## Washington Township Declares State of Emergency

As a public service, we are re-posting the local declaration here.

PROCLAMATION OF STATE OF EMERGENCY
TO ALL CITIZENS AND PERSONS WITHIN THE TOWNSHIP OF WASHINGTON AND TO ALL DEPARTMENTS, DIVISIONS AND BUREAUS OF THE MUNICIPAL GOVERNMENT OF THE TOWNSHIP OF WASHINGTON:

WHEREAS, pursuant to the powers vested in me by Chapter 251 of the laws of 1942, as amended and supplemented, N.J.S.A. App. A:9-30 et. seq.; N.J.S.A. 40:48-1 (6), and ordinances enacted pursuant thereto; N.J.S.A. 2C:33-1 et. seq., Executive Order 103 and by ordinances adopted by the Township of Washington I have declared that a STATE OF EMERGENCY exists within the Township of Washington; and

WHEREAS, the aforesaid laws authorize the promulgation of such orders, rules, and regulations as are necessary to meet the various problems which have or may be presented by such an emergency; and

WHEREAS, by reason of the rapidly evolving outbreak of the novel coronavirus, COVID-19, the need for government operations to address staffing capabilities to ensure essential operational needs are met in order to mitigate factors which may further adversely affect the health, safety, and welfare of the people of the Township of Washington and exacerbate and worsen existing conditions; and

WHEREAS, pursuant to N.J.S.A App. A:9-33.1, entitled “Emergency Powers of Government,” a disaster is defined as an unusual incident resulting from natural or unnatural causes which endangers the health or safety of residents; and

WHEREAS, it has been determined that in the event these areas of the Township of Washington should be declared disaster areas, and further that certain measures must be taken to ensure that the authorities will be unhampered in their efforts to maintain law and order as well as an orderly flow of traffic and further in order to protect the persons and property of the residents affected by the conditions and finally that governmental operations including but not limited to the conduct of public meetings shall be substantially altered; and

WHEREAS, all lands within the boundaries of the Township of Washington, as a result of the outbreak of the novel coronavirus, are hereby designated as disaster areas, in accordance with the “Emergency Powers of Government.”

NOW, THEREFORE, IN ACCORDANCE WITH the aforesaid laws, we do hereby promulgate and declare the following regulations shall be in addition to all other laws of the State of New Jersey and the Township of Washington.

/signed/

Matt Lopez, OEM Coordinator
Township of Washington

Matthew T. Murello, Mayor
Township of Washington

US and Canadian broadcast experts met in Toronto this month, at the Barrett Centre for Technology Innovation, to discuss how the new ATSC-3 Broadcast standard provides new opportunities for mass distribution of content, information, and data.  Among the participants was AGC Systems’ Aldo Cugnini, who met with Humber College research staff, who are hoping to create and lead the way for Canada’s first “ATSC Living Lab.”

## Happy Π Day

Math can be truly awe-inspiring, as in this example of the unexpected places that π can show up. The proof is nothing short of elegant – be sure to watch parts 2 and 3.  Astonishing!

–agc

## There’s No Such Thing as RMS Power!

This is one of my engineering pet peeves — I keep running into students and (false) advertisements that describe a power output in “RMS watts.”  The fact is, such a construct, while mathematically possible, has no meaning or relevance in engineering.  Power is measured in watts, and while the concepts of average and peak watts is tenable, “RMS power” is a fallacy.  Here’s why.

The power dissipated by a resistive load is equal to the square of the voltage across the load, divided by the resistance of the load.  Mathematically, this is expressed as [Eq.1]:

$$\large P=\frac{V^{2}}{R}$$

where P is the power in watts, V is the voltage in volts, and R is the resistance in ohms.  When we have a DC signal, calculating the power in the load is straightforward.  The complication arises when we have a time-varying signal, such as an alternating current (AC), e.g, an audio signal or an RF signal.  In the case of power, the most elementary time-varying function involved is the sine function.

When measuring the power dissipated in a load carrying an AC signal, we have different ways of measuring that power.  One is the instantaneous or time-varying power, which is Equation 1 applied all along the sinusoid as a time-varying function.  (We will take R = 1 here, as a way of simplifying the discussion; in practice, we would use an appropriate value, e.g., 50Ω in the case of an RF load.)

In Figure 1, the dotted line (green) trace is our 1-volt (peak) sinusoid. (The horizontal axis is in degrees.) The square of this function (the power as a function of time) is the dark blue trace, which is essentially a “raised cosine” function.  Since the square is always a positive number, we see that the power as a function of time rises and falls as a sinusoid, at twice the frequency of the original voltage.  This function itself has relatively little use in most applications.

Another quantity is the peak power, which is simply Equation 1 above, where V is taken to be the peak value of the sinusoid, in this case, 1.  This is also known as peak instantaneous power (not to be confused with peak envelope power, or PEP).  The peak instantaneous power is useful to understand certain limitations of electronic devices, and is expressed as follows:

$$\large P_{pk}=\frac{V^{2}_{pk}}{R}$$

A more useful quantity is the average power, which will provide the equivalent heating factor in a resistive device.  This is calculated by taking the mean of the square of the voltage signal, divided by the resistance. Since the sinusoidal power function is symmetric about its vertical midpoint, simple inspection (see Figure 1 again) tells us that the mean value is equal to one-half of the peak power [Eq.2]:

$$\large P_{avg}=\frac{P_{pk}}{2}=\frac{V^{2}_{pk}/R}{2}$$

which in this case is equal to 0.5.  We can see this in Figure 1, where the average of the blue trace is the dashed red trace.  Thus, our example of a one-volt-peak sinusoid across a one-ohm resistor will result in an average power of 0.5 watts.

Now the concept of “RMS” comes in, which stands for “root-mean-square,” i.e., the square-root of the mean of the square of a function.  (The “mean” is simply the average.) The purpose of RMS is to present a particular statistical property of that function.  In our case, we want to associate a “constant” value with a time-varying function, one that provides a way of describing the “DC-equivalent heating factor” of a sinusoidal signal.

Taking the square-root of  V2pk/2 therefore provides us with the root-mean-square voltage (not power) across the resistor; in this example, that means that the 1-volt (peak) sinusoid has an RMS voltage of

$$\large V_{rms}=\sqrt{\frac{V^{2}_{pk}}{2}}=\frac{V_{pk}}{\sqrt{2}}\approx 0.7071$$

Thus, if we applied a DC voltage of 0.7071 volts across a 1Ω resistor, it would consume the same power (i.e., dissipate the same heat) as an AC voltage of 1 volt peak.  (Note that the RMS voltage does not depend on the value of the resistance, it is simply related to the peak voltage of the sinusoidal signal.) Plugging this back into Eq. 2 then gives us:

$$\large P_{avg}=\frac{V^{2}_{rms}}{R}$$

Note the RMS voltage is used to calculate the average power. As a rule, then, we can calculate the RMS voltage of a sinusoid this way:

$$\large V_{rms} \approx 0.7071 \cdot V_{pk}$$

Graphically, we can see this in Figure 2:

The astute observer will note that 0.7071 is the value of sin(45°) to four places. This is not a coincidence, but we leave it to the reader to figure out why.  Note that for more complex signals, the 0.7071 factor no longer holds.  A triangle wave, for example, yields Vrms ≈ 0.5774 · Vpk , where 0.5774 is the value of tan(30°) to four places.

For those familiar with calculus, the root-mean-square of an arbitrary function is defined as:

$$\large F_{rms} = \sqrt{\frac{1}{T_{2}-T_{1}}\int_{T_{1}}^{T_{2}}[f(t)]^{2}\, dt}$$

Replacing f(t) with sin(t) (or an appropriate function for a triangle wave) will produce the numerical results we derived above.