Abstract: An instantaneous bit-error-rate meter provides an instantaneous, real-time eading of bit-error-rate for digital communications data. Bit-error pulses are input into the meter and are first filtered in a buffer stage to provide input impedance matching and desensitization to pulse variations in amplitude, rise-time and pulse-width. The bit-error pulses are transformed into trigger signals for a timing pulse generator. The timing pulse generator generates timing pulses for each transformed bit-error pulse, and is calibrated to generate timing pulses having a preselected pulse width corresponding to the baud rate of the communications data. An integrator generates a voltage from the timing pulses that is representative of the bit-error-rate as a function of the data transmission rate. The integrated voltage is then displayed on a meter to indicate the bit-error-rate.

Abstract: The invented device provides automatic gain control (AGC) of incoming sigs over a large dynamic range of input levels with a constant rise time. The constant rise AGC device includes a primary AGC loop for receiving the incoming or input signal and splitting the input signal to input and output components of the primary AGC loop. The input signal to the input component is processed within the primary AGC loop to control the gain of the input signal at the output component of the primary AGC loop. The primary AGC loop has a slow detector. A secondary AGC loop is provided within the primary AGC loop, and this secondary AGC loop includes the aforementioned input component and has its output connected to the slow detector. The secondary AGC loop has a fast detector for preventing self-imposed saturation.

Abstract: A signal amplitude distribution analyzer measures the amplitude probability density function of electrical signals, and in particular, the amplitude probability distribution of noise signals. Such measurements may be used to determine the "Gaussianicity" of noise signals, that is, a measurement of how closely the amplitude distribution of noise signals corresponds to theoretical values derived from the Gaussian probability distribution density function. This theoretical density function represents the relative percentage of time that a noise signal is at a given amplitude. The invention gives an approximation of this function by measuring the amount of time a noise signal is between a window of two adjustable voltage levels. This is accomplished by producing an output voltage proportional to the amount of time a noise signal amplitude falls within the window of values defined by the two adjustable voltage levels.