公开(公告)号：US3786350A

公开(公告)日：1974-01-15

申请号：US3786350D

申请日：1972-08-21

Applicant: WESTON INSTRUMENTS INC

Inventor： MUNT I

IPC: G01D3/02 ,  G01R15/00 ,  G01R27/02 ,  H03M1/00

CPC classification number: G01R27/02 ,  H03M1/52

Abstract: A digital ohmmeter having a differential amplifier with a capacitor connected between the output and the inverting input to form an integrator. A source of DC voltage is connected to a series circuit including the unknown resistor and to a switch which selectively connects the source to a second series circuit, an intermediate point of which is connected to the inverting terminal of the amplifier. The unknown resistor is connected to the noninverting input. The output of the amplifier is connected to logic circuit and counting means of the type used in dual slope integrating digital voltmeters, and others such as voltageto-frequency converters, with the logic means having an output to control the switch means. The switch is open for a fixed interval and closed for a variable interval, which variable interval is counted as a measure of the input resistance. In this embodiment, the two series resistance circuits form a bridge when the switch is closed. In a second embodiment an additional switch connects the second series circuit to ground when it is disconnected from the source. In either embodiment the resistance value is linearly proportional to the length of the variable interval of time multiplied by a constant, the constant being determined by the fixed resistors in the two series circuits.

Abstract translation: 一种具有差分放大器的数字欧姆表，其中电容器连接在输出和反相输入端之间以形成积分器。 直流电压源连接到包括未知电阻的串联电路和连接到第二串联电路的开关，该第二串联电路的中间点连接到放大器的反相端。 未知电阻连接到同相输入。 放大器的输出连接到逻辑电路和用于双斜率积分数字电压表中的类型的计数装置，以及其它诸如电压 - 频率转换器的逻辑装置具有用于控制开关装置的输出。 开关打开一个固定的间隔，并关闭一个可变间隔，该可变间隔被计为输入电阻的量度。 在本实施例中，当开关闭合时，两个串联电阻电路形成桥。 在第二实施例中，附加开关在与源极断开时将第二串联电路连接到地。 在任一实施例中，电阻值与可变时间间隔的长度乘以常数成线性比例，该常数由两个串联电路中的固定电阻器确定。

公开(公告)号：US3743939A

公开(公告)日：1973-07-03

申请号：US3743939D

申请日：1972-05-01

Applicant: WESTON INSTRUMENTS INC

Inventor： MUNT I

IPC: G01R15/12 ,  G01R19/255 ,  G01R35/00 ,  H03M1/00

CPC classification number: G01R19/255 ,  G01R15/125 ,  G01R35/00 ,  H03M1/52

Abstract: An apparatus for use with a multimeter of the digital display type wherein battery voltage and the various logic components of the meter can be tested. In a meter of the type having a dual slope integrating converter ther is provided a switch for connecting the battery terminal voltage to the input of the integrator and for utilizing the reference current switching interval to establish a test portion of the measurement cycle. The reference current interval establishes a signal for a test logic package which produces signals to transfer count information directly to the display element while the count is being accumulated; to activate display complement circuitry to illuminate all segments of the display means; and to alter the scan rate illuminating those display to brighten the display during test, keeping the duty cycle thereof at a minimum level for conserving battery voltage when not on test. Using the reference voltage portion of the test cycle, the display is caused to flicker, advantageously at a one-quarter cycle rate, and all segments are caused to be illuminated during some portion of the cycle, thereby providing a simple visual check of the various logic components of the system, all display elements, and a relatively static display of the battery voltage with a single switch position. Very little additional circuitry is needed to perform all of these functions.

Abstract translation: 一种用于数字显示类型的万用表的装置，其中可以测试电池电压和仪表的各种逻辑组件。 在具有双斜率积分转换器的类型的仪表中，提供了用于将电池端子电压连接到积分器的输入并且利用参考电流切换间隔来建立测量周期的测试部分的开关。 参考电流间隔建立用于测试逻辑封装的信号，其产生信号以在计数被累积时将计数信息直接传送到显示元件; 激活显示器补码电路以照亮显示装置的所有段; 并且在测试期间改变照亮这些显示器以使显示器变亮的扫描速率，将其占空比保持在最小水平，以便在不测试时节省电池电压。 使用测试周期的参考电压部分，使显示器有利地以四分之一周期的速率闪烁，并且使所有段在周期的某些部分被照亮，从而提供各种各样的视觉检查 系统的逻辑组件，所有显示元件以及具有单个开关位置的电池电压的相对静态显示。 需要很少的附加电路来执行所有这些功能。

公开(公告)号：US3749896A

公开(公告)日：1973-07-31

申请号：US3749896D

申请日：1971-09-24

Applicant: WESTON INSTRUMENTS INC

Inventor： MUNT I

IPC: G06F3/147 ,  G06F3/14 ,  G09G3/04 ,  H03K21/08

CPC classification number: H03K21/08 ,  G06F3/1407 ,  G09G3/04

Abstract: An apparatus for editing information to be presented to a display to remove unwanted leading zeroes. The apparatus includes logic circuit means for accepting information about the digit and the preceding digit and then deciding whether or not to blank the digit. If the blank decision is made the logic circuit provides an inhibit signal. The information provided to the logic includes a signal indicating that the digit be examined is or is not a zero; a signal indicating whether or not the preceding digit was blanked or that this is the first digit; and a signal indicating whether the digit under examination is immediately preceded by a decimal point. The digits examined in an ordered sequence beginning with the highest ordered digit and proceeding toward the lower, each digit being examined in a well-defined time interval and either blanked or not blanked before the next digit is examined.

Abstract translation: 用于编辑要呈现给显示器以消除不期望的前导零的信息的装置。 该装置包括用于接受关于数字和前一数字的信息的逻辑电路装置，然后判定是否空白该数字。 如果空白确定，则逻辑电路提供禁止信号。 提供给逻辑的信息包括指示被检查的数字是或不是零的信号; 指示前一个数字是否被消隐的信号或者这是第一个数字; 并且指示正在检查的数字是否紧接在小数点之前的信号。 以有序序列开头的数字以最高有序数字开头，并朝着较低的数字进行检查，每个数字以明确的时间间隔进行检查，并在检查下一个数字之前消隐或不被消隐。