Paolo's carbon resistor noise (Motchenbacher p. 290)
* (exec-spice "ngspice %s" t)
*
* check whether resistor flicker noise behaves as expected

.temp 25

i1 1 0 dc 1e-3
r1 1 2 1k rmodel l=1u w=10u
v1 2 0 dc 0 ac 1

.model rmodel r tc1=0.01 kf=100e-18 af=1.1
+ dlr=0.01u dw=0.01u
+ tnom=25

.control

* output noise in v/sqrt(Hz)
compose wanted_onoise values 2.2637m 1.7981m 1.4283m 1.1345m 901.2011u 715.8494u 568.6194u 451.6705u 358.7746u 284.9848u 226.3715u

* equivalent input noise in v/sqrt(Hz)
*   extern_onoise / H
let wanted_inoise = wanted_onoise

noise v(1) v1 dec 5 1k 100k

setplot noise2
*print all

setplot noise1
*print onoise_spectrum wanted_onoise
*print inoise_spectrum wanted_inoise

let inoise_relerr = vecmax(abs(inoise_spectrum / wanted_inoise - 1))
let onoise_relerr = vecmax(abs(onoise_spectrum / wanted_onoise - 1))

echo "Note: relative inoise_relerr = $&inoise_relerr"
echo "Note: relative onoise_relerr = $&onoise_relerr"

if inoise_relerr > 1e-4 or onoise_relerr > 1e-4
  echo "ERROR: test failed"
  quit 1
else
  echo "INFO: success"
  quit 0
end

.endc
.end