公开(公告)号：US4061886A

公开(公告)日：1977-12-06

申请号：US617955

申请日：1975-09-29

Applicant: Michael James Callahan, Jr. ,  Gordon Bates Hoffman

Inventor： Michael James Callahan, Jr. ,  Gordon Bates Hoffman

IPC: H03B11/00 ,  H03B28/00 ,  H03L7/18 ,  H04L27/26 ,  H04M1/50 ,  H04M1/26

CPC classification number: H04M1/505

Abstract: A dual-tone multiple frequency signal generator is provided for use with telecommunications systems, data transfer systems and other applications. The tone encoding system utilizes MOS/LSI integrated circuitry on a single chip powered directly by telephone line voltages. An electronic keyboard circuit provides synchronized pulses to decode single-pole, single-throw keyboard switches by row and column. A crystal-controlled oscillator generates a reference frequency which is divided according to the row and column of an activated keyboard switch to obtain two pulse signals having frequencies representative of the activated switch. The outputs of the divider circuitry are fed to programmed logic array which generates two digitally coded signals each representing a sinusoidal waveform. A digital-to-analog ladder network converts the digitally coded signals to continuous sine waves, and an operational amplifier combines the sinusoidal waveforms to provide a dual-tone output. The integrated circuitry also utilizes electronic switches for the common functions of tone transmission, including applying power to the oscillator, disconnecting the audio transmitter and attenuating the input to the receiver. Complementary-symmetry, metal-oxide semi-conductor elements implement the circuitry design with bi-polar transistors on the same chip performing some of the common function switching.

Abstract translation: 提供双音多频信号发生器用于电信系统，数据传输系统和其他应用。 音调编码系统在直接由电话线电压供电的单个芯片上使用MOS / LSI集成电路。 电子键盘电路提供同步脉冲，通过行和列解码单刀单掷键盘开关。 晶体振荡器产生根据激活的键盘开关的行和列分割的参考频率，以获得具有表示激活的开关的频率的两个脉冲信号。 分频器电路的输出被馈送到编程逻辑阵列，其产生每个表示正弦波形的两个数字编码信号。 数模转换梯形网将数字编码信号转换为连续正弦波，运算放大器组合正弦波形以提供双音输出。 集成电路还利用电子开关用于音调传输的共同功能，包括向振荡器施加电力，断开音频发射器并衰减到接收机的输入。 互补对称，金属氧化物半导体元件在同一芯片上实现具有双极晶体管的电路设计，执行一些通用功能切换。

公开(公告)号：US08248747B2

公开(公告)日：2012-08-21

申请号：US12627729

申请日：2009-11-30

Applicant: Michael James Callahan, Jr.

Inventor： Michael James Callahan, Jr.

IPC: H02H3/08 ,  H02H9/02

CPC classification number: G01R19/16571 ,  H03K17/0826

Abstract: A bi-directional protection circuit employs a single comparator for detecting fault conditions. Diodes are coupled between a detection node and voltage dividers setting references for inverting and non-inverting comparator inputs, each diode forward biased during one of the positive and negative halves of the alternating current input signal cycle and coupling the detection node to a respective one of the inverting and non-inverting comparator inputs, and reverse biased during the other of the positive and negative halves and decoupling the detection node from the other of the inverting and non-inverting comparator inputs. Upon an overcurrent condition during the positive half, a voltage at the inverting comparator input is drawn above the reference voltage at the non-inverting input. Upon an overcurrent condition during the negative half, a voltage at the non-inverting comparator input is drawn below the reference voltage at the inverting input.

Abstract translation: 双向保护电路采用单个比较器来检测故障状况。 二极管耦合在检测节点和分压器之间，用于设置反相和非反相比较器输入的参考值，每个二极管在交流输入信号周期的正半周和负半周期期间正向偏置，并将检测节点耦合到 反相和非反相比较器输入，并在正半周和负半周中的另一个反向偏置，并将检测节点与反相和非反相比较器输入中的另一个去耦。 在正半周期的过电流条件下，反相比较器输入端的电压在非反相输入端上被吸引到基准电压之上。 在负半周期的过电流条件下，非反相比较器输入端的电压被拉低到反相输入端的参考电压以下。

公开(公告)号：US6043687A

公开(公告)日：2000-03-28

申请号：US124350

申请日：1998-07-29

Applicant: Michael James Callahan, Jr.

Inventor： Michael James Callahan, Jr.

IPC: H01L21/761 ,  H01L27/08 ,  H02P6/06

CPC classification number: H01L21/761 ,  H01L27/0802

Abstract: A precision analog circuit ensures precision matching between two or more resistive elements. In order that the two or more resistive elements are truly matched, a first electrical value, such as V.sub.DS, of the two or more resistive elements are equal and a second electrical value, such as V.sub.GS, of the two or more resistive elements are equal so that a ratio of the first resistive element to the second resistive element is a predetermined value regardless of the voltage coefficients of the resistive elements.

Abstract translation: 精密模拟电路确保两个或多个电阻元件之间的精度匹配。 为了使两个或更多个电阻元件真正匹配，两个或更多个电阻元件的第一电值（例如VDS）相等，并且两个或更多个电阻元件的第二电值（诸如VGS）相等 使得第一电阻元件与第二电阻元件的比率是与电阻元件的电压系数无关的预定值。