Linearized 9-Bit Hybrid LBDD PWM Modulator for Digital Class-BD Amplifier

The paper presents an original architecture andimplementation of 9-bit Linearized Pulse Width Modulator(LPWM) for Class-BD amplifier, based on the hybrid methodusing STM32 microcontroller and Programmable Tapped DelayLine (PTDL). The analog input signals are converted into 12-bitPCM signals, then are directly transformed into 32-bit LBDDDPWM data of the pulse-edge locations within n-th period of theswitching frequency, next requantized to the 9-bit digitaloutputs, and finally converted into the two physical trains of 1-bitPWM signals, to control the output stage of the Class-BD audioamplifier. The hybrid 9-bit quantizer converts 6 MSB bits usingcounter method, based on the peripherals of STM32microcontroller, while the remaining 3 LSB bits - using a methodbased on the PTDL. In the paper extensive verification ofalgorithm and circuit operation as well as simulation inMATLAB and experimental results of the proposed 9-bit hybridLBDD DPWM circuit have been performed. It allows to attainSNR of 80 dB and THD about 0,3% within the audio baseband

Filterless, Digital Class-BD Audio Amplifiers with Constant Common Mode Output Voltage

This paper presents new and original architectures and implementations of two filterless, open-loop digital Class-BD audio amplifiers with constant common mode (CM) output voltage. The first, low-power amplifier consists of four ultrahigh-current EL7158 pin drivers, the OUT pins of which form the H bridge. The drivers are controlled from the extended LBDD PWM modulator and have appropriately set voltage levels on the VL and VH pins. The second proposed amplifier consists of two cooperating H-bridge power stages (HBS) implemented on complementary MOSFET pairs and powered by two different voltages. Both HBSs are driven by four EL7158 pin drivers having appropriately adjusted voltage levels on the VL and VH pins and controlled by an extended LBDD PWM modulator. The hybrid 9 bit DPWM modulator uses a linearized Class-BD double-sided modulation scheme with pre-compensation, enabling the most faithful emulation of natural NBDD PWM and, thus, providing attractive spectral characteristics at the DM output. Basic SPICE simulations and experimental results of the proposed digital Class-BD amplifiers were compared with the conventional digital Class-BD amplifiers. The elimination of CM signals significantly contributes to the reduction in electromagnetic interference (EMI), particularly those produced on the cables connecting the loudspeaker to the HBS terminal. Proposed Class-BD amplifiers with original and new topologies, due to their simple design and easy control (no galvanic isolation of control signals and no floating bias power supplies), which generate no CM voltage and feature excellent DM performance, similar to conventional Class-BD amplifiers, are very attractive solutions for filterless Class-BD amplifiers

Układ kompensujący odporność szeregową linii komutowanego toru opis patentowy nr 156964 /

Zgłoszono 23 czerwca 1988 r.Zgłoszenie ogłoszono 27 grudnia 1989 BUP 26/89.O udzieleniu patentu ogłoszono 30 kwietnia 1992 WUP 04/92.Nr zgłosz. P 273320.Tyt. z ekranu tyt.Dostępny także w wersji drukowanej.Tryb dostępu: Internet

Urządzenie dwutonowego wywołania abonenta w elektronicznym zespołowym aparacie telefonicznym opis patentowy nr 118543 /

Zgłoszono 13 maja 1978 r.Zgłoszenie ogłoszono 11 lutego 1980 r.Opublikowano 15 sierpnia 1983 r.Nr zgłosz. P 206761.Tyt. z ekranu tyt.Dostępny także w wersji drukowanej.Tryb dostępu: Internet

Układ sterująco-komutujący telefonicznych aparatów zespołowych opis patentowy nr 127075 /

Zgłoszono 12 września 1979 r.Zgłoszenie ogłoszono 13 marca 1981 r.Opublikowano 30 kwietnia 1985 r.Nr zgłosz. P 218289.Tyt. z ekranu tyt.Dostępny także w wersji drukowanej.Tryb dostępu: Internet

Układ zabezpieczenia systemu zespołowych aparatów telefonicznych opis patentowy nr 120548 /

Tyt. z ekranu tyt.Zgłoszono 20 września 1978 r.Numer zgłosz. P.209732.Zgłoszenie ogłoszono 19 maja 1980 r.Opublikowano 31 stycznia 1984 r.Dostępny także w wersji drukowanej.Tryb dostępu: Internet

Facilitated percutaneous coronary intervention in patients with acute myocardial infarction transferred from remote hospitals

Two hundred patients with acute myocardial infarction admitted to hospitals. remote from a interventional center (transfer time >90 minutes) received IV bolus doses of heparin, half-dose alteplase, and abciximab, and were immediately transferred to the interventional center, with continued alteplase and abciximab infusions. Transfer was safe with no deaths. Seventy-one percent of the patients presented with TIMI grade 3 flow in the infarct-related artery at the diagnostic angiography, whereas percutaneous intervention facilitated by this lytic regimen resulted in a final TIMI 3 flow in 93% of patients and low mortality at 30 days (3.5%); however, there were frequent bleeding complications