynamic range, achieving extremely high resolution and precision, making it particularly suitable for high-precision measurement and sensor signal processing applications. The product features are as follows:

• Precision AC and DC performance

• 8/4-channel synchronous sampling, with a maximum output rate of 256 kSPS per channel

• Dynamic range: 106 dB

• Maximum input bandwidth: 110.8 kHz (-3 dB bandwidth)

• Selectable power consumption, speed, and input bandwidth (BW) modes

Fast: highest speed; 110.8 kHz bandwidth, 81.25 mW per channel

Medium speed: half speed, 55.4 kHz bandwidth, 39.375 mW per channel

Low power: lowest power consumption, 13.8 kHz bandwidth, 26.55 mW per channel

• Independent digital filter per channel

• Programmable input bandwidth/sampling rate

• Data interface supports cyclic redundancy check (CRC) error detection

• Linear-phase digital filter