Memo: Wavelet filter bank

The discrete wavelet transformation (DWT) on paper is realized in practice in the form of filter banks. A filter bank consists of low-pass and high-pass filters that can be represented as coefficients matrices. These matrices are derived from the impulse response analysis of the base filter functions in z-domain. To be qualified as a DWT filter… Continue reading Memo: Wavelet filter bank

Memo: Wavelets compression basics

Data compression is the representation or re-encoding of information from its complete, readily usable form, to a mere recipe. The recipe can then be transmitted compactly and reconstructed at the end-user using the building blocks at the end system. In the data compression scene, the two most prevalent players are the classic Fourier transformation (and… Continue reading Memo: Wavelets compression basics

Memo: Phase-locked loop

Phased-lock loop (PLL) synchronizes the frequency of output and input signals. The output signal is generated internally as part of the phase-lock loop; specifically from its variable-frequency oscillator (VFO). PLL applications PLLs are primarily used for clock synchronization within IC packages, encompassing the whole or parts of the IC's (signal processing) circuitry within its loop… Continue reading Memo: Phase-locked loop

Memo: Analog multiplier and voltage-controlled circuits

Analog multipliers are commonly available as integrated circuits (IC) and are rarely constructed from scratch due to their complexity. Multipliers commonly have 8 pinouts: X1, X2, Y1, Y2, W, Z, +VCC, -VCC. The common AD632 and MPY634 devices consist of one feedback line (W), two ground lines (X2, Y2), two supply lines (+VCC, -VCC) and one… Continue reading Memo: Analog multiplier and voltage-controlled circuits