<Li> Oversampling DACs or interpolating DACs such as the delta - sigma DAC, use a pulse density conversion technique . The oversampling technique allows for the use of a lower resolution DAC internally . A simple 1 - bit DAC is often chosen because the oversampled result is inherently linear . The DAC is driven with a pulse - density modulated signal, created with the use of a low - pass filter, step nonlinearity (the actual 1 - bit DAC), and negative feedback loop, in a technique called delta - sigma modulation . This results in an effective high - pass filter acting on the quantization (signal processing) noise, thus steering this noise out of the low frequencies of interest into the megahertz frequencies of little interest, which is called noise shaping . The quantization noise at these high frequencies is removed or greatly attenuated by use of an analog low - pass filter at the output (sometimes a simple RC low - pass circuit is sufficient). Most very high resolution DACs (greater than 16 bits) are of this type due to its high linearity and low cost . Higher oversampling rates can relax the specifications of the output low - pass filter and enable further suppression of quantization noise . Speeds of greater than 100 thousand samples per second (for example, 192 kHz) and resolutions of 24 bits are attainable with delta - sigma DACs . A short comparison with pulse - width modulation shows that a 1 - bit DAC with a simple first - order integrator would have to run at 3 THz (which is physically unrealizable) to achieve 24 meaningful bits of resolution, requiring a higher - order low - pass filter in the noise - shaping loop . A single integrator is a low - pass filter with a frequency response inversely proportional to frequency and using one such integrator in the noise - shaping loop is a first order delta - sigma modulator . Multiple higher order topologies (such as MASH) are used to achieve higher degrees of noise - shaping with a stable topology . </Li> <Li> The binary - weighted DAC, which contains individual electrical components for each bit of the DAC connected to a summing point . These precise voltages or currents sum to the correct output value . This is one of the fastest conversion methods but suffers from poor accuracy because of the high precision required for each individual voltage or current . Such high - precision components are expensive, so this type of converter is usually limited to 8 - bit resolution or less . <Ul> <Li> Switched resistor DAC contains a parallel resistor network . Individual resistors are enabled or bypassed in the network based on the digital input . </Li> <Li> Switched current source DAC, from which different current sources are selected based on the digital input . </Li> <Li> Switched capacitor DAC contains a parallel capacitor network . Individual capacitors are connected or disconnected with switches based on the input . </Li> </Ul> </Li> <Ul> <Li> Switched resistor DAC contains a parallel resistor network . Individual resistors are enabled or bypassed in the network based on the digital input . </Li> <Li> Switched current source DAC, from which different current sources are selected based on the digital input . </Li> <Li> Switched capacitor DAC contains a parallel capacitor network . Individual capacitors are connected or disconnected with switches based on the input . </Li> </Ul> <Li> Switched resistor DAC contains a parallel resistor network . Individual resistors are enabled or bypassed in the network based on the digital input . </Li>

Which device converts analog signals to digital signals and vice versa